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{{Short description|Technology with features near one nanometer}}
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{{Nanotechnology}} {{Nanotechnology}}
'''Nanotechnology''' (sometimes shortened to "'''nanotech'''") is the manipulation of matter on an ]ic and ] scale. The earliest, widespread description of nanotechnology<ref name=Engines1>{{cite book|last=Drexler|first=K. Eric|title=Engines of Creation: The Coming Era of Nanotechnology|year=1986|publisher=Doubleday|isbn=0-385-19973-2}}</ref><ref name=Nanotsystems>{{cite book|last=Drexler|first=K. Eric|title=Nanosystems: Molecular Machinery, Manufacturing, and Computatin|year=1992|publisher=John Wiley & Sons|location=New York|isbn=0-471-57547-X}}</ref> referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as ]. A more generalized description of nanotechnology was subsequently established by the ], which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 ]. This definition reflects the fact that ] effects are important at this ] scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter that occur below the given size threshold. It is therefore common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to the broad range of research and applications whose common trait is size. Because of the variety of potential applications (including industrial and military), governments have invested billions of dollars in nanotechnology research. Through its National Nanotechnology Initiative, the USA has invested 3.7 billion dollars. The European Union has invested 1.2 billion and Japan 750 million dollars.<ref>, ], 17 April 2012.</ref>


'''Nanotechnology''' is the manipulation of matter with at least one dimension sized from 1 to 100 ] (nm). At this scale, commonly known as the '''nanoscale''', ] and ] effects become important in describing properties of matter. This definition of nanotechnology includes all types of research and technologies that deal with these special properties. It is common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to research and applications whose common trait is scale.<ref name="Engines1">{{cite book| vauthors = Drexler KE |title=Engines of Creation: The Coming Era of Nanotechnology |url= https://archive.org/details/enginesofcreatio00drex |oclc=12752328 |url-access=registration |year=1986 |publisher=Doubleday|isbn=978-0-385-19973-5}}</ref> An earlier understanding of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabricating macroscale products, now referred to as ].<ref name="Nanotsystems">{{cite book| vauthors = Drexler KE |title=Nanosystems: Molecular Machinery, Manufacturing, and Computation|url=https://books.google.com/books?id=F6BRAAAAMAAJ|oclc=26503231|year=1992|publisher=Wiley |isbn=978-0-471-57547-4}}</ref>
Nanotechnology as defined by size is naturally very broad, including fields of science as diverse as ], ], ], ], ], etc.<ref>{{cite journal|last=Saini|first=Rajiv|coauthors=Saini, Santosh, Sharma, Sugandha|title=Nanotechnology: The Future Medicine|journal=Journal of Cutaneous and Aesthetic Surgery|year=2010|volume=3|issue=1|pages=32–33|doi=10.4103/0974-2077.63301|pmc=2890134|pmid=20606992}}</ref> The associated research and applications are equally diverse, ranging from extensions of conventional ] to completely new approaches based upon ], from developing ] with dimensions on the nanoscale to ].


Nanotechnology defined by scale includes fields of science such as ], ], ], ], ],<ref>{{cite journal| vauthors = Hubler A |s2cid=6994736|title=Digital quantum batteries: Energy and information storage in nanovacuum tube arrays|journal=Complexity|pages=48–55|volume=15|issue=5|date=2010|doi=10.1002/cplx.20306|doi-access=free| issn = 1076-2787}}</ref><ref>{{cite journal| vauthors = Shinn E |s2cid=35742708|title=Nuclear energy conversion with stacks of graphene nanocapacitors|journal=Complexity|date=2012|doi=10.1002/cplx.21427|bibcode=2013Cmplx..18c..24S|volume=18|issue=3|pages=24–27}}</ref> ],<ref>{{cite book | vauthors = Elishakoff I, Dujat K, Muscolino G, Bucas S, Natsuki T, Wang CM, Pentaras D, Versaci C, Storch J, Challamel N, Zhang Y | title = Carbon Nanotubes and Nano Sensors: Vibrations, Buckling, and Ballistic Impact | publisher = John Wiley & Sons | date = March 2013 | isbn = 978-1-84821-345-6 }}</ref> ],<ref>{{cite journal| vauthors = Lyon D, Hubler A |s2cid=709782|title=Gap size dependence of the dielectric strength in nano vacuum gaps|journal=]|date=2013|doi=10.1109/TDEI.2013.6571470|volume=20|issue=4|pages=1467–71}}</ref> and ].<ref>{{cite journal | vauthors = Saini R, Saini S, Sharma S | title = Nanotechnology: the future medicine | journal = Journal of Cutaneous and Aesthetic Surgery | volume = 3 | issue = 1 | pages = 32–33 | date = January 2010 | pmid = 20606992 | pmc = 2890134 | doi = 10.4103/0974-2077.63301 | doi-access = free }}</ref> The associated research and applications range from extensions of conventional ] to ],<ref>{{cite journal | vauthors = Belkin A, Hubler A, Bezryadin A | title = Self-assembled wiggling nano-structures and the principle of maximum entropy production | journal = Scientific Reports | volume = 5 | pages = 8323 | date = February 2015 | pmid = 25662746 | pmc = 4321171 | doi = 10.1038/srep08323 | bibcode = 2015NatSR...5.8323B }}</ref> from developing ] with dimensions on the nanoscale to ].
Scientists currently debate the future ]. Nanotechnology may be able to create many new materials and devices with a vast range of ], such as in ], ], ] and energy production. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the ] and environmental impact of nanomaterials,<ref>{{cite journal|author= Cristina Buzea, Ivan Pacheco, and Kevin Robbie|title=Nanomaterials and Nanoparticles: Sources and Toxicity|volume=2|year=2007|journal=Biointerphases|doi=10.1116/1.2815690|pmid=20419892|issue= 4|pages= MR17–71}}</ref> and their potential effects on global economics, as well as speculation about various ]. These concerns have led to a debate among advocacy groups and governments on whether special ] is warranted.

Nanotechnology may be able to create new materials and devices with diverse ], such as in ], ], ]s energy production, and consumer products. However, nanotechnology raises issues, including concerns about the ] and environmental impact of nanomaterials,<ref>{{cite journal | vauthors = Buzea C, Pacheco II, Robbie K | title = Nanomaterials and nanoparticles: sources and toxicity | journal = Biointerphases | volume = 2 | issue = 4 | pages = MR17–MR71 | date = December 2007 | pmid = 20419892 | doi = 10.1116/1.2815690 | arxiv = 0801.3280 | s2cid = 35457219 }}</ref> and their potential effects on global economics, as well as various ]. These concerns have led to a debate among advocacy groups and governments on whether special ] is warranted.


==Origins== ==Origins==
{{Main|History of nanotechnology}} {{Main|History of nanotechnology}}
The concepts that seeded nanotechnology were first discussed in 1959 by renowned physicist ] in his talk '']'', in which he described the possibility of synthesis via direct manipulation of atoms. The term "nano-technology" was first used by ] in 1974, though it was not widely known. The concepts that seeded nanotechnology were first discussed in 1959 by physicist ] in his talk '']'', in which he described the possibility of synthesis via direct manipulation of atoms.


]
Inspired by Feynman's concepts, ] independently used the term "nanotechnology" in his 1986 book '']'', which proposed the idea of a nanoscale "assembler" which would be able to build a copy of itself and of other items of arbitrary complexity with atomic control. Also in 1986, Drexler co-founded ] (with which he is no longer affiliated) to help increase public awareness and understanding of nanotechnology concepts and implications.


The term "nano-technology" was first used by ] in 1974, though it was not widely known. Inspired by Feynman's concepts, ] used the term "nanotechnology" in his 1986 book '']'', which proposed the idea of a nanoscale "assembler" that would be able to build a copy of itself and of other items of arbitrary complexity with atom-level control. Also in 1986, Drexler co-founded ] to increase public awareness and understanding of nanotechnology concepts and implications.
Thus, emergence of nanotechnology as a field in the 1980s occurred through convergence of Drexler's theoretical and public work, which developed and popularized a conceptual framework for nanotechnology, and high-visibility experimental advances that drew additional wide-scale attention to the prospects of atomic control of matter.


For example, the invention of the ] in 1981 provided unprecedented visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope's developers ] and ] at ] received a ] in 1986.<ref name="Binnig">{{Cite journal|first1=G. |last1=Binnig |first2=H. |last2=Rohrer|title=Scanning tunneling microscopy|journal=IBM Journal of Research and Development|volume=30|page=4|year=1986}}</ref><ref>{{cite web|title=Press Release: the 1986 Nobel Prize in Physics|url=http://nobelprize.org/nobel_prizes/physics/laureates/1986/press.html|publisher=Nobelprize.org|accessdate=12 May 2011|date=15 October 1986}}</ref> Binnig, ] and Gerber also invented the analogous ] that year. The emergence of nanotechnology as a field in the 1980s occurred through the convergence of Drexler's theoretical and public work, which developed and popularized a conceptual framework, and high-visibility experimental advances that drew additional attention to the prospects. In the 1980s, two breakthroughs sparked the growth of nanotechnology. First, the invention of the ] in 1981 enabled visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope's developers ] and ] at ] received a ] in 1986.<ref name="Binnig">{{Cite journal| vauthors = Binnig G, Rohrer H |title=Scanning tunneling microscopy|journal=IBM Journal of Research and Development|volume=30|issue=4|year=1986|pages=355–369 |doi=10.1147/rd.441.0279}}</ref><ref>{{cite web|title=Press Release: the 1986 Nobel Prize in Physics|url=http://nobelprize.org/nobel_prizes/physics/laureates/1986/press.html|publisher=Nobelprize.org|access-date=12 May 2011|date=15 October 1986|url-status=live|archive-url=https://web.archive.org/web/20110605005907/http://nobelprize.org/nobel_prizes/physics/laureates/1986/press.html|archive-date=5 June 2011}}</ref> Binnig, ] and Gerber also invented the analogous ] that year.


], is a representative member of the ] known as ]s. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.]] ] C<sub>60</sub>, also known as the ], is a representative member of the ] known as ]s. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.]]


] were discovered in 1985 by ], ], and ], who together won the 1996 ].<ref>{{cite journal |doi=10.1038/318162a0 |title=C60: Buckminsterfullerene |year=1985 |last1=Kroto |first1=H. W. |last2=Heath |first2=J. R. |last3=O'Brien |first3=S. C. |last4=Curl |first4=R. F. |last5=Smalley |first5=R. E. |journal=Nature |volume=318 |issue=6042 |pages=162–163 |bibcode=1985Natur.318..162K}}</ref><ref>{{Cite news|pmid = 16373566|last=Adams|first=W Wade|last2=Baughman|first2=Ray H|publication-date=Dec 23, 2005|year=2005|title=Retrospective: Richard E. Smalley (1943–2005)|volume=310|issue=5756|periodical=]|page=1916|doi = 10.1126/science.1122120|postscript = <!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}</ref> C<sub>60</sub> was not initially described as nanotechnology; the term was used regarding subsequent work with related ] tubes (called ]s and sometimes called Bucky tubes) which suggested potential applications for nanoscale electronics and devices. Second, ] (buckyballs) were discovered in 1985 by ], ], and ], who together won the 1996 ].<ref>{{Cite journal | vauthors = Kroto HW, Heath JR, O'Brien SC, Curl RF, Smalley RE |doi=10.1038/318162a0|title=C<sub>60</sub>: Buckminsterfullerene|journal=Nature|volume=318|issue=6042|pages=162–3 |year=1985 |s2cid=4314237|bibcode=1985Natur.318..162K}}</ref><ref>{{cite journal | vauthors = Adams WW, Baughman RH | title = Retrospective: Richard E. Smalley (1943-2005) | journal = Science | volume = 310 | issue = 5756 | pages = 1916 | date = December 2005 | pmid = 16373566 | doi = 10.1126/science.1122120 | doi-access = free }}</ref> C<sub>60</sub> was not initially described as nanotechnology; the term was used regarding subsequent work with related ]s (sometimes called ] tubes or Bucky tubes) which suggested potential applications for nanoscale electronics and devices. The discovery of ] is largely attributed to ] of ] in 1991,<ref name="carbon">{{Cite journal|title=Who should be given the credit for the discovery of carbon nanotubes?|doi=10.1016/j.carbon.2006.03.019| vauthors = Monthioux M, Kuznetsov V |journal=]|volume=44|year=2006|url=http://www.cemes.fr/fichpdf/GuestEditorial.pdf|pages=1621–3|issue=9|bibcode=2006Carbo..44.1621M|access-date=2019-07-09|archive-date=2009-09-29|archive-url=https://web.archive.org/web/20090929073818/http://www.cemes.fr/fichpdf/GuestEditorial.pdf|url-status=dead}}</ref> for which Iijima won the inaugural 2008 ] in Nanoscience.


In the early 2000s, the field garnered increased scientific, political, and commercial attention that led to both controversy and progress. Controversies emerged regarding the definitions and potential implications of nanotechnologies, exemplified by the ]'s report on nanotechnology.<ref name="royalsociety">{{cite web |publisher=Royal Society and Royal Academy of Engineering |title=Nanoscience and nanotechnologies: opportunities and uncertainties |date=July 2004 |url=http://www.nanotec.org.uk/finalReport.htm |accessdate=13 May 2011}}</ref> Challenges were raised regarding the feasibility of applications envisioned by advocates of molecular nanotechnology, which culminated in a public debate between Drexler and Smalley in 2001 and 2003.<ref name="counterpoint">{{cite journal |url=http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html |title=Nanotechnology: Drexler and Smalley make the case for and against 'molecular assemblers' |journal=Chemical & Engineering News |volume=81 |issue=48 |pages=37–42 |publisher=American Chemical Society |date=1 December 2003 |accessdate=9 May 2010 |doi=10.1021/cen-v081n036.p037}}</ref> In the early 2000s, the field garnered increased scientific, political, and commercial attention that led to both controversy and progress. Controversies emerged regarding the definitions and potential implications of nanotechnologies, exemplified by the ]'s report on nanotechnology.<ref name="royalsociety">{{cite web |date=July 2004 |title=Nanoscience and nanotechnologies: opportunities and uncertainties |url=http://www.nanotec.org.uk/finalReport.htm |url-status=dead |archive-url=https://web.archive.org/web/20110526060835/http://www.nanotec.org.uk/finalReport.htm |archive-date=26 May 2011 |access-date=13 May 2011 |publisher=Royal Society and Royal Academy of Engineering |page=xiii}}</ref> Challenges were raised regarding the feasibility of applications envisioned by advocates of molecular nanotechnology, which culminated in a public debate between Drexler and Smalley in 2001 and 2003.<ref name="counterpoint">{{cite journal|url=http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html|title=Nanotechnology: Drexler and Smalley make the case for and against 'molecular assemblers'|journal=Chemical & Engineering News|volume=81|issue=48|pages=37–42|date=1 December 2003|access-date=9 May 2010|doi=10.1021/cen-v081n036.p037|doi-access=free }}</ref>


Meanwhile, commercialization of products based on advancements in nanoscale technologies began emerging. These products are limited to bulk applications of ] and do not involve atomic control of matter. Some examples include the ] platform for using ] as an antibacterial agent, ]-based transparent sunscreens, and ]s for stain-resistant textiles.<ref name="americanelements">{{cite web|title=Nanotechnology Information Center: Properties, Applications, Research, and Safety Guidelines|url=http://www.americanelements.com/nanotech.htm|publisher=]|accessdate=13 May 2011}}</ref><ref name="emergingnano">{{cite web |year=2008 |url=http://www.nanotechproject.org/inventories/consumer/analysis_draft/ |publisher=The Project on Emerging Nanotechnologies |title=Analysis: This is the first publicly available on-line inventory of nanotechnology-based consumer products |accessdate=13 May 2011}}</ref> Meanwhile, commercial products based on advancements in nanoscale technologies began emerging. These products were limited to bulk applications of ] and did not involve atomic control of matter. Some examples include the ] platform for using ] as an ], ]-based sunscreens, ] strengthening using ] nanoparticles, and carbon nanotubes for stain-resistant textiles.<ref name="americanelements">{{cite web|title=Nanotechnology Information Center: Properties, Applications, Research, and Safety Guidelines|url=http://www.americanelements.com/nanomaterials-nanoparticles-nanotechnology.html|publisher=]|access-date=13 May 2011|url-status=live|archive-url=https://web.archive.org/web/20141226011154/http://www.americanelements.com/nanomaterials-nanoparticles-nanotechnology.html|archive-date=26 December 2014}}</ref><ref name="emergingnano">{{cite web|year=2008|url=http://www.nanotechproject.org/inventories/consumer/analysis_draft/|publisher=The Project on Emerging Nanotechnologies|title=Analysis: This is the first publicly available on-line inventory of nanotechnology-based consumer products|access-date=13 May 2011|url-status=live|archive-url=https://web.archive.org/web/20110505011238/http://www.nanotechproject.org/inventories/consumer/analysis_draft/|archive-date=5 May 2011 }}</ref>


Governments moved to promote and ] into nanotechnology, beginning in the U.S. with the ], which formalized a size-based definition of nanotechnology and established funding for research on the nanoscale. Governments moved to promote and ] into nanotechnology, such as American the ], which formalized a size-based definition of nanotechnology and established research funding, and in Europe via the European ].


By the mid-2000s new and serious scientific attention began to flourish. Projects emerged to produce nanotechnology roadmaps<ref name=PNRoadmap>{{cite web|title=Productive Nanosystems Technology Roadmap|url=http://www.productivenanosystems.com/docs/Nanotech_Roadmap_2007_main.pdf}}</ref><ref name=NASAroadmap>{{cite web|title=NASA Draft Nanotechnology Roadmap|url=http://www.nasa.gov/pdf/501325main_TA10-Nanotech-DRAFT-Nov2010-A.pdf}}</ref> which center on atomically precise manipulation of matter and discuss existing and projected capabilities, goals, and applications. By the mid-2000s scientific attention began to flourish. Nanotechnology roadmaps centered on atomically precise manipulation of matter and discussed existing and projected capabilities, goals, and applications.<ref name="PNRoadmap">{{cite web |title=Productive Nanosystems Technology Roadmap |url=http://www.productivenanosystems.com/docs/Nanotech_Roadmap_2007_main.pdf |url-status=live |archive-url= https://web.archive.org/web/20130908014630/http://www.productivenanosystems.com/docs/Nanotech_Roadmap_2007_main.pdf |archive-date=2013-09-08}}</ref><ref name="NASAroadmap">{{cite web |title=NASA Draft Nanotechnology Roadmap |url=http://www.nasa.gov/pdf/501325main_TA10-Nanotech-DRAFT-Nov2010-A.pdf |url-status=live |archive-url=https://web.archive.org/web/20130122114146/http://www.nasa.gov/pdf/501325main_TA10-Nanotech-DRAFT-Nov2010-A.pdf |archive-date=2013-01-22}}</ref>


==Fundamental concepts== ==Fundamental concepts==
Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products. Nanotechnology is the science and engineering of functional systems at the molecular scale. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up making complete, high-performance products.


One ] (nm) is one billionth, or 10<sup>−9</sup>, of a meter. By comparison, typical carbon-carbon ]s, or the spacing between these ]s in a ], are in the range {{nowrap|0.12–0.15 nm}}, and a ] double-helix has a diameter around 2&nbsp;nm. On the other hand, the smallest ] life-forms, the bacteria of the genus ], are around 200&nbsp;nm in length. By convention, nanotechnology is taken as the scale range {{nowrap|1 to 100 nm}} following the definition used by the National Nanotechnology Initiative in the US. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of a nm diameter) since nanotechnology must build its devices from atoms and molecules. The upper limit is more or less arbitrary but is around the size that phenomena not observed in larger structures start to become apparent and can be made use of in the nano device.<ref>{{cite book |first=Fritz |last=Allhoff |first2=Patrick |last2=Lin |first3=Daniel |last3=Moore |title=What is nanotechnology and why does it matter?: from science to ethics |pages=3–5 |location= |publisher=John Wiley and Sons |year=2010 |isbn=1-4051-7545-1 }}</ref> These new phenomena make nanotechnology distinct from devices which are merely miniaturised versions of an equivalent ] device; such devices are on a larger scale and come under the description of ].<ref>{{cite book |first=S. K. |last=Prasad |title=Modern Concepts in Nanotechnology |pages=31–32 |publisher=Discovery Publishing House |year=2008 |isbn=81-8356-296-5 }}</ref> One ] (nm) is one billionth, or 10<sup>−9</sup>, of a meter. By comparison, typical carbon–carbon ]s, or the spacing between these ]s in a ], are in the range {{nowrap|0.12–0.15 nm}}, and ]'s diameter is around 2&nbsp;nm. On the other hand, the smallest ] life forms, the bacteria of the genus '']'', are around 200&nbsp;nm in length. By convention, nanotechnology is taken as the scale range {{nowrap|1 to 100 nm}}, following the definition used by the American ]. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which have an approximately ,25&nbsp;nm ]). The upper limit is more or less arbitrary, but is around the size below which phenomena not observed in larger structures start to become apparent and can be made use of.<ref>{{cite book| vauthors = Allhoff F, Lin P, Moore D |title=What is nanotechnology and why does it matter?: from science to ethics|pages=3–5|publisher=Wiley |year=2010|isbn=978-1-4051-7545-6 |oclc=830161740}}</ref> These phenomena make nanotechnology distinct from devices that are merely miniaturized versions of an equivalent ] device; such devices are on a larger scale and come under the description of ].<ref>{{cite book| vauthors = Prasad SK |title=Modern Concepts in Nanotechnology|pages=31–32|publisher=Discovery Publishing House|year=2008|isbn=978-81-8356-296-6 |oclc=277278905}}</ref>


To put that scale in another context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth.<ref name="NationalG">{{cite journal|last =Kahn| first =Jennifer |title=Nanotechnology|journal=National Geographic |volume=2006 |issue=June |pages=98–119 |year=2006}}</ref> Or another way of putting it: a nanometer is the amount an average man's beard grows in the time it takes him to raise the razor to his face.<ref name="NationalG"/> To put that scale in another context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth.<ref name="NationalG">{{cite journal| vauthors = Kahn J | title=Nanotechnology|journal=National Geographic|volume=2006|issue=June|pages=98–119|year=2006}}</ref>


Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which ] chemically by principles of ]. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.<ref>{{cite journal|journal=Nature Nanotechnology|author=Rodgers, P. |year=2006|title=Nanoelectronics: Single file|doi=10.1038/nnano.2006.5}}</ref> Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which ] chemically by principles of ].<ref name="ReferenceA">{{cite journal | vauthors = Kralj S, Makovec D | title = Magnetic Assembly of Superparamagnetic Iron Oxide Nanoparticle Clusters into Nanochains and Nanobundles | journal = ACS Nano | volume = 9 | issue = 10 | pages = 9700–7 | date = October 2015 | pmid = 26394039 | doi = 10.1021/acsnano.5b02328 }}</ref> In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.<ref>{{cite journal|journal=Nature Nanotechnology| vauthors = Rodgers P |year=2006|title=Nanoelectronics: Single file|doi=10.1038/nnano.2006.5|doi-access=free}}</ref>


Areas of physics such as ], ], ] and ] have evolved during the last few decades to provide a basic scientific foundation of nanotechnology. Areas of physics such as ], ], ] and ] have evolved to provide nanotechnology's scientific foundation.


===Larger to smaller: a materials perspective=== ===Larger to smaller: a materials perspective===
] on a clean ](]) surface, as visualized using ]. The positions of the individual atoms composing the surface are visible.]] ] on a clean ](]) surface, as visualized using ]. The positions of the individual atoms composing the surface are visible.]]


{{main|Nanomaterials}} {{main|Nanomaterials}}


Several phenomena become pronounced as the size of the system decreases. These include ] effects, as well as ] effects, for example the ] size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects can become significant when the nanometer size range is reached, typically at distances of 100 nanometers or less, the so-called ]. Additionally, a number of physical (mechanical, electrical, optical, etc.) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to nanoionics. ''Mechanical'' properties of nanosystems are of interest in the nanomechanics research. The catalytic activity of nanomaterials also opens potential risks in their interaction with ]s. Several phenomena become pronounced as system size. These include ] effects, as well as ] effects, for example, the "] size effect" in which the electronic properties of solids alter along with reductions in particle size. Such effects do not apply at macro or micro dimensions. However, quantum effects can become significant when nanometer scales. Additionally, physical (mechanical, electrical, optical, etc.) properties change versus macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal, and catalytic properties of materials. Diffusion and reactions can be different as well. Systems with fast ion transport are referred to as nanoionics. The mechanical properties of nanosystems are of interest in research.

Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances can become transparent (copper); stable materials can turn combustible (aluminum); insoluble materials may become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical ] at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.<ref>{{cite journal | author = Lubick N | year = 2008 | title = Silver socks have cloudy lining | url = | journal = Environ Sci Technol | volume = 42 | issue = 11| page = 3910 | pmid=18589943 | doi = 10.1021/es0871199 | last2 = Betts | first2 = Kellyn|bibcode = 2008EnST...42.3910L }}</ref>


===Simple to complex: a molecular perspective=== ===Simple to complex: a molecular perspective===
{{Main|Molecular self-assembly}} {{Main|Molecular self-assembly}}


Modern ] has reached the point where it is possible to prepare small molecules to almost any structure. These methods are used today to manufacture a wide variety of useful chemicals such as ] or commercial ]s. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble these single molecules into ] consisting of many molecules arranged in a well defined manner. Modern ] can prepare small molecules of almost any structure. These methods are used to manufacture a wide variety of useful chemicals such as ] or commercial ]s. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble single molecules into ] consisting of many molecules arranged in a well-defined manner.


These approaches utilize the concepts of molecular self-assembly and/or ] to automatically arrange themselves into some useful conformation through a ] approach. The concept of molecular recognition is especially important: molecules can be designed so that a specific configuration or arrangement is favored due to ] ]s. The Watson–Crick ] rules are a direct result of this, as is the specificity of an ] being targeted to a single ], or the specific ] itself. Thus, two or more components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole. These approaches utilize the concepts of molecular self-assembly and/or ] to automatically arrange themselves into a useful conformation through a ] approach. The concept of ] is important: molecules can be designed so that a specific configuration or arrangement is favored due to ] ]s. The Watson–Crick ] rules are a direct result of this, as is the specificity of an ] targeting a single ], or the specific ]. Thus, components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.


Such bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, there are many examples of self-assembly based on molecular recognition in ], most notably Watson–Crick basepairing and enzyme-substrate interactions. The challenge for nanotechnology is whether these principles can be used to engineer new constructs in addition to natural ones. Such bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, many examples of self-assembly based on molecular recognition in exist in ], most notably Watson–Crick basepairing and enzyme-substrate interactions.


===Molecular nanotechnology: a long-term view=== ===Molecular nanotechnology: a long-term view===
{{Main|Molecular nanotechnology}} {{Main|Molecular nanotechnology}}


Molecular nanotechnology, sometimes called molecular manufacturing, describes engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology is especially associated with the ], a machine that can produce a desired structure or device atom-by-atom using the principles of ]. Manufacturing in the context of ] is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles. Molecular nanotechnology, sometimes called molecular manufacturing, concerns engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology is especially associated with ]s, machines that can produce a desired structure or device atom-by-atom using the principles of ]. Manufacturing in the context of ] is not related to conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.


When the term "nanotechnology" was independently coined and popularized by ] (who at the time was unaware of an ] by Norio Taniguchi) it referred to a future manufacturing technology based on ] systems. The premise was that molecular scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, ]ally optimised biological machines can be produced. When Drexler independently coined and popularized the term "nanotechnology", he envisioned manufacturing technology based on ] systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated molecular machines were possible: biology was full of examples of sophisticated, ]ally optimized ].


It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using ] principles. However, Drexler and other researchers<ref></ref> have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification.<ref>{{cite web|url=http://www.imm.org/PNAS.html|title=Some papers by K. Eric Drexler}}</ref> The physics and engineering performance of exemplar designs were analyzed in Drexler's book ''Nanosystems''. Drexler and other researchers<ref>{{cite web| vauthors = Phoenix C |date=March 2005|url=http://www.crnano.org/developing.htm|title=Nanotechnology: Developing Molecular Manufacturing|archive-url=https://web.archive.org/web/20200601095107/http://www.crnano.org/developing.htm|archive-date=2020-06-01}}. crnano.org</ref> have proposed that advanced nanotechnology ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification.<ref>{{cite web|url=http://www.imm.org/PNAS.html|title=Some papers by K. Eric Drexler|work=imm.org|url-status=live|archive-url=https://web.archive.org/web/20060411075149/http://www.imm.org/PNAS.html|archive-date=2006-04-11}}</ref> The physics and engineering performance of exemplar designs were analyzed in Drexler's book ''Nanosystems: Molecular Machinery, Manufacturing, and Computation''.<ref name=Nanotsystems />


In general it is very difficult to assemble devices on the atomic scale, as one has to position atoms on other atoms of comparable size and stickiness. Another view, put forth by Carlo Montemagno,<ref></ref> is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Richard Smalley argued that mechanosynthesis are impossible due to the difficulties in mechanically manipulating individual molecules. In general, assembling devices on the atomic scale requires positioning atoms on other atoms of comparable size and stickiness. ]'s view is that future nanosystems will be hybrids of silicon technology and biological molecular machines.<ref>{{cite web |title=Carlo Montemagno, Ph.D. |url=http://www.cnsi.ucla.edu/institution/personnel?personnel%5fid=105488 |archive-url=https://web.archive.org/web/20141008065938/http://faculty.cnsi.ucla.edu/institution/personnel?personnel%5fid=105488 |archive-date=2014-10-08 |website=California NanoSystems Institute (CNSI), University of California, Los Angeles (UCLA)}}</ref> ] argued that mechanosynthesis was impossible due to difficulties in mechanically manipulating individual molecules.{{Citation needed|date=May 2024}}


This led to an exchange of letters in the ] publication ] in 2003.<ref></ref> Though biology clearly demonstrates that molecular machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dr. ] and his colleagues at Lawrence Berkeley Laboratories and UC Berkeley. They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube ], a molecular actuator,<ref>{{cite journal|url=http://www.physics.berkeley.edu/research/zettl/pdf/312.NanoLett5regan.pdf|doi=10.1021/nl0510659|pmid=16159214|year=2005|last1=Regan|first1=BC|last2=Aloni|first2=S|last3=Jensen|first3=K|last4=Ritchie|first4=RO|last5=Zettl|first5=A|title=Nanocrystal-powered nanomotor|volume=5|issue=9|pages=1730–3|journal=Nano letters|bibcode = 2005NanoL...5.1730R }}</ref> and a nanoelectromechanical relaxation oscillator.<ref>{{cite journal|url=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/May/Tiniest-Motor.pdf|doi=10.1063/1.1887827|title=Surface-tension-driven nanoelectromechanical relaxation oscillator|year=2005|last1=Regan|first1=B. C.|last2=Aloni|last3=Jensen|last4=Zettl|journal=Applied Physics Letters|volume=86|page=123119|first2=S.|first3=K.|first4=A.|bibcode = 2005ApPhL..86l3119R|issue=12 }}</ref> See ] for more examples. This led to an exchange of letters in the ] publication ] in 2003.<ref>{{cite journal | vauthors = Baum R |url=http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html|title=Cover Story – Nanotechnology|date=December 1, 2003|volume=81|issue=48|journal=Chemical and Engineering News|pages=37–42}}</ref> Though biology clearly demonstrates that molecular machines are possible, non-biological molecular machines remained in their infancy. ] and colleagues at Lawrence Berkeley Laboratories and UC Berkeley<ref>{{cite web|url=http://research.physics.berkeley.edu/zettl/|archive-url=https://web.archive.org/web/20151008062820/http://research.physics.berkeley.edu/zettl/|archive-date=2015-10-08|title=Zettl Research Group |publisher=Department of Physics, University of California, Berkeley}}</ref> constructed at least three molecular devices whose motion is controlled via changing voltage: a nanotube ], a molecular actuator,<ref>{{cite journal | vauthors = Regan BC, Aloni S, Jensen K, Ritchie RO, Zettl A | title = Nanocrystal-powered nanomotor | journal = Nano Letters | volume = 5 | issue = 9 | pages = 1730–3 | date = September 2005 | pmid = 16159214 | doi = 10.1021/nl0510659 | url = http://www.physics.berkeley.edu/research/zettl/pdf/312.NanoLett5regan.pdf | url-status = dead | osti = 1017464 | bibcode = 2005NanoL...5.1730R | archive-url = https://web.archive.org/web/20060510143208/http://www.physics.berkeley.edu/research/zettl/pdf/312.NanoLett5regan.pdf | archive-date = 2006-05-10 }}</ref> and a nanoelectromechanical relaxation oscillator.<ref>{{cite journal|url=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/May/Tiniest-Motor.pdf|doi=10.1063/1.1887827|title=Surface-tension-driven nanoelectromechanical relaxation oscillator|year=2005| vauthors = Regan BC, Aloni S, Jensen K, Zettl A |journal=Applied Physics Letters |volume=86 |page=123119 |bibcode=2005ApPhL..86l3119R|issue=12|url-status=live|archive-url=https://web.archive.org/web/20060526193318/http://www.lbl.gov/Science-Articles/Archive/sabl/2005/May/Tiniest-Motor.pdf|archive-date=2006-05-26}}</ref>


An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at ] in 1999. They used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal, and chemically bound the CO to the Fe by applying a voltage. Ho and Lee at ] in 1999 used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal and chemically bound the CO to the Fe by applying a voltage.{{Citation needed|date=May 2024}}


==Research==
==Current research==
], useful as a molecular switch.]] ], useful as a ]]]
] |volume=310 |issue=5754 |pages=1661–1665 |issn=0036-8075 |pmid=16339440|doi=10.1126/science.1120367|bibcode = 2005Sci...310.1661G }}</ref> is an artificially ] nanostructure of the type made in the field of ]. Each edge of the tetrahedron is a 20 base pair DNA ], and each vertex is a three-arm junction.]] ]<ref name="Goodman05">{{cite journal | vauthors = Goodman RP, Schaap IA, Tardin CF, Erben CM, Berry RM, Schmidt CF, Turberfield AJ | title = Rapid chiral assembly of rigid DNA building blocks for molecular nanofabrication | journal = Science | volume = 310 | issue = 5754 | pages = 1661–5 | date = December 2005 | pmid = 16339440 | doi = 10.1126/science.1120367 | s2cid = 13678773 | bibcode = 2005Sci...310.1661G }}</ref> is an artificially ] nanostructure of the type made in the field of ]. Each edge of the tetrahedron is a 20 base pair DNA ], and each vertex is a three-arm junction.]]
]
]s to ]s above them, causing the nanocrystals to emit visible light.<ref></ref>]]
]s to nanocrystals above them, causing the nanocrystals to emit visible light.<ref>{{cite web |url= http://www.photonicsonline.com/doc.mvc/Wireless-Nanocrystals-Efficiently-Radiate-Vis-0002 |title=Wireless Nanocrystals Efficiently Radiate Visible Light | date = 12 July 2004 | work = Photonics Online |access-date=5 August 2015 |url-status=live|archive-url=https://web.archive.org/web/20121114102922/http://www.photonicsonline.com/doc.mvc/Wireless-Nanocrystals-Efficiently-Radiate-Vis-0002|archive-date=14 November 2012}}</ref>]]


===Nanomaterials=== ===Nanomaterials===
The nanomaterials field includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions.<ref>{{cite journal |title=Nanostructured Ceramics in Medical Devices: Applications and Prospects |journal=JOM |volume=56 |issue=10|pages=38–43 |year=2004|doi = 10.1007/s11837-004-0289-x |pmid=11196953 |first1=R. J.|last1=Narayan|first2=P. N.|last2=Kumta|first3=Ch.|last3=Sfeir|first4=D-H |last4=Lee|first5=D.|last5=Choi|first6=D.|last6=Olton Many areas of science develop or study materials having unique properties arising from their nanoscale dimensions.<ref>{{cite journal | title = Nanostructured Ceramics in Medical Devices: Applications and Prospects | journal = JOM | volume = 56 | issue = 10 | pages = 38–43 | year = 2004 | doi = 10.1007/s11837-004-0289-x | vauthors = Narayan RJ, Kumta PN, Sfeir C, Lee DH, Choi D, Olton D | s2cid = 137324362 | bibcode = 2004JOM....56j..38N }}</ref>
*] produced many materials that may be useful in nanotechnology, such as carbon nanotubes and other ], and various nanoparticles and ]s. Nanomaterials with fast ion transport are related to nanoionics and nanoelectronics.
| bibcode = 2004JOM....56j..38N }}</ref>
*Nanoscale materials can be used for bulk applications; most commercial applications of nanotechnology are of this flavor.
*] has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various nanoparticles and ]s. Nanomaterials with fast ion transport are related also to nanoionics and nanoelectronics.
*Progress has been made in using these materials for ], including ], ], ] and ]s.<ref>{{cite journal | vauthors = Cho H, Pinkhassik E, David V, Stuart JM, Hasty KA | title = Detection of early cartilage damage using targeted nanosomes in a post-traumatic osteoarthritis mouse model | journal = Nanomedicine | volume = 11 | issue = 4 | pages = 939–946 | date = May 2015 | pmid = 25680539 | doi = 10.1016/j.nano.2015.01.011 }}</ref><ref>{{cite journal | vauthors = Kerativitayanan P, Carrow JK, Gaharwar AK | title = Nanomaterials for Engineering Stem Cell Responses | journal = Advanced Healthcare Materials | volume = 4 | issue = 11 | pages = 1600–27 | date = August 2015 | pmid = 26010739 | doi = 10.1002/adhm.201500272 | s2cid = 21582516 }}</ref><ref>{{cite book |title=Nanomaterials in tissue engineering : fabrication and applications |date=2013 |publisher=Woodhead Publishing |isbn=978-0-85709-596-1 | veditors = Gaharwar A, Sant S, Hancock M, Hacking S |location=Oxford |doi=10.1533/9780857097231 |last1=Gaharwar |first1=A. K. |last2=Sant |first2=S. |last3=Hancock |first3=M. J. |last4=Hacking |first4=S. A. }}</ref><ref>{{cite journal | vauthors = Gaharwar AK, Peppas NA, Khademhosseini A | title = Nanocomposite hydrogels for biomedical applications | journal = Biotechnology and Bioengineering | volume = 111 | issue = 3 | pages = 441–453 | date = March 2014 | pmid = 24264728 | pmc = 3924876 | doi = 10.1002/bit.25160 }}</ref><ref>{{cite journal | vauthors = Eslamian L, Borzabadi-Farahani A, Karimi S, Saadat S, Badiee MR | title = Evaluation of the Shear Bond Strength and Antibacterial Activity of Orthodontic Adhesive Containing Silver Nanoparticle, an In-Vitro Study | journal = Nanomaterials | volume = 10 | issue = 8 | pages = 1466 | date = July 2020 | pmid = 32727028 | pmc = 7466539 | doi = 10.3390/nano10081466 | doi-access = free }}</ref>
*Nanoscale materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor.
*Nanoscale materials such as ]s are used in ]s.
*Progress has been made in using these materials for medical applications; see ].
*Applications incorporating semiconductor ]s in products such as display technology, lighting, solar cells and biological imaging; see ]s.
*Nanoscale materials such as ] are sometimes used in ] which combats the cost of traditional ] solar cells.
*Development of applications incorporating semiconductor ] to be used in the next generation of products, such as display technology, lighting, solar cells and biological imaging; see ].


===Bottom-up approaches=== ===Bottom-up approaches===
These seek to arrange smaller components into more complex assemblies. The bottom-up approach seeks to arrange smaller components into more complex assemblies.
*DNA nanotechnology utilizes the specificity of Watson–Crick basepairing to construct well-defined structures out of DNA and other ]s. *DNA nanotechnology utilizes Watson–Crick basepairing to construct well-defined structures out of DNA and other ]s.
*Approaches from the field of "classical" chemical synthesis (] and ]) also aim at designing molecules with well-defined shape (e.g. ]s<ref name="Levins">{{cite journal|doi=10.1002/chin.200605222|title=The Synthesis of Curved and Linear Structures from a Minimal Set of Monomers|year=2006|last1=Levins|first1=Christopher G.|last2=Schafmeister|first2=Christian E.|journal=ChemInform|volume=37|issue=5}}</ref>). *Approaches from the field of "classical" chemical synthesis (inorganic and ]) aim at designing molecules with well-defined shape (e.g. ]s<ref name="Levins">{{cite journal|doi=10.1002/chin.200605222|title=The Synthesis of Curved and Linear Structures from a Minimal Set of Monomers|year=2006| vauthors = Levins CG, Schafmeister CE |journal=ChemInform |volume=37 |issue=5 |url= https://figshare.com/articles/The_Synthesis_of_Curved_and_Linear_Structures_from_a_Minimal_Set_of_Monomers/3260635}}</ref>).
*More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation. *More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation.
*] tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called ]. This technique fits into the larger subfield of ]. *] tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called ]. This technique fits into the larger subfield of ].
*] allows for bottom-up assemblies of materials, most notably semiconductor materials commonly used in chip and computing applications, stacks, gating, and ].


===Top-down approaches=== ===Top-down approaches===
These seek to create smaller devices by using larger ones to direct their assembly. These seek to create smaller devices by using larger ones to direct their assembly.
*Many technologies that descended from conventional ] for fabricating ]s are now capable of creating features smaller than 100&nbsp;nm, falling under the definition of nanotechnology. ]-based hard drives already on the market fit this description,<ref>{{cite web|url = http://www.nano.gov/html/facts/appsprod.html|title = Applications/Products|accessdate=2007-10-19 |publisher = National Nanotechnology Initiative}}{{dead link|date=June 2012}}</ref> as do ] (ALD) techniques. ] and ] received the Nobel Prize in Physics in 2007 for their discovery of Giant magnetoresistance and contributions to the field of spintronics.<ref>{{cite web|url = http://nobelprize.org/nobel_prizes/physics/laureates/2007/index.html|title = The Nobel Prize in Physics 2007|accessdate = 2007-10-19|publisher = Nobelprize.org}}</ref> *Many technologies that descended from conventional ] for fabricating ]s are capable of creating features smaller than 100&nbsp;nm. ]-based hard drives already on the market fit this description,<ref>{{cite web|url=http://www.nano.gov/html/facts/appsprod.html|archive-url=https://web.archive.org/web/20101120234415/http://www.nano.gov/html/facts/appsprod.html|archive-date=2010-11-20|title=Applications/Products|access-date=2007-10-19|publisher=National Nanotechnology Initiative}}</ref> as do ] (ALD) techniques. ] and ] received the Nobel Prize in Physics in 2007 for their discovery of giant magnetoresistance and contributions to the field of ].<ref>{{cite web|url=http://nobelprize.org/nobel_prizes/physics/laureates/2007/index.html|title=The Nobel Prize in Physics 2007|access-date=2007-10-19|publisher=Nobelprize.org|url-status=live|archive-url=https://web.archive.org/web/20110805062614/http://nobelprize.org/nobel_prizes/physics/laureates/2007/index.html|archive-date=2011-08-05}}</ref>
*Solid-state techniques can also be used to create devices known as ] or NEMS, which are related to ] or MEMS. *Solid-state techniques can be used to create ] or NEMS, which are related to ] or MEMS.
*]s can directly remove material, or even deposit material when suitable pre-cursor gasses are applied at the same time. For example, this technique is used routinely to create sub-100&nbsp;nm sections of material for analysis in ]. *]s can directly remove material, or even deposit material when suitable precursor gasses are applied at the same time. For example, this technique is used routinely to create sub-100&nbsp;nm sections of material for analysis in ].
*Atomic force microscope tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by an etching process to remove material in a top-down method. *Atomic force microscope tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by an etching process to remove material in a top-down method.


===Functional approaches=== ===Functional approaches===
These seek to develop components of a desired functionality without regard to how they might be assembled. Functional approaches seek to develop useful components without regard to how they might be assembled.
*Magnetic assembly for the synthesis of ] ] materials such as magnetic nano chains.<ref name="ReferenceA"/>
*] seeks to develop molecules with useful electronic properties. These could then be used as single-molecule components in a nanoelectronic device.<ref>{{cite journal |author=Das S, Gates AJ, Abdu HA, Rose GS, Picconatto CA, Ellenbogen JC. |title=Designs for Ultra-Tiny, Special-Purpose Nanoelectronic Circuits |journal=IEEE Transactions on Circuits and Systems I |volume=54 |issue=11 |pages=2528–2540 |year=2007 |doi=10.1109/TCSI.2007.907864}}</ref> For an example see rotaxane.
*] seeks to develop molecules with useful electronic properties. These could be used as single-molecule components in a nanoelectronic device,<ref>{{cite journal|vauthors=Das S, Gates AJ, Abdu HA, Rose GS, Picconatto CA, Ellenbogen JC|s2cid=13575385|title=Designs for Ultra-Tiny, Special-Purpose Nanoelectronic Circuits|journal=IEEE Transactions on Circuits and Systems I|volume=54|issue=11|pages=2528–40|year=2007|doi=10.1109/TCSI.2007.907864}}</ref> such as ].
*Synthetic chemical methods can also be used to create ], such as in a so-called ].
*Synthetic chemical methods can be used to create ]s, such as in a so-called ].


===Biomimetic approaches=== ===Biomimetic approaches===
* ] or ] seeks to apply biological methods and systems found in nature to the study and design of engineering systems and modern technology. ] is one example of the systems studied.

* ] is the use of ]s for applications in nanotechnology, including the use of viruses and lipid assemblies.<ref>{{cite journal | vauthors = Mashaghi S, Jadidi T, Koenderink G, Mashaghi A | title = Lipid nanotechnology | journal = International Journal of Molecular Sciences | volume = 14 | issue = 2 | pages = 4242–82 | date = February 2013 | pmid = 23429269 | pmc = 3588097 | doi = 10.3390/ijms14024242 | doi-access = free | author3-link = Gijsje Koenderink }}</ref><ref>{{cite web | vauthors = Hogan CM | date = May 2010 | veditors = Draggan S | url = http://www.eoearth.org/article/Virus?topic=49496 | title = Virus | archive-url = https://web.archive.org/web/20130513135007/http://www.eoearth.org/article/Virus?topic=49496| archive-date=2013-05-13|website=Encyclopedia of Earth, National Council for Science and the Environment }}</ref> ], a nanopolymer often used for bulk-scale applications, has gained interest owing to its useful properties such as abundance, high aspect ratio, good ], ], and ].<ref>{{cite journal | vauthors = Trache D, Tarchoun AF, Derradji M, Hamidon TS, Masruchin N, Brosse N, Hussin MH | title = Nanocellulose: From Fundamentals to Advanced Applications | journal = Frontiers in Chemistry | volume = 8 | pages = 392 | date = 2020 | pmid = 32435633 | pmc = 7218176 | doi = 10.3389/fchem.2020.00392 | bibcode = 2020FrCh....8..392T | doi-access = free }}</ref>
* ] or ] seeks to apply biological methods and systems found in nature, to the study and design of engineering systems and modern technology. ] is one example of the systems studied.

* ] is the use of ]s for applications in nanotechnology, including use of viruses and lipid assemblies.<ref>Mashaghi, S.; Jadidi, T.; Koenderink, G.; Mashaghi, A. Lipid Nanotechnology. Int. J. Mol. Sci. 2013, 14, 4242-4282.</ref><ref>C.Michael Hogan. 2010. . eds. S.Draggan and C.Cleveland</ref> ] is a potential bulk-scale application.


===Speculative=== ===Speculative===
These subfields seek to ] what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. These often take a big-picture view of nanotechnology, with more emphasis on its societal implications than the details of how such inventions could actually be created. These subfields seek to ] what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry could progress. These often take a big-picture view, with more emphasis on societal implications than engineering details.
*Molecular nanotechnology is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields, and many of its proposed techniques are beyond current capabilities. *Molecular nanotechnology is a proposed approach that involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields, and many of its proposed techniques are beyond current capabilities.
*] centers on self-sufficient machines of some functionality operating at the nanoscale. There are hopes for applying nanorobots in medicine,<ref>{{cite journal |author=Ghalanbor Z, Marashi SA, Ranjbar B |title=Nanotechnology helps medicine: nanoscale swimmers and their future applications |journal=Med Hypotheses |volume=65 |issue=1 |pages=198–199 |year=2005 |pmid=15893147|doi = 10.1016/j.mehy.2005.01.023}}</ref><ref>{{cite journal |author=Kubik T, Bogunia-Kubik K, Sugisaka M. |title=Nanotechnology on duty in medical applications |journal=Curr Pharm Biotechnol. |volume=6 |issue=1 |pages=17–33 |year=2005 |pmid=15727553}}</ref><ref>{{cite journal |title=Toward the Emergence of Nanoneurosurgery: Part III-Nanomedicine: Targeted Nanotherapy, Nanosurgery, and Progress Toward the Realization of Nanoneurosurgery |journal=Neurosurgery |volume=58 |issue=6 |pages=1009–1026 |year=2006|doi = 10.1227/01.NEU.0000217016.79256.16 |pmid=16723880 |last1=Leary |first1=SP |last2=Liu |first2=CY |last3=Apuzzo |first3=ML}}</ref> but it may not be easy to do such a thing because of several drawbacks of such devices.<ref>{{cite journal |author=Shetty RC|title=Potential pitfalls of nanotechnology in its applications to medicine: immune incompatibility of nanodevices |journal=Med Hypotheses |volume=65 |issue=5 |pages=998–9 |year=2005 |pmid=16023299|doi = 10.1016/j.mehy.2005.05.022}}</ref> Nevertheless, progress on innovative materials and methodologies has been demonstrated with some patents granted about new nanomanufacturing devices for future commercial applications, which also progressively helps in the development towards nanorobots with the use of embedded nanobioelectronics concepts.<ref>{{cite journal |author=Cavalcanti A, Shirinzadeh B, Freitas RA Jr., Kretly LC. |title= Medical Nanorobot Architecture Based on Nanobioelectronics |journal=. |volume=1 |issue=1 |pages=1–10 |year=2007 |doi= 10.2174/187221007779814745}}</ref><ref>{{cite journal |author=Boukallel M, Gauthier M, Dauge M, Piat E, Abadie J. |title= Smart microrobots for mechanical cell characterization and cell convoying |journal=IEEE Trans. Biomed. Eng. |volume=54 |issue=8 |pages=1536–40 |year=2007|pmid=17694877|doi = 10.1109/TBME.2007.891171}}</ref> *] considers self-sufficient machines operating at the nanoscale. There are hopes for applying nanorobots in medicine.<ref>{{cite journal | vauthors = Kubik T, Bogunia-Kubik K, Sugisaka M | title = Nanotechnology on duty in medical applications | journal = Current Pharmaceutical Biotechnology | volume = 6 | issue = 1 | pages = 17–33 | date = February 2005 | pmid = 15727553 | doi = 10.2174/1389201053167248 }}</ref><ref>{{cite journal | vauthors = Leary SP, Liu CY, Apuzzo ML | title = Toward the emergence of nanoneurosurgery: part III--nanomedicine: targeted nanotherapy, nanosurgery, and progress toward the realization of nanoneurosurgery | journal = Neurosurgery | volume = 58 | issue = 6 | pages = 1009–26 | date = June 2006 | pmid = 16723880 | doi = 10.1227/01.NEU.0000217016.79256.16 | s2cid = 33235348 }}</ref> Nevertheless, progress on innovative materials and patented methodologies have been demonstrated.<ref>{{cite journal | vauthors = Cavalcanti A, Shirinzadeh B, Freitas RA, Kretly LC | title = Medical nanorobot architecture based on nanobioelectronics | journal = Recent Patents on Nanotechnology | volume = 1 | issue = 1 | pages = 1–10 | year = 2007 | pmid = 19076015 | doi = 10.2174/187221007779814745 | s2cid = 9807497 }}</ref><ref>{{cite journal | vauthors = Boukallel M, Gauthier M, Dauge M, Piat E, Abadie J | title = Smart microrobots for mechanical cell characterization and cell convoying | journal = IEEE Transactions on Bio-Medical Engineering | volume = 54 | issue = 8 | pages = 1536–40 | date = August 2007 | pmid = 17694877 | doi = 10.1109/TBME.2007.891171 | s2cid = 1119820 | url = https://hal.archives-ouvertes.fr/hal-00179481/file/Gauthier-00650-2005-R2-electronic_version.pdf }}</ref>
*Productive nanosystems are "systems of nanosystems" which will be complex nanosystems that produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e. atomic) nature of matter and the possibility of exponential growth, this stage is seen as the basis of another industrial revolution. ], one of the architects of the USA's National Nanotechnology Initiative, has proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, progressing from passive nanostructures to active nanodevices to complex ]s and ultimately to productive nanosystems.<ref>{{cite web|url=http://www.nsf.gov/crssprgm/nano/reports/mcr_05-0526_intpersp_nano.pdf |title=International Perspective on Government Nanotechnology Funding in 2005}}</ref> *Productive nanosystems are "systems of nanosystems" could produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e. atomic) nature of matter and the possibility of exponential growth, this stage could form the basis of another industrial revolution. ] proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, progressing from passive nanostructures to active nanodevices to complex ]s and ultimately to productive nanosystems.<ref>{{cite journal | vauthors = Roco MC | title = International Perspective on Government Nanotechnology Funding in 2005. | journal = Journal of Nanoparticle Research | date = December 2005 | volume=7 | issue = 6 |pages=707–712 |url=https://www.nsf.gov/crssprgm/nano/reports/mcr_05-0526_intpersp_nano.pdf |url-status=dead|archive-url=https://web.archive.org/web/20120131175645/http://nsf.gov/crssprgm/nano/reports/mcr_05-0526_intpersp_nano.pdf|archive-date=2012-01-31 |doi=10.1007/s11051-005-3141-5 | bibcode = 2005JNR.....7..707R }}</ref>
*] seeks to design materials whose properties can be easily, reversibly and externally controlled though a fusion of ] and ]. *] seeks to design materials whose properties can be easily, reversibly and externally controlled though a fusion of ] and ].
*Due to the popularity and media exposure of the term nanotechnology, the words ] and ] have been coined in analogy to it, although these are only used rarely and informally. *Due to the popularity and media exposure of the term nanotechnology, the words ] and ] have been coined in analogy to it, although these are used only informally.

===Dimensionality in nanomaterials===
Nanomaterials can be classified in 0D, 1D, 2D and 3D ]. Dimensionality plays a major role in determining the characteristic of nanomaterials including ], ], and ] characteristics. With the decrease in dimensionality, an increase in surface-to-volume ratio is observed. This indicates that smaller dimensional ] have higher surface area compared to 3D nanomaterials. ] have been extensively investigated for ], ], ] and ] applications.


==Tools and techniques== ==Tools and techniques==
] setup. A microfabricated ] with a sharp tip is deflected by features on a sample surface, much like in a ] but on a much smaller scale. A ] beam reflects off the backside of the cantilever into a set of ]s, allowing the deflection to be measured and assembled into an image of the surface.]] ] setup. A microfabricated ] with a sharp tip is deflected by features on a sample surface, much like in a ] but on a much smaller scale. A ] beam reflects off the backside of the cantilever into a set of ]s, allowing the deflection to be measured and assembled into an image of the surface.]]


===Scanning microscopes===
There are several important modern developments. The atomic force microscope (AFM) and the ] (STM) are two early versions of scanning probes that launched nanotechnology. There are other types of ]. Although conceptually similar to the scanning ] developed by ] in 1961 and the ] (SAM) developed by ] and coworkers in the 1970s, newer scanning probe microscopes have much higher resolution, since they are not limited by the wavelength of sound or light.
The ] (AFM) and the ] (STM) are two versions of scanning probes that are used for nano-scale observation. Other types of ] have much higher resolution, since they are not limited by the wavelengths of sound or light.


The tip of a scanning probe can also be used to manipulate nanostructures (a process called positional assembly). ] methodology suggested by Rostislav Lapshin appears to be a promising way to implement these nanomanipulations in automatic mode.<ref name="feature2004">{{cite journal|author=R. V. Lapshin|year=2004|title=Feature-oriented scanning methodology for probe microscopy and nanotechnology|journal=Nanotechnology|volume=15|issue=9|pages=1135–1151|publisher=IOP|location=UK|issn=0957-4484|doi=10.1088/0957-4484/15/9/006|url=http://www.lapshin.fast-page.org/publications.htm#feature2004|format=PDF|bibcode=2004Nanot..15.1135L}}</ref><ref name="fospm2011">{{cite book|author=R. V. Lapshin|year=2011|contribution=Feature-oriented scanning probe microscopy|title=Encyclopedia of Nanoscience and Nanotechnology|editor=H. S. Nalwa|volume=14|pages=105–115|publisher=American Scientific Publishers|location=USA|isbn=1-58883-163-9|url=http://www.lapshin.fast-page.org/publications.htm#fospm2011|format=PDF}}</ref> However, this is still a slow process because of low scanning velocity of the microscope. The tip of a scanning probe can also be used to manipulate nanostructures (positional assembly). ] may be a promising way to implement these nano-scale manipulations via an automatic ].<ref name="feature2004">{{cite journal| vauthors = Lapshin RV |year=2004|title=Feature-oriented scanning methodology for probe microscopy and nanotechnology|journal=Nanotechnology|volume=15|issue=9|pages=1135–51|doi=10.1088/0957-4484/15/9/006|url=http://www.lapshin.fast-page.org/publications.htm#feature2004|format=PDF|bibcode=2004Nanot..15.1135L|s2cid=250913438|url-status=live|archive-url=https://web.archive.org/web/20130909230837/http://www.lapshin.fast-page.org/publications.htm#feature2004|archive-date=2013-09-09}}</ref><ref name="fospm2011">{{cite book| vauthors = Lapshin RV |year=2011|contribution=Feature-oriented scanning probe microscopy|title=Encyclopedia of Nanoscience and Nanotechnology| veditors = Nalwa HS |volume=14|pages=105–115|publisher=American Scientific |isbn=978-1-58883-163-7|url=http://www.lapshin.fast-page.org/publications.htm#fospm2011|format=PDF|url-status=live|archive-url=https://web.archive.org/web/20130909230837/http://www.lapshin.fast-page.org/publications.htm#fospm2011|archive-date=2013-09-09}}</ref> However, this is still a slow process because of low velocity of the microscope.


The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are made. ] is an important technique both for characterization and synthesis. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques.<ref name="feature2004" /><ref name="fospm2011" />
Various techniques of nanolithography such as ], ] dip pen nanolithography, ] or ] were also developed. Lithography is a top-down fabrication technique where a bulk material is reduced in size to nanoscale pattern.


===Lithography===
Another group of nanotechnological techniques include those used for fabrication of ] and ], those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. The precursors of these techniques preceded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology and which were results of nanotechnology research.
Various techniques of lithography, such as ], ], dip pen lithography, ] or ] offer top-down fabrication techniques where a bulk material is reduced to a nano-scale pattern.


Another group of nano-technological techniques include those used for fabrication of ] and ], those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, ], and ], and further including molecular self-assembly techniques such as those employing di-block ]s.<ref name="pmid26295171">{{cite journal | vauthors = Kafshgari MH, Voelcker NH, Harding FJ | title = Applications of zero-valent silicon nanostructures in biomedicine | journal = Nanomedicine | volume = 10 | issue = 16 | pages = 2553–71 | year = 2015 | pmid = 26295171 | doi = 10.2217/nnm.15.91 }}</ref>
The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are made. Scanning probe microscopy is an important technique both for characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques.<ref name="feature2004"/><ref name="fospm2011"/> At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation.


====Bottom-up====
In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, ] and positional assembly. ] is one tool suitable for characterisation of self assembled thin films. Another variation of the bottom-up approach is ] or MBE. Researchers at ] like John R. Arthur. Alfred Y. Cho, and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to lay down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of ].
In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, ] and positional assembly. ] is one tool suitable for characterization of self-assembled thin films. Another variation of the bottom-up approach is ] or MBE. Researchers at ] including ]. ], and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the ] for which the ] was awarded. MBE lays down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of ].


However, new therapeutic products, based on responsive nanomaterials, such as the ultradeformable, stress-sensitive ] vesicles, are under development and already approved for human use in some countries.{{Citation needed|date=August 2008}} Therapeutic products based on responsive ], such as the highly deformable, stress-sensitive ] vesicles, are approved for human use in some countries.<ref>{{cite journal | vauthors = Rajan R, Jose S, Mukund VP, Vasudevan DT | title = Transferosomes - A vesicular transdermal delivery system for enhanced drug permeation | journal = Journal of Advanced Pharmaceutical Technology & Research | volume = 2 | issue = 3 | pages = 138–143 | date = July 2011 | pmid = 22171309 | pmc = 3217704 | doi = 10.4103/2231-4040.85524 | doi-access = free }}</ref>


==Applications== ==Applications==
]'s being made of small ]s ~10 nm in length. Here is a simulation of such a nanowire.]] ] with ]'s being made of small ]s ≈10 nm in length. Here is a simulation of such a nanowire.]]
], which lets ]s roll down the ].]] ], which lets ]s roll down the ].]]
]{{Update section|date=May 2024}}{{Main|List of nanotechnology applications}}


As of August 21, 2008, the ] estimated that over 800 manufacturer-identified nanotech products were publicly available, with new ones hitting the market at a pace of 3–4 per week.<ref name="emergingnano"/> Most applications are "first generation" passive nanomaterials that includes titanium dioxide in sunscreen, cosmetics, surface coatings,<ref>{{cite journal| vauthors = Kurtoglu ME, Longenbach T, Reddington P, Gogotsi Y |year=2011|title=Effect of Calcination Temperature and Environment on Photocatalytic and Mechanical Properties of Ultrathin Sol–Gel Titanium Dioxide Films|journal=Journal of the American Ceramic Society|volume=94|issue=4|pages=1101–8|doi=10.1111/j.1551-2916.2010.04218.x}}</ref> and some food products; Carbon allotropes used to produce ]; silver in ], clothing, disinfectants, and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst.<ref name="americanelements"/>
{{Main|List of nanotechnology applications}}


In the electric car industry, single wall carbon nanotubes (SWCNTs) address key lithium-ion battery challenges, including energy density, charge rate, service life, and cost. SWCNTs connect electrode particles during charge/discharge process, preventing battery premature degradation. Their exceptional ability to wrap active material particles enhanced electrical conductivity and physical properties, setting them apart multi-walled carbon nanotubes and carbon black.<ref>{{cite journal | vauthors = Guo M, Cao Z, Liu Y, Ni Y, Chen X, Terrones M, Wang Y | title = Preparation of Tough, Binder-Free, and Self-Supporting LiFePO<sub>4</sub> Cathode by Using Mono-Dispersed Ultra-Long Single-Walled Carbon Nanotubes for High-Rate Performance Li-Ion Battery | journal = Advanced Science | volume = 10 | issue = 13 | pages = e2207355 | date = May 2023 | pmid = 36905241 | pmc = 10161069 | doi = 10.1002/advs.202207355 }}</ref><ref>{{Cite journal | vauthors = Jimenez NP, Balogh MP, Halalay IC |date= April 2021 |title=High Porosity Single-Phase Silicon Negative Electrode Made with Phase-Inversion |journal=Journal of the Electrochemical Society |volume=168 |issue=4 |pages=040507 |doi=10.1149/1945-7111/abe3f1 |issn=0013-4651|doi-access=free |bibcode= 2021JElS..168d0507J }}</ref><ref>{{Cite web |title=Single wall CNT cells: high energy density anodes & cathodes | publisher = OCSiAl |url=https://tuball.com/nanotubes-in/li-ion-batteries |access-date=2024-07-02 | work = tuball.com |language=en}}</ref>
As of August 21, 2008, the ] estimates that over 800 manufacturer-identified nanotech products are publicly available, with new ones hitting the market at a pace of 3–4 per week.<ref name="emergingnano"/> The project lists all of the products in a publicly accessible online database. Most applications are limited to the use of "first generation" passive nanomaterials which includes titanium dioxide in sunscreen, cosmetics, surface coatings,<ref>{{cite journal | author = Kurtoglu M. E., Longenbach T., Reddington P., Gogotsi Y. | year = 2011 | title = Effect of Calcination Temperature and Environment on Photocatalytic and Mechanical Properties of Ultrathin Sol–Gel Titanium Dioxide Films | url = | journal = Journal of the American Ceramic Society | volume = 94 | issue = 4| pages = 1101–1108 | doi = 10.1111/j.1551-2916.2010.04218.x }}</ref> and some food products; Carbon allotropes used to produce ]; silver in food packaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst.<ref name="americanelements"/>


Further applications allow ]s to last longer, ]s to fly straighter, and even ]s to become more durable and have a harder surface. ]s and ] have been infused with nanotechnology so that they will last longer and keep people cool in the summer. ]s are being infused with silver nanoparticles to heal cuts faster.<ref name="nnin">{{cite web |url= http://www.nnin.org/nnin_nanoproducts.html |title=Nanotechnology Consumer Products |first= |last= |work=nnin.org |year=2010 |accessdate=November 23, 2011}}</ref> Cars are being manufactured with ]s so they may need fewer ]s and less ] to operate in the future.<ref> at NanoandMe.org</ref> ]s and ]s may become cheaper, faster, and contain more memory thanks to nanotechnology.<ref> at NanoandMe.org</ref> Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the ]'s office and at home.<ref> at NanoandMe.org</ref> Further applications allow ]s to last longer, ]s to fly straighter, and ]s to become more durable. ]s and ] have been infused with nanotechnology to last longer and lower temperature in the summer. ]s are infused with silver nanoparticles to heal cuts faster.<ref name="nnin">{{cite web|url=http://www.nnin.org/nnin_nanoproducts.html|title=Nanotechnology Consumer Products|work=National Nanotechnology Infrastructure Network |year=2010|access-date=November 23, 2011|url-status=live|archive-url=https://web.archive.org/web/20120119092143/http://www.nnin.org/nnin_nanoproducts.html|archive-date=January 19, 2012 }}</ref> ]s and ]s may become cheaper, faster, and contain more memory thanks to nanotechnology.<ref>{{cite web|url=http://www.nanoandme.org/nano-products/computing-and-electronics|title=Nano in computing and electronics|archive-url=https://web.archive.org/web/20111114034926/http://www.nanoandme.org/nano-products/computing-and-electronics/|archive-date=2011-11-14|website=NanoandMe.org}}</ref> Also, to build structures for on chip computing with light, for example on chip optical quantum information processing, and picosecond transmission of information.<ref>{{cite journal | vauthors = Mayer B, Janker L, Loitsch B, Treu J, Kostenbader T, Lichtmannecker S, Reichert T, Morkötter S, Kaniber M, Abstreiter G, Gies C, Koblmüller G, Finley JJ | title = Monolithically Integrated High-β Nanowire Lasers on Silicon | journal = Nano Letters | volume = 16 | issue = 1 | pages = 152–156 | date = January 2016 | pmid = 26618638 | doi = 10.1021/acs.nanolett.5b03404 | bibcode = 2016NanoL..16..152M }}</ref>


Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the doctors' offices and at homes.<ref>{{cite web|url=http://www.nanoandme.org/nano-products/medical|title=Nano in medicine|archive-url=https://web.archive.org/web/20111114035018/http://www.nanoandme.org/nano-products/medical/|archive-date=2011-11-14|website=NanoandMe.org}}</ref> Cars use ]s in such ways that car parts require fewer ]s during manufacturing and less ] to operate in the future.<ref>{{cite web|url=http://www.nanoandme.org/nano-products/transport/|title=Nano in transport|archive-url=https://web.archive.org/web/20111029130940/http://www.nanoandme.org/nano-products/transport/|archive-date=2011-10-29|website=NanoandMe.org}}</ref>
The ] (a major distributor for nanotechnology research in the United States) funded researcher David Berube to study the field of nanotechnology. His findings are published in the monograph Nano-Hype: The Truth Behind the Nanotechnology Buzz. This study concludes that much of what is sold as “nanotechnology” is in fact a recasting of straightforward materials science, which is leading to a “nanotech industry built solely on selling nanotubes, nanowires, and the like” which will “end up with a few suppliers selling low margin products in huge volumes." Further applications which require actual manipulation or arrangement of nanoscale components await further research. Though technologies branded with the term 'nano' are sometimes little related to and fall far short of the most ambitious and transformative technological goals of the sort in molecular manufacturing proposals, the term still connotes such ideas. According to Berube, there may be a danger that a "nano bubble" will form, or is forming already, from the use of the term by scientists and entrepreneurs to garner funding, regardless of interest in the transformative possibilities of more ambitious and far-sighted work.<ref>{{cite book |last=Berube |first=David |title=Nano-Hype: The Truth Behind the Nanotechnology Buzz |location=Amherst, NY |publisher=Prometheus Books |year=2006 |url=http://www.prometheusbooks.com/index.php?main_page=product_info&products_id=1822/ }}</ref>

Nanoencapsulation involves the enclosure of active substances within carriers. Typically, these carriers offer advantages, such as enhanced bioavailability, controlled release, targeted delivery, and protection of the encapsulated substances. In the medical field, nanoencapsulation plays a significant role in ]. It facilitates more efficient drug administration, reduces side effects, and increases treatment effectiveness. Nanoencapsulation is particularly useful for improving the bioavailability of poorly water-soluble drugs, enabling controlled and sustained drug release, and supporting the development of targeted therapies. These features collectively contribute to advancements in medical treatments and patient care.<ref>{{cite journal | vauthors = Kumari A, Singla R, Guliani A, Yadav SK | title = Nanoencapsulation for drug delivery | journal = EXCLI Journal | volume = 13 | pages = 265–286 | date = March 2014 | pmid = 26417260 | pmc = 4464443 }}</ref><ref>{{Cite web | vauthors = Suganya V, Anuradha V |date=March 2017 |title=Microencapsulation and Nanoencapsulation: A Review |url=https://www.researchgate.net/publication/318501373 |access-date=28 October 2023 |website=ResearchGate}}</ref>

Nanotechnology may play role in ]. When designing scaffolds, researchers attempt to mimic the nanoscale features of a ]'s microenvironment to direct its differentiation down a suitable lineage.<ref>{{cite journal | vauthors = Cassidy JW | title = Nanotechnology in the Regeneration of Complex Tissues | journal = Bone and Tissue Regeneration Insights | volume = 5 | pages = 25–35 | date = November 2014 | pmid = 26097381 | pmc = 4471123 | doi = 10.4137/BTRI.S12331 }}</ref> For example, when creating scaffolds to support bone growth, researchers may mimic ] resorption pits.<ref>{{cite journal | vauthors = Cassidy JW, Roberts JN, Smith CA, Robertson M, White K, Biggs MJ, Oreffo RO, Dalby MJ | title = Osteogenic lineage restriction by osteoprogenitors cultured on nanometric grooved surfaces: the role of focal adhesion maturation | journal = Acta Biomaterialia | volume = 10 | issue = 2 | pages = 651–660 | date = February 2014 | pmid = 24252447 | pmc = 3907683 | doi = 10.1016/j.actbio.2013.11.008 | url = http://eprints.soton.ac.uk/367171/ | url-status = live | archive-url = https://web.archive.org/web/20170830234634/https://eprints.soton.ac.uk/367171/ | author-link8 = Matthew Dalby | archive-date = 2017-08-30 }}</ref>

Researchers used ]-based nanobots capable of carrying out logic functions to target drug delivery in cockroaches.<ref>{{cite journal | vauthors = Amir Y, Ben-Ishay E, Levner D, Ittah S, Abu-Horowitz A, Bachelet I | title = Universal computing by DNA origami robots in a living animal | journal = Nature Nanotechnology | volume = 9 | issue = 5 | pages = 353–357 | date = May 2014 | pmid = 24705510 | pmc = 4012984 | doi = 10.1038/nnano.2014.58 | bibcode = 2014NatNa...9..353A }}</ref>

A nano bible (a .5mm2 silicon chip) was created by the ] in order to increase youth interest in nanotechnology.<ref>{{Cite web |date=2015-11-04 |title=Technion Nano Bible, world's smallest, displayed at Smithsonian |url=https://www.jpost.com/business-and-innovation/tech/technion-nano-bible-worlds-smallest-displayed-at-smithsonian-432038 |access-date=2024-06-25 |website=The Jerusalem Post {{!}} JPost.com |language=en}}</ref>


==Implications== ==Implications==
{{Main|Implications of nanotechnology}} {{Main|Implications of nanotechnology}}


An area of concern is the effect that industrial-scale manufacturing and use of nanomaterials would have on human health and the environment, as suggested by ] research. For these reasons, some groups advocate that nanotechnology be regulated by governments. Others counter that overregulation would stifle scientific research and the development of beneficial innovations. ] research agencies, such as the ] are actively conducting research on potential health effects stemming from exposures to nanoparticles.<ref name ="niosh">{{Cite web|url=http://www.cdc.gov/niosh/topics/nanotech/|title=CDC - Nanotechnology - NIOSH Workplace Safety and Health Topic|publisher=National Institute for Occupational Safety and Health |date=June 15, 2012 |accessdate=2012-08-24}}</ref><ref name ="nioshnano">{{Cite web|url=http://www.cdc.gov/niosh/docs/2013-101/|title=CDC - NIOSH Publications and Products - Filling the Knowledge Gaps for Safe Nanotechnology in the Workplace|publisher=National Institute for Occupational Safety and Health |date=November 7, 2012 |accessdate=2012-11-08}}</ref> One concern is the effect that industrial-scale manufacturing and use of nanomaterials will have on human health and the environment, as suggested by ] research. For these reasons, some groups advocate that nanotechnology be regulated. However, regulation might stifle scientific research and the development of beneficial innovations. ] research agencies, such as the ] research potential health effects stemming from exposures to nanoparticles.<ref name="niosh">{{cite web|url=https://www.cdc.gov/niosh/topics/nanotech/?s_cid=3ni7d2ms082915|title=Nanotechnology |work=NIOSH Workplace Safety and Health Topic|publisher=National Institute for Occupational Safety and Health|date=June 15, 2012|access-date=2012-08-24|url-status=live|archive-url=https://web.archive.org/web/20150904005250/http://www.cdc.gov/niosh/topics/nanotech/?s_cid=3ni7d2ms082915|archive-date=September 4, 2015}}</ref><ref name="nioshnano">{{Cite journal|url=https://www.cdc.gov/niosh/docs/2013-101/|journal=NIOSH Publications and Products |title=Filling the Knowledge Gaps for Safe Nanotechnology in the Workplace|publisher=National Institute for Occupational Safety and Health|date=November 7, 2012|access-date=2012-11-08|url-status=live|archive-url=https://web.archive.org/web/20121111211819/http://www.cdc.gov/niosh/docs/2013-101/|archive-date=November 11, 2012|doi=10.26616/NIOSHPUB2013101|doi-access=free |id=2013-101}}</ref>


Some nanoparticle products may have ]. Researchers have discovered that ] silver nanoparticles used in socks to reduce foot odor are being released in the wash.<ref>Lubick, N. (2008). {{dead link|date=June 2012}}</ref> These particles are then flushed into the waste water stream and may destroy bacteria which are critical components of natural ecosystems, farms, and waste treatment processes.<ref>Murray R.G.E., Advances in Bacterial Paracrystalline Surface Layers (Eds.: T. J. Beveridge, S. F. Koval). Plenum pp. 3 ± 9. </ref> Nanoparticle products may have ]. Researchers have discovered that ] silver nanoparticles used in socks to reduce foot odor are released in the wash.<ref>{{cite journal | vauthors = Lubick N | title = Silver socks have cloudy lining | journal = Environmental Science & Technology | volume = 42 | issue = 11 | pages = 3910 | date = June 2008 | pmid = 18589943 | doi = 10.1021/es0871199 | s2cid = 26887347 | bibcode = 2008EnST...42.3910L }}</ref> These particles are then flushed into the wastewater stream and may destroy bacteria that are critical components of natural ecosystems, farms, and waste treatment processes.<ref>{{cite book | vauthors = Murray RG | chapter = A Perspective on S-Layer Research | date = 1993 | veditors = Beveridge TJ, Koval SF | title = Advances in Bacterial Paracrystalline Surface Layers | publisher = Plenum Press | isbn = 978-0-306-44582-8 | doi = 10.1007/978-1-4757-9032-0_1 | pages = 3–9 }}</ref>


Public deliberations on ] in the US and UK carried out by the Center for Nanotechnology in Society found that participants were more positive about nanotechnologies for energy applications than for health applications, with health applications raising moral and ethical dilemmas such as cost and availability.<ref name="harthorn">Barbara Herr Harthorn, Nanotechnology Today, January 23, 2009.</ref> Public deliberations on ] in the US and UK carried out by the Center for Nanotechnology in Society found that participants were more positive about nanotechnologies for energy applications than for health applications, with health applications raising moral and ethical dilemmas such as cost and availability.<ref name="harthorn">{{cite web| vauthors = Harthorn BH |date=2009-01-23|url=http://nanotechnologytoday.blogspot.com/2009/01/people-in-us-and-uk-show-strong.html|title=People in the US and the UK show strong similarities in their attitudes toward nanotechnologies|archive-url=https://web.archive.org/web/20110823001736/http://nanotechnologytoday.blogspot.com/2009/01/people-in-us-and-uk-show-strong.html|archive-date=2011-08-23|website=Nanotechnology Today}}</ref>


Experts, including director of the Woodrow Wilson Center's Project on Emerging Nanotechnologies David Rejeski, have testified<ref> Project on Emerging Nanotechnologies. Retrieved on 2008-3-7.</ref> that successful commercialization depends on adequate oversight, risk research strategy, and public engagement. ] is currently the only city in the United States to regulate nanotechnology;<ref></ref> ] in 2008 considered enacting a similar law,<ref></ref> but ultimately rejected it.<ref></ref> Relevant for both research on and application of nanotechnologies, the ] of nanotechnology is contested.<ref>Encyclopedia of Nanoscience and Society, edited by David H. Guston, Sage Publications, 2010; see Articles on Insurance and Reinsurance (by I. Lippert).</ref> Without state ], the availability of private insurance for potential damages is seen as necessary to ensure that burdens are not socialised implicitly. Experts, including director of the Woodrow Wilson Center's Project on Emerging Nanotechnologies David Rejeski, testified<ref>{{cite web|url=http://www.nanotechproject.org/news/archive/successful_commercialization_depends_on/|title=Testimony of David Rejeski for U.S. Senate Committee on Commerce, Science and Transportation|archive-url=https://web.archive.org/web/20080408064825/http://www.nanotechproject.org/news/archive/successful_commercialization_depends_on/|archive-date=2008-04-08|work=Project on Emerging Nanotechnologies|access-date=2008-03-07}}</ref> that commercialization depends on adequate oversight, risk research strategy, and public engagement. As of 206 ] was the only US city to regulate nanotechnology.<ref>{{cite news| vauthors = DelVecchio R |date=2006-11-24|url=http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/11/24/MNGP9MJ4KI1.DTL|title=Berkeley considering need for nano safety|archive-url=https://web.archive.org/web/20100902211655/http://articles.sfgate.com/2006-11-24/news/17319373_1_hazardous-materials-nanoparticles-uc-berkeley|archive-date=2010-09-02|website=SFGate }}</ref>


===Health and environmental concerns=== ===Health and environmental concerns===
]
{{Main|Health implications of nanotechnology|Environmental implications of nanotechnology}}
{{Main|Health and safety hazards of nanomaterials|Pollution from nanomaterials}}
Nanofibers are used in several areas and in different products, in everything from aircraft wings to tennis rackets. Inhaling airborne nanoparticles and nanofibers may lead to a number of ]s, e.g. ].<ref>{{cite journal|url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2322933/|title=The significance of nano particles in particle-induced pulmonary fibrosis|author1=James D Byrne|author2=John A Baugh|journal=McGill Journal of Medicine|year=2008|volume=11|pages=43–50}}</ref> Researchers have found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response<ref>Elder, A. (2006). </ref> and that nanoparticles induce skin aging through oxidative stress in hairless mice.<ref>{{cite journal |pmid=19501137 |year=2009 |last1=Wu |first1=J |last2=Liu |first2=W |last3=Xue |first3=C |last4=Zhou |first4=S |last5=Lan |first5=F |last6=Bi |first6=L |last7=Xu |first7=H |last8=Yang |first8=X |last9=Zeng |first9=FD |displayauthors=8 |title=Toxicity and penetration of TiO2 nanoparticles in hairless mice and porcine skin after subchronic dermal exposure |volume=191 |issue=1 |pages=1–8 |doi=10.1016/j.toxlet.2009.05.020|journal=]}}</ref><ref>{{cite journal |pmid=19836437 |year=2010 |last1=Jonaitis |first1=TS |last2=Card |first2=JW |last3=Magnuson|first3=B|title=Concerns regarding nano-sized titanium dioxide dermal penetration and toxicity study |volume=192 |issue=2 |pages=268–9 |doi=10.1016/j.toxlet.2009.10.007|journal=Toxicology letters}}</ref>
Inhaling airborne nanoparticles and nanofibers may contribute to ]s, e.g. ].<ref>{{cite journal | vauthors = Byrne JD, Baugh JA | title = The significance of nanoparticles in particle-induced pulmonary fibrosis | journal = McGill Journal of Medicine | volume = 11 | issue = 1 | pages = 43–50 | date = January 2008 | pmid = 18523535 | pmc = 2322933 }}</ref> Researchers found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response<ref>{{cite web| vauthors = Elder A |date=2006-08-03|url=http://www.urmc.rochester.edu/pr/news/story.cfm?id=1191|title=Tiny Inhaled Particles Take Easy Route from Nose to Brain|website=University of Rochester Medical Center|archive-url=https://web.archive.org/web/20150123193204/http://www.urmc.rochester.edu/news/story/index.cfm?id=1191|archive-date=2015-01-23}}</ref> and that nanoparticles induce skin aging through oxidative stress in hairless mice.<ref>{{cite journal | vauthors = Wu J, Liu W, Xue C, Zhou S, Lan F, Bi L, Xu H, Yang X, Zeng FD | title = Toxicity and penetration of TiO2 nanoparticles in hairless mice and porcine skin after subchronic dermal exposure | journal = Toxicology Letters | volume = 191 | issue = 1 | pages = 1–8 | date = December 2009 | pmid = 19501137 | doi = 10.1016/j.toxlet.2009.05.020 }}</ref><ref>{{cite journal | vauthors = Jonaitis TS, Card JW, Magnuson B | title = Concerns regarding nano-sized titanium dioxide dermal penetration and toxicity study | journal = Toxicology Letters | volume = 192 | issue = 2 | pages = 268–269 | date = February 2010 | pmid = 19836437 | doi = 10.1016/j.toxlet.2009.10.007 }}</ref>


A two-year study at UCLA's School of Public Health found lab mice consuming nano-titanium dioxide showed DNA and chromosome damage to a degree "linked to all the big killers of man, namely cancer, heart disease, neurological disease and aging".<ref>Schneider, Andrew, , March 24, 2010.</ref> A two-year study at ] found lab mice consuming nano-titanium dioxide showed DNA and chromosome damage to a degree "linked to all the big killers of man, namely cancer, heart disease, neurological disease and aging".<ref>{{cite web| vauthors = Schneider A |date=2010-03-24|url=http://www.aolnews.com/nanotech/article/amid-nanotechs-dazzling-promise-health-risks-grow/19401235|title=Amid Nanotech's Dazzling Promise, Health Risks Grow|archive-url=https://web.archive.org/web/20100326130438/http://www.aolnews.com/nanotech/article/amid-nanotechs-dazzling-promise-health-risks-grow/19401235|archive-date=2010-03-26|website=AOL News}}</ref>


A '']'' study suggested that some forms of ]s could be as harmful as ] if inhaled in sufficient quantities. ] of the ] in Edinburgh, Scotland, who contributed to the article on ]s said "We know that some of them probably have the potential to cause mesothelioma. So those sorts of materials need to be handled very carefully."<ref>{{cite news| vauthors = Weiss R |date=2008|url=https://www.washingtonpost.com/wp-dyn/content/article/2008/05/20/AR2008052001331.html?hpid=sec-health&sid=ST2008052100104|title=Effects of Nanotubes May Lead to Cancer, Study Says|newspaper=] |archive-url=https://web.archive.org/web/20110629001411/http://www.washingtonpost.com/wp-dyn/content/article/2008/05/20/AR2008052001331.html?hpid=sec-health&sid=ST2008052100104|archive-date=2011-06-29}}</ref> In the absence of specific regulation forthcoming from governments, Paull and Lyons (2008) have called for an exclusion of engineered nanoparticles in food.<ref>{{cite journal| vauthors = Paull J, Lyons K |year=2008 |url=http://orgprints.org/13569/1/13569.pdf|title=Nanotechnology: The Next Challenge for Organics|journal=Journal of Organic Systems|volume=3|pages=3–22|url-status=live|archive-url=https://web.archive.org/web/20110718172822/http://orgprints.org/13569/1/13569.pdf|archive-date=2011-07-18}}</ref> A newspaper article reports that workers in a paint factory developed serious lung disease and nanoparticles were found in their lungs.<ref>{{cite news|title=Nanoparticles used in paint could kill, research suggests|newspaper=Telegraph|url=https://www.telegraph.co.uk/health/healthnews/6016639/Nanoparticles-used-in-paint-could-kill-research-suggests.html|location=London| vauthors = Smith R |date=August 19, 2009|access-date=May 19, 2010|url-status=dead|archive-url=https://web.archive.org/web/20100315162044/http://www.telegraph.co.uk/health/healthnews/6016639/Nanoparticles-used-in-paint-could-kill-research-suggests.html|archive-date=March 15, 2010 }}</ref><ref>{{cite news|url=https://www.bbc.com/news/health-19355196|title=Nanofibres 'may pose health risk'|archive-url=https://web.archive.org/web/20120825143122/http://www.bbc.co.uk/news/health-19355196|archive-date=2012-08-25|website=BBC News|date=2012-08-24}}</ref><ref>{{cite journal | vauthors = Schinwald A, Murphy FA, Prina-Mello A, Poland CA, Byrne F, Movia D, Glass JR, Dickerson JC, Schultz DA, Jeffree CE, Macnee W, Donaldson K | title = The threshold length for fiber-induced acute pleural inflammation: shedding light on the early events in asbestos-induced mesothelioma | journal = Toxicological Sciences | volume = 128 | issue = 2 | pages = 461–470 | date = August 2012 | pmid = 22584686 | doi = 10.1093/toxsci/kfs171 | doi-access = free }}</ref><ref>{{cite web | vauthors = Stix G | date = July 2007 |url=https://www.scientificamerican.com/article/chronic-inflammation-cancer/ |title=Is Chronic Inflammation the Key to Unlocking the Mysteries of Cancer?| work = ]}}</ref>
A major study published more recently in ] suggests some forms of carbon nanotubes – a poster child for the “nanotechnology revolution” – could be as harmful as ] if inhaled in sufficient quantities. ] of the Institute of Occupational Medicine in Edinburgh, Scotland, who contributed to the article on ] said "We know that some of them probably have the potential to cause mesothelioma. So those sorts of materials need to be handled very carefully."<ref>Weiss, R. (2008).
</ref> In the absence of specific regulation forthcoming from governments, Paull and Lyons (2008) have called for an exclusion of engineered nanoparticles in food.<ref>{{cite journal|author=Paull, J. & Lyons, K. |year=2008|url=http://orgprints.org/13569/1/13569.pdf|title= Nanotechnology: The Next Challenge for Organics|journal=Journal of Organic Systems|volume=3|pages=3–22}}</ref> A newspaper article reports that workers in a paint factory developed serious lung disease and nanoparticles were found in their lungs.<ref>{{cite news|title=Nanoparticles used in paint could kill, research suggests |publisher=Telegraph |url=http://www.telegraph.co.uk/health/healthnews/6016639/Nanoparticles-used-in-paint-could-kill-research-suggests.html| location=London | first=Rebecca | last=Smith | date=August 19, 2009 | accessdate=May 19, 2010}}</ref><ref name=bbcfibre00>, 2012-08-24</ref><ref>, 2012-05-12</ref><ref>, 2008-11-09</ref>


==Regulation== ==Regulation==
{{Main|Regulation of nanotechnology}} {{Main|Regulation of nanotechnology}}


Calls for tighter regulation of nanotechnology have occurred alongside a growing debate related to the human health and safety risks of nanotechnology.<ref>{{cite web |url=http://www.nanolabweb.com/index.cfm/action/main.default.viewArticle/articleID/290/CFID/3564274/CFTOKEN/43473772/index.html |title=Nanobiotechnology Regulation: A Proposal for Self-Regulation with Limited Oversight Calls for tighter regulation of nanotechnology have accompanied a debate related to human health and safety risks.<ref>{{cite journal |url= http://www.nanolabweb.com/index.cfm/action/main.default.viewArticle/articleID/290/CFID/3564274/CFTOKEN/43473772/index.html| title= Nanobiotechnology Regulation: A Proposal for Self-Regulation with Limited Oversight| vauthors = Rollins K | publisher = Nems Mems Works, LLC | journal = Nanotechnology Law Business | volume = 6 | issue = 2 |access-date=2 September 2010|url-status=live|archive-url=https://web.archive.org/web/20110714153112/http://www.nanolabweb.com/index.cfm/action/main.default.viewArticle/articleID/290/CFID/3564274/CFTOKEN/43473772/index.html|archive-date=14 July 2011}}</ref> Some regulatory agencies cover some nanotechnology products and processes – by "bolting on" nanotechnology to existing regulations – leaving clear gaps.<ref>{{cite journal|vauthors=Bowman D, Hodge G|title=Nanotechnology: Mapping the Wild Regulatory Frontier|journal=Futures|volume=38|pages=1060–73|year=2006|doi=10.1016/j.futures.2006.02.017|issue=9}}</ref> Davies proposed a road map describing steps to deal with these shortcomings.<ref>{{cite web| vauthors = Davies JC |date=2008|url=http://www.nanotechproject.org/publications/archive/pen13/|title=Nanotechnology Oversight: An Agenda for the Next Administration|archive-url=https://web.archive.org/web/20081120154647/http://www.nanotechproject.org/publications/archive/pen13/|archive-date=2008-11-20}}.</ref>
|author=Kevin Rollins (Nems Mems Works, LLC) |date= |work=Volume 6 – Issue 2|publisher= |accessdate=2 September 2010}}</ref> There is significant debate about who is responsible for the regulation of nanotechnology. Some regulatory agencies currently cover some nanotechnology products and processes (to varying degrees) – by “bolting on” nanotechnology to existing regulations – there are clear gaps in these regimes.<ref>{{cite journal |author=Bowman D, and Hodge G|title=Nanotechnology: Mapping the Wild Regulatory Frontier |journal=Futures |volume=38 |pages=1060–1073 |year=2006|doi=10.1016/j.futures.2006.02.017 |issue=9}}</ref> Davies (2008) has proposed a regulatory road map describing steps to deal with these shortcomings.<ref>Davies, J. C. (2008). .</ref>


Stakeholders concerned by the lack of a regulatory framework to assess and control risks associated with the release of nanoparticles and nanotubes have drawn parallels with ] ("mad cow" disease), ], genetically modified food,<ref>{{cite journal |author=Rowe G, Horlick-Jones T, Walls J, Pidgeon N, |title= Difficulties in evaluating public engagement initiatives: reflections on an evaluation of the UK GM Nation? |journal=. |volume=14 |year=2005 |page=333}}</ref> nuclear energy, reproductive technologies, biotechnology, and ]. Dr. Andrew Maynard, chief science advisor to the Woodrow Wilson Center’s Project on Emerging Nanotechnologies, concludes that there is insufficient funding for human health and safety research, and as a result there is currently limited understanding of the human health and safety risks associated with nanotechnology.<ref>Maynard, A.. (2008-4-16). Retrieved on 2008-11-24.</ref> As a result, some academics have called for stricter application of the ], with delayed marketing approval, enhanced labelling and additional safety data development requirements in relation to certain forms of nanotechnology.<ref>Faunce TA et al. Sunscreen Safety: The Precautionary Principle, Andrew Maynard, chief science advisor to the Woodrow Wilson Center's Project on Emerging Nanotechnologies, reported insufficient funding for human health and safety research, and as a result inadequate understanding of human health and safety risks.<ref>{{cite web| vauthors = Maynard A |url=http://www.science.house.gov/publications/Testimony.aspx?TID=12957|title=Testimony by Dr. Andrew Maynard for the U.S. House Committee on Science and Technology|date=2008-04-16|access-date=2008-11-24|archive-url=https://web.archive.org/web/20101205122135/http://science.house.gov/publications/Testimony.aspx?TID=12957|archive-date=2010-12-05}}</ref> Some academics called for stricter application of the ], slowing marketing approval, enhanced labelling and additional safety data.<ref>{{Cite journal|doi=10.1007/s11569-008-0041-z|title=Sunscreen Safety: The Precautionary Principle, the Australian Therapeutic Goods Administration and Nanoparticles in Sunscreens|journal=NanoEthics|volume=2|issue=3|pages=231–240 |year=2008 | vauthors = Faunce T, Murray K, Nasu H, Bowman D |s2cid=55719697 }}</ref>
The Australian Therapeutic Goods Administration and Nanoparticles in Sunscreens Nanoethics (2008) 2:231–240 DOI 10.1007/s11569-008-0041-z. {{cite web |url=http://law.anu.edu.au/StaffUploads/236-Nanoethics%20Sunscreens%202008.pdf |title=Sunscreen Safety: The Precautionary Principle, The Australian Therapeutic Goods Administration and Nanoparticles in Sunscreens |author=Thomas Faunce & Katherine Murray & Hitoshi Nasu & Diana Bowman |date=published online: 24 July 2008 |work= |publisher=Springer Science + Business Media B.V |accessdate=18 June 2009 }}</ref>


The Royal Society report<ref name="royalsociety"/> identified a risk of nanoparticles or nanotubes being released during disposal, destruction and recycling, and recommended that “manufacturers of products that fall under extended producer responsibility regimes such as end-of-life regulations publish procedures outlining how these materials will be managed to minimize possible human and environmental exposure” (p. xiii). Reflecting the challenges for ensuring responsible life cycle regulation, the has proposed that standards for nanotechnology research and development should be integrated across consumer, worker and environmental standards. They also propose that ]s and other citizen groups play a meaningful role in the development of these standards. A Royal Society report identified a risk of nanoparticles or nanotubes being released during disposal, destruction and recycling, and recommended that "manufacturers of products that fall under ] regimes such as end-of-life regulations publish procedures outlining how these materials will be managed to minimize possible human and environmental exposure".<ref name="royalsociety" />

The Center for Nanotechnology in Society has found that people respond differently to nanotechnologies based upon application – with participants in ] more positive about nanotechnologies for energy than health applications – suggesting that any public calls for nano regulations may differ by technology sector.<ref name="harthorn"/>


==See also== ==See also==
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Latest revision as of 12:20, 8 January 2025

Technology with features near one nanometer

For the materials science journal, see Nanotechnology (journal). For other uses of "Nanotech", see Nanotech (disambiguation).

Fullerene nanogears
Part of a series of articles on
Nanotechnology
Impact and applications
Nanomaterials
Molecular self-assembly
Nanoelectronics
Nanometrology
Molecular nanotechnology

Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing properties of matter. This definition of nanotechnology includes all types of research and technologies that deal with these special properties. It is common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to research and applications whose common trait is scale. An earlier understanding of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabricating macroscale products, now referred to as molecular nanotechnology.

Nanotechnology defined by scale includes fields of science such as surface science, organic chemistry, molecular biology, semiconductor physics, energy storage, engineering, microfabrication, and molecular engineering. The associated research and applications range from extensions of conventional device physics to molecular self-assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale.

Nanotechnology may be able to create new materials and devices with diverse applications, such as in nanomedicine, nanoelectronics, biomaterials energy production, and consumer products. However, nanotechnology raises issues, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on global economics, as well as various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.

Origins

Main article: History of nanotechnology

The concepts that seeded nanotechnology were first discussed in 1959 by physicist Richard Feynman in his talk There's Plenty of Room at the Bottom, in which he described the possibility of synthesis via direct manipulation of atoms.

Comparison of nanomaterials sizes

The term "nano-technology" was first used by Norio Taniguchi in 1974, though it was not widely known. Inspired by Feynman's concepts, K. Eric Drexler used the term "nanotechnology" in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, which proposed the idea of a nanoscale "assembler" that would be able to build a copy of itself and of other items of arbitrary complexity with atom-level control. Also in 1986, Drexler co-founded The Foresight Institute to increase public awareness and understanding of nanotechnology concepts and implications.

The emergence of nanotechnology as a field in the 1980s occurred through the convergence of Drexler's theoretical and public work, which developed and popularized a conceptual framework, and high-visibility experimental advances that drew additional attention to the prospects. In the 1980s, two breakthroughs sparked the growth of nanotechnology. First, the invention of the scanning tunneling microscope in 1981 enabled visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope's developers Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory received a Nobel Prize in Physics in 1986. Binnig, Quate and Gerber also invented the analogous atomic force microscope that year.

Buckminsterfullerene C60, also known as the buckyball, is a representative member of the carbon structures known as fullerenes. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.

Second, fullerenes (buckyballs) were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl, who together won the 1996 Nobel Prize in Chemistry. C60 was not initially described as nanotechnology; the term was used regarding subsequent work with related carbon nanotubes (sometimes called graphene tubes or Bucky tubes) which suggested potential applications for nanoscale electronics and devices. The discovery of carbon nanotubes is largely attributed to Sumio Iijima of NEC in 1991, for which Iijima won the inaugural 2008 Kavli Prize in Nanoscience.

In the early 2000s, the field garnered increased scientific, political, and commercial attention that led to both controversy and progress. Controversies emerged regarding the definitions and potential implications of nanotechnologies, exemplified by the Royal Society's report on nanotechnology. Challenges were raised regarding the feasibility of applications envisioned by advocates of molecular nanotechnology, which culminated in a public debate between Drexler and Smalley in 2001 and 2003.

Meanwhile, commercial products based on advancements in nanoscale technologies began emerging. These products were limited to bulk applications of nanomaterials and did not involve atomic control of matter. Some examples include the Silver Nano platform for using silver nanoparticles as an antibacterial agent, nanoparticle-based sunscreens, carbon fiber strengthening using silica nanoparticles, and carbon nanotubes for stain-resistant textiles.

Governments moved to promote and fund research into nanotechnology, such as American the National Nanotechnology Initiative, which formalized a size-based definition of nanotechnology and established research funding, and in Europe via the European Framework Programmes for Research and Technological Development.

By the mid-2000s scientific attention began to flourish. Nanotechnology roadmaps centered on atomically precise manipulation of matter and discussed existing and projected capabilities, goals, and applications.

Fundamental concepts

Nanotechnology is the science and engineering of functional systems at the molecular scale. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up making complete, high-performance products.

One nanometer (nm) is one billionth, or 10, of a meter. By comparison, typical carbon–carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12–0.15 nm, and DNA's diameter is around 2 nm. On the other hand, the smallest cellular life forms, the bacteria of the genus Mycoplasma, are around 200 nm in length. By convention, nanotechnology is taken as the scale range 1 to 100 nm, following the definition used by the American National Nanotechnology Initiative. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which have an approximately ,25 nm kinetic diameter). The upper limit is more or less arbitrary, but is around the size below which phenomena not observed in larger structures start to become apparent and can be made use of. These phenomena make nanotechnology distinct from devices that are merely miniaturized versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description of microtechnology.

To put that scale in another context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth.

Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.

Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved to provide nanotechnology's scientific foundation.

Larger to smaller: a materials perspective

Image of reconstruction on a clean Gold(100) surface, as visualized using scanning tunneling microscopy. The positions of the individual atoms composing the surface are visible.
Main article: Nanomaterials

Several phenomena become pronounced as system size. These include statistical mechanical effects, as well as quantum mechanical effects, for example, the "quantum size effect" in which the electronic properties of solids alter along with reductions in particle size. Such effects do not apply at macro or micro dimensions. However, quantum effects can become significant when nanometer scales. Additionally, physical (mechanical, electrical, optical, etc.) properties change versus macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal, and catalytic properties of materials. Diffusion and reactions can be different as well. Systems with fast ion transport are referred to as nanoionics. The mechanical properties of nanosystems are of interest in research.

Simple to complex: a molecular perspective

Main article: Molecular self-assembly

Modern synthetic chemistry can prepare small molecules of almost any structure. These methods are used to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble single molecules into supramolecular assemblies consisting of many molecules arranged in a well-defined manner.

These approaches utilize the concepts of molecular self-assembly and/or supramolecular chemistry to automatically arrange themselves into a useful conformation through a bottom-up approach. The concept of molecular recognition is important: molecules can be designed so that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson–Crick basepairing rules are a direct result of this, as is the specificity of an enzyme targeting a single substrate, or the specific folding of a protein. Thus, components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.

Such bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, many examples of self-assembly based on molecular recognition in exist in biology, most notably Watson–Crick basepairing and enzyme-substrate interactions.

Molecular nanotechnology: a long-term view

Main article: Molecular nanotechnology

Molecular nanotechnology, sometimes called molecular manufacturing, concerns engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology is especially associated with molecular assemblers, machines that can produce a desired structure or device atom-by-atom using the principles of mechanosynthesis. Manufacturing in the context of productive nanosystems is not related to conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.

When Drexler independently coined and popularized the term "nanotechnology", he envisioned manufacturing technology based on molecular machine systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated molecular machines were possible: biology was full of examples of sophisticated, stochastically optimized biological machines.

Drexler and other researchers have proposed that advanced nanotechnology ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification. The physics and engineering performance of exemplar designs were analyzed in Drexler's book Nanosystems: Molecular Machinery, Manufacturing, and Computation.

In general, assembling devices on the atomic scale requires positioning atoms on other atoms of comparable size and stickiness. Carlo Montemagno's view is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Richard Smalley argued that mechanosynthesis was impossible due to difficulties in mechanically manipulating individual molecules.

This led to an exchange of letters in the ACS publication Chemical & Engineering News in 2003. Though biology clearly demonstrates that molecular machines are possible, non-biological molecular machines remained in their infancy. Alex Zettl and colleagues at Lawrence Berkeley Laboratories and UC Berkeley constructed at least three molecular devices whose motion is controlled via changing voltage: a nanotube nanomotor, a molecular actuator, and a nanoelectromechanical relaxation oscillator.

Ho and Lee at Cornell University in 1999 used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal and chemically bound the CO to the Fe by applying a voltage.

Research

Graphical representation of a rotaxane, useful as a molecular switch
This DNA tetrahedron is an artificially designed nanostructure of the type made in the field of DNA nanotechnology. Each edge of the tetrahedron is a 20 base pair DNA double helix, and each vertex is a three-arm junction.
Rotating view of C60, one kind of fullerene
This device transfers energy from nano-thin layers of quantum wells to nanocrystals above them, causing the nanocrystals to emit visible light.

Nanomaterials

Many areas of science develop or study materials having unique properties arising from their nanoscale dimensions.

Bottom-up approaches

The bottom-up approach seeks to arrange smaller components into more complex assemblies.

  • DNA nanotechnology utilizes Watson–Crick basepairing to construct well-defined structures out of DNA and other nucleic acids.
  • Approaches from the field of "classical" chemical synthesis (inorganic and organic synthesis) aim at designing molecules with well-defined shape (e.g. bis-peptides).
  • More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation.
  • Atomic force microscope tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called dip-pen nanolithography. This technique fits into the larger subfield of nanolithography.
  • Molecular-beam epitaxy allows for bottom-up assemblies of materials, most notably semiconductor materials commonly used in chip and computing applications, stacks, gating, and nanowire lasers.

Top-down approaches

These seek to create smaller devices by using larger ones to direct their assembly.

Functional approaches

Functional approaches seek to develop useful components without regard to how they might be assembled.

Biomimetic approaches

Speculative

These subfields seek to anticipate what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry could progress. These often take a big-picture view, with more emphasis on societal implications than engineering details.

  • Molecular nanotechnology is a proposed approach that involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields, and many of its proposed techniques are beyond current capabilities.
  • Nanorobotics considers self-sufficient machines operating at the nanoscale. There are hopes for applying nanorobots in medicine. Nevertheless, progress on innovative materials and patented methodologies have been demonstrated.
  • Productive nanosystems are "systems of nanosystems" could produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e. atomic) nature of matter and the possibility of exponential growth, this stage could form the basis of another industrial revolution. Mihail Roco proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, progressing from passive nanostructures to active nanodevices to complex nanomachines and ultimately to productive nanosystems.
  • Programmable matter seeks to design materials whose properties can be easily, reversibly and externally controlled though a fusion of information science and materials science.
  • Due to the popularity and media exposure of the term nanotechnology, the words picotechnology and femtotechnology have been coined in analogy to it, although these are used only informally.

Dimensionality in nanomaterials

Nanomaterials can be classified in 0D, 1D, 2D and 3D nanomaterials. Dimensionality plays a major role in determining the characteristic of nanomaterials including physical, chemical, and biological characteristics. With the decrease in dimensionality, an increase in surface-to-volume ratio is observed. This indicates that smaller dimensional nanomaterials have higher surface area compared to 3D nanomaterials. Two dimensional (2D) nanomaterials have been extensively investigated for electronic, biomedical, drug delivery and biosensor applications.

Tools and techniques

Typical AFM setup. A microfabricated cantilever with a sharp tip is deflected by features on a sample surface, much like in a phonograph but on a much smaller scale. A laser beam reflects off the backside of the cantilever into a set of photodetectors, allowing the deflection to be measured and assembled into an image of the surface.

Scanning microscopes

The atomic force microscope (AFM) and the Scanning Tunneling Microscope (STM) are two versions of scanning probes that are used for nano-scale observation. Other types of scanning probe microscopy have much higher resolution, since they are not limited by the wavelengths of sound or light.

The tip of a scanning probe can also be used to manipulate nanostructures (positional assembly). Feature-oriented scanning may be a promising way to implement these nano-scale manipulations via an automatic algorithm. However, this is still a slow process because of low velocity of the microscope.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are made. Scanning probe microscopy is an important technique both for characterization and synthesis. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques.

Lithography

Various techniques of lithography, such as optical lithography, X-ray lithography, dip pen lithography, electron beam lithography or nanoimprint lithography offer top-down fabrication techniques where a bulk material is reduced to a nano-scale pattern.

Another group of nano-technological techniques include those used for fabrication of nanotubes and nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers.

Bottom-up

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly and positional assembly. Dual-polarization interferometry is one tool suitable for characterization of self-assembled thin films. Another variation of the bottom-up approach is molecular-beam epitaxy or MBE. Researchers at Bell Telephone Laboratories including John R. Arthur. Alfred Y. Cho, and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE lays down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of spintronics.

Therapeutic products based on responsive nanomaterials, such as the highly deformable, stress-sensitive Transfersome vesicles, are approved for human use in some countries.

Applications

One of the major applications of nanotechnology is in the area of nanoelectronics with MOSFET's being made of small nanowires ≈10 nm in length. Here is a simulation of such a nanowire.
Nanostructures provide this surface with superhydrophobicity, which lets water droplets roll down the inclined plane.
Nanowire lasers for ultrafast transmission of information in light pulses
This section needs to be updated. Please help update this article to reflect recent events or newly available information. (May 2024)
Main article: List of nanotechnology applications

As of August 21, 2008, the Project on Emerging Nanotechnologies estimated that over 800 manufacturer-identified nanotech products were publicly available, with new ones hitting the market at a pace of 3–4 per week. Most applications are "first generation" passive nanomaterials that includes titanium dioxide in sunscreen, cosmetics, surface coatings, and some food products; Carbon allotropes used to produce gecko tape; silver in food packaging, clothing, disinfectants, and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst.

In the electric car industry, single wall carbon nanotubes (SWCNTs) address key lithium-ion battery challenges, including energy density, charge rate, service life, and cost. SWCNTs connect electrode particles during charge/discharge process, preventing battery premature degradation. Their exceptional ability to wrap active material particles enhanced electrical conductivity and physical properties, setting them apart multi-walled carbon nanotubes and carbon black.

Further applications allow tennis balls to last longer, golf balls to fly straighter, and bowling balls to become more durable. Trousers and socks have been infused with nanotechnology to last longer and lower temperature in the summer. Bandages are infused with silver nanoparticles to heal cuts faster. Video game consoles and personal computers may become cheaper, faster, and contain more memory thanks to nanotechnology. Also, to build structures for on chip computing with light, for example on chip optical quantum information processing, and picosecond transmission of information.

Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the doctors' offices and at homes. Cars use nanomaterials in such ways that car parts require fewer metals during manufacturing and less fuel to operate in the future.

Nanoencapsulation involves the enclosure of active substances within carriers. Typically, these carriers offer advantages, such as enhanced bioavailability, controlled release, targeted delivery, and protection of the encapsulated substances. In the medical field, nanoencapsulation plays a significant role in drug delivery. It facilitates more efficient drug administration, reduces side effects, and increases treatment effectiveness. Nanoencapsulation is particularly useful for improving the bioavailability of poorly water-soluble drugs, enabling controlled and sustained drug release, and supporting the development of targeted therapies. These features collectively contribute to advancements in medical treatments and patient care.

Nanotechnology may play role in tissue engineering. When designing scaffolds, researchers attempt to mimic the nanoscale features of a cell's microenvironment to direct its differentiation down a suitable lineage. For example, when creating scaffolds to support bone growth, researchers may mimic osteoclast resorption pits.

Researchers used DNA origami-based nanobots capable of carrying out logic functions to target drug delivery in cockroaches.

A nano bible (a .5mm2 silicon chip) was created by the Technion in order to increase youth interest in nanotechnology.

Implications

Main article: Implications of nanotechnology

One concern is the effect that industrial-scale manufacturing and use of nanomaterials will have on human health and the environment, as suggested by nanotoxicology research. For these reasons, some groups advocate that nanotechnology be regulated. However, regulation might stifle scientific research and the development of beneficial innovations. Public health research agencies, such as the National Institute for Occupational Safety and Health research potential health effects stemming from exposures to nanoparticles.

Nanoparticle products may have unintended consequences. Researchers have discovered that bacteriostatic silver nanoparticles used in socks to reduce foot odor are released in the wash. These particles are then flushed into the wastewater stream and may destroy bacteria that are critical components of natural ecosystems, farms, and waste treatment processes.

Public deliberations on risk perception in the US and UK carried out by the Center for Nanotechnology in Society found that participants were more positive about nanotechnologies for energy applications than for health applications, with health applications raising moral and ethical dilemmas such as cost and availability.

Experts, including director of the Woodrow Wilson Center's Project on Emerging Nanotechnologies David Rejeski, testified that commercialization depends on adequate oversight, risk research strategy, and public engagement. As of 206 Berkeley, California was the only US city to regulate nanotechnology.

Health and environmental concerns

A video on the health and safety implications of nanotechnology
Main articles: Health and safety hazards of nanomaterials and Pollution from nanomaterials

Inhaling airborne nanoparticles and nanofibers may contribute to pulmonary diseases, e.g. fibrosis. Researchers found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response and that nanoparticles induce skin aging through oxidative stress in hairless mice.

A two-year study at UCLA's School of Public Health found lab mice consuming nano-titanium dioxide showed DNA and chromosome damage to a degree "linked to all the big killers of man, namely cancer, heart disease, neurological disease and aging".

A Nature Nanotechnology study suggested that some forms of carbon nanotubes could be as harmful as asbestos if inhaled in sufficient quantities. Anthony Seaton of the Institute of Occupational Medicine in Edinburgh, Scotland, who contributed to the article on carbon nanotubes said "We know that some of them probably have the potential to cause mesothelioma. So those sorts of materials need to be handled very carefully." In the absence of specific regulation forthcoming from governments, Paull and Lyons (2008) have called for an exclusion of engineered nanoparticles in food. A newspaper article reports that workers in a paint factory developed serious lung disease and nanoparticles were found in their lungs.

Regulation

Main article: Regulation of nanotechnology

Calls for tighter regulation of nanotechnology have accompanied a debate related to human health and safety risks. Some regulatory agencies cover some nanotechnology products and processes – by "bolting on" nanotechnology to existing regulations – leaving clear gaps. Davies proposed a road map describing steps to deal with these shortcomings.

Andrew Maynard, chief science advisor to the Woodrow Wilson Center's Project on Emerging Nanotechnologies, reported insufficient funding for human health and safety research, and as a result inadequate understanding of human health and safety risks. Some academics called for stricter application of the precautionary principle, slowing marketing approval, enhanced labelling and additional safety data.

A Royal Society report identified a risk of nanoparticles or nanotubes being released during disposal, destruction and recycling, and recommended that "manufacturers of products that fall under extended producer responsibility regimes such as end-of-life regulations publish procedures outlining how these materials will be managed to minimize possible human and environmental exposure".

See also

Main article: Outline of nanotechnology

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