View source for Engineering:Nanotechnology

{{short description|Field of science involving control of matter on atomic and (supra)molecular scales}}
{{for multi|the materials science journal|Nanotechnology (journal)|other uses of "Nanotech"|Nanotech (disambiguation)}}
[[File:Fullerene Nanogears - GPN-2000-001535.jpg|thumb|300px|Fullerene nanogears]]

{{Nanotechnology}}
'''Nanotechnology''' was defined by the [[Organization:National Nanotechnology Initiative|National Nanotechnology Initiative]] as 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|surface area]] and [[Physics:Quantum mechanical|quantum mechanical]] effects become important in describing properties of matter. The definition of nanotechnology is inclusive of all types of research and technologies that deal with these special properties. 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.<ref name="Engines1">{{cite book|last=Drexler|first=K. Eric|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=9780385199735}}</ref> An earlier description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as [[Engineering:Molecular nanotechnology|molecular nanotechnology]].<ref name="Nanotsystems">{{cite book|last=Drexler|first=K. Eric|title=Nanosystems: Molecular Machinery, Manufacturing, and Computation|url=https://books.google.com/books?id=F6BRAAAAMAAJ|oclc=26503231|year=1992|publisher=John Wiley & Sons|location=New York|isbn=9780471575474}}</ref>

Nanotechnology as defined by size is naturally broad, including fields of science as diverse as [[Physics:Surface science|surface science]], [[Chemistry:Organic chemistry|organic chemistry]], [[Biology:Molecular biology|molecular biology]], semiconductor physics, [[Engineering:Energy storage|energy storage]],<ref>{{cite journal|last1=Hubler|first1=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}}</ref><ref>{{cite journal|last1=Shinn|first1=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> [[Engineering:Engineering|engineering]],<ref>Elishakoff,I., D. Pentaras, K. Dujat, C. Versaci, G. Muscolino, J. Storch, S. Bucas, N. Challamel, T. Natsuki, Y.Y. Zhang, C.M. Wang and G. Ghyselinck, Carbon Nanotubes and Nano Sensors: Vibrations, Buckling, and Ballistic Impact, ISTE-Wiley, London, 2012, XIII+pp.421; {{ISBN|978-1-84821-345-6}}.</ref> [[Physics:Microfabrication|microfabrication]],<ref>{{cite journal|last1=Lyon|first1=David|last2=et.|first2=al.|s2cid=709782|title=Gap size dependence of the dielectric strength in nano vacuum gaps|journal=[[Physics:IEEE Transactions on Dielectrics and Electrical Insulation|IEEE Transactions on Dielectrics and Electrical Insulation]]|date=2013|doi=10.1109/TDEI.2013.6571470|volume=20|issue=4|pages=1467–1471}}</ref> and [[Physics:Molecular engineering|molecular engineering]].<ref>{{cite journal|last=Saini|first=Rajiv|author2=Saini, Santosh|author3=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 |doi-access=free }}</ref> The associated research and applications are equally diverse, ranging from extensions of conventional [[Physics:Semiconductor device|device physics]] to completely new approaches based upon [[Chemistry:Molecular self-assembly|molecular self-assembly]],<ref>{{cite journal|last1=Belkin|first1=A.|last2=et.|first2=al.|title=Self-Assembled Wiggling Nano-Structures and the Principle of Maximum Entropy Production|journal=Sci. Rep.|date=2015|doi=10.1038/srep08323|pmid=25662746|pmc=4321171|bibcode=2015NatSR...5E8323B|volume=5|pages=8323}}</ref> from developing new materials with dimensions on the nanoscale to [[Engineering:Molecular nanotechnology|direct control of matter on the atomic scale]].

Scientists currently debate the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in nanomedicine, [[Engineering:Nanoelectronics|nanoelectronics]], [[Chemistry:Biomaterial|biomaterial]]s energy production, and consumer products. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the [[Chemistry:Nanotoxicology|toxicity]] and environmental impact of nanomaterials,<ref>{{Cite journal 
|last1=Buzeafirst1 |first1=C. 
|last2=Pachecofirst2 |first2=I. I. 
|last3=Robbiefirst3 |first3=K. 
|s2cid=35457219 
|doi=10.1116/1.2815690 
|title=Nanomaterials and nanoparticles: Sources and toxicity 
|journal=Biointerphases 
|volume=2 
|issue=4 
|pages=MR17–MR71 
|year=2007 
|pmid=20419892
|arxiv=0801.3280 
}}</ref> and their potential effects on global economics, as well as speculation about various [[Grey goo|doomsday scenarios]]. These concerns have led to a debate among advocacy groups and governments on whether special [[Engineering:Regulation of nanotechnology|regulation of nanotechnology]] is warranted.

==Origins==
{{Main|Engineering:History of nanotechnology}}
The concepts that seeded nanotechnology were first discussed in 1959 by physicist [[Biography:Richard Feynman|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.

[[File:Comparison of nanomaterials sizes.jpg|thumb|upright=1.8|right|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, [[Biography:K. Eric Drexler|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" 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 The Foresight Institute (with which he is no longer affiliated) to help increase public awareness and understanding of nanotechnology concepts and implications.

The 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. In the 1980s, two major breakthroughs sparked the growth of nanotechnology in the modern era. First, the invention of the [[Engineering:Scanning tunneling microscope|scanning tunneling microscope]] in 1981 which enabled visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope's developers [[Biography:Gerd Binnig|Gerd Binnig]] and [[Biography:Heinrich Rohrer|Heinrich Rohrer]] at IBM Zurich Research Laboratory received a Nobel Prize in Physics 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|issue=4|year=1986|pages=355–69}}</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, Quate and Gerber also invented the analogous [[Physics:Atomic force microscope|atomic force microscope]] that year.

[[File:C60 Molecule.svg|thumb|upright=0.8|left|Buckminsterfullerene C<sub>60</sub>, 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 were discovered in 1985 by [[Biography:Harry Kroto|Harry Kroto]], [[Biography:Richard Smalley|Richard Smalley]], and [[Biography:Robert Curl|Robert Curl]], who together won the 1996 Nobel Prize in Chemistry.<ref>{{Cite journal|doi=10.1038/318162a0|title=C<sub>60</sub>: Buckminsterfullerene|journal=Nature|volume=318|issue=6042|pages=162–163|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.|s2cid=4314237|bibcode=1985Natur.318..162K}}</ref><ref>{{Cite journal|last1=Adams|first1=W. W.|last2=Baughman|first2=R. H.|doi=10.1126/science.1122120|title=RETROSPECTIVE: Richard E. Smalley (1943-2005)|journal=Science|volume=310|issue=5756|page=1916|year=2005|pmid=16373566|doi-access=free}}</ref> C<sub>60</sub> was not initially described as nanotechnology; the term was used regarding subsequent work with related [[Physics:Carbon nanotube|carbon nanotube]]s (sometimes called [[Physics:Graphene|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 [[Company:NEC|NEC]] 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|first1=Marc|last1=Monthioux|journal=Carbon|volume=44|year=2006|url=http://www.cemes.fr/fichpdf/GuestEditorial.pdf|pages=1621–1623|last2=Kuznetsov|first2=V.|issue=9}}</ref> 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.<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|access-date=13 May 2011|url-status=dead|archive-url=https://web.archive.org/web/20110526060835/http://www.nanotec.org.uk/finalReport.htm|archive-date=26 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|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 [[Physics:Nanomaterials|nanomaterials]] and do not involve atomic control of matter. Some examples include the [[Physics:Silver Nano|Silver Nano]] platform for using silver nanoparticles as an antibacterial agent, [[Physics:Nanoparticle|nanoparticle]]-based transparent sunscreens, [[Chemistry:Carbon fibers|carbon fiber]] strengthening using silica 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=American Elements|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 [[Funding of science|fund research]] into nanotechnology, such as in the U.S. with the [[Organization:National Nanotechnology Initiative|National Nanotechnology Initiative]], which formalized a size-based definition of nanotechnology and established funding for research on the nanoscale, and in Europe via the European Framework Programmes for Research and Technological Development.

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|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>  which center on atomically precise manipulation of matter and discuss existing and projected capabilities, goals, and applications.

==Fundamental concepts==
Nanotechnology is the science and 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.

One nanometer (nm) is one billionth, or 10<sup>−9</sup>, of a meter. By comparison, typical carbon–carbon [[Bond length|bond length]]s, or the spacing between these [[Physics:Atom|atom]]s in a [[Physics:Molecule|molecule]], are in the range {{nowrap|0.12–0.15 nm}}, and a [[Biology:DNA|DNA]] double-helix has a diameter around 2&nbsp;nm. On the other hand, the smallest [[Biology:Cell|cellular]] life-forms, the bacteria of the genus ''[[Medicine:Mycoplasma|Mycoplasma]]'', 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 [[Physics:Kinetic diameter|kinetic diameter]]) since nanotechnology must build its devices from atoms and molecules. The upper limit is more or less arbitrary but is around the size below which the phenomena not observed in larger structures start to become apparent and can be made use of in the nano device.<ref>{{cite book|first1=Fritz|last1=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|publisher=John Wiley and Sons|year=2010|isbn=978-1-4051-7545-6 }}</ref> These new phenomena make nanotechnology distinct from devices that are merely miniaturized versions of an equivalent [[Physics:Macroscopic scale|macroscopic]] device; such devices are on a larger scale and come under the description of [[Engineering:Microtechnology|microtechnology]].<ref>{{cite book|first=S. K.|last=Prasad|title=Modern Concepts in Nanotechnology|pages=31–32|publisher=Discovery Publishing House|year=2008|isbn=978-81-8356-296-6 }}</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"/>

Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which [[Biology:Self-assembly|assemble themselves]] chemically by principles of [[Chemistry:Molecular recognition|molecular recognition]].<ref name="ReferenceA">{{cite journal|last1=Kralj|first1=Slavko|last2=Makovec|first2=Darko|title=Magnetic Assembly of Superparamagnetic Iron Oxide Nanoparticle Clusters into Nanochains and Nanobundles|journal=ACS Nano|date=27 October 2015|volume=9|issue=10|pages=9700–9707|doi=10.1021/acsnano.5b02328|pmid=26394039}}</ref> 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|doi-access=free}}</ref>

Areas of physics such as [[Engineering:Nanoelectronics|nanoelectronics]], [[Physics:Nanomechanics|nanomechanics]], [[Physics:Nanophotonics|nanophotonics]] and [[Engineering:Nanoionics|nanoionics]] have evolved during the last few decades to provide a basic scientific foundation of nanotechnology.

===Larger to smaller: a materials perspective===
[[File:Atomic resolution Au100.JPG|right|thumb|Image of [[Physics:Surface reconstruction|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|Physics:Nanomaterials}}

Several phenomena become pronounced as the size of the system decreases. These include [[Physics:Statistical mechanics|statistical mechanical]] effects, as well as [[Physics:Quantum mechanics|quantum mechanical]] effects, for example the "[[Physics:Quantum|quantum]] 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 [[Quantum realm|quantum realm]]. 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 [[Chemistry:Biomaterial|biomaterial]]s.

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 (aluminium); insoluble materials may become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical [[Chemistry:Catalyst|catalyst]] at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.<ref>{{cite journal|last1=Lubick |first1=N.|year=2008|title=Silver socks have cloudy lining|journal=Environ Sci Technol|volume=42|issue=11|page=3910|pmid=18589943|doi=10.1021/es0871199|last2=Betts|first2=Kellyn|bibcode=2008EnST...42.3910L|s2cid=26887347 }}</ref>

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

Modern [[Chemistry:Chemical synthesis|synthetic chemistry]] 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 pharmaceuticals or commercial [[Chemistry:Polymer|polymer]]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 [[Chemistry:Supramolecular assembly|supramolecular assemblies]] consisting of many molecules arranged in a well defined manner.

These approaches utilize the concepts of molecular self-assembly and/or [[Chemistry:Supramolecular chemistry|supramolecular chemistry]] to automatically arrange themselves into some useful conformation through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed so that a specific configuration or arrangement is favored due to non-covalent [[Physics:Intermolecular force|intermolecular force]]s. The Watson–Crick [[Biology:Base pair|basepairing]] rules are a direct result of this, as is the specificity of an [[Biology:Enzyme|enzyme]] being targeted to a single [[Biology:Substrate (biochemistry)|substrate]], or the specific [[Biology:Protein folding|folding of the protein]] 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.

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 [[Biology:Biology|biology]], 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.

===Molecular nanotechnology: a long-term view===
{{Main|Engineering: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 [[Physics:Molecular assembler|molecular assembler]], a machine that can produce a desired structure or device atom-by-atom using the principles of [[Physics:Mechanosynthesis|mechanosynthesis]]. Manufacturing in the context of [[Physics:Productive nanosystems|productive nanosystems]] is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.

When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an [[Engineering:History of nanotechnology|earlier usage]] by Norio Taniguchi) it referred to a future manufacturing technology based on [[Chemistry:Molecular machine|molecular machine]] 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, [[Stochastic|stochastic]]ally optimized [[Chemistry:Molecular machine#Biological|biological machines]] can be produced.

It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using biomimetic principles. However, Drexler and other researchers<ref>{{cite web|last=Phoenix|first=Chris|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, 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|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>{{cite web|url=http://www.cnsi.ucla.edu/institution/personnel?personnel%5fid=105488|title=Carlo Montemagno, Ph.D.|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> 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.

This led to an exchange of letters in the [[Organization:American Chemical Society|ACS]] publication Chemical & Engineering News in 2003.<ref>{{cite journal|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 machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Alex Zettl and his 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> They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube [[Engineering:Nanomotor|nanomotor]], 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|osti=1017464|url-status=dead|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|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|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> See nanotube nanomotor for more examples.

An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at [[Organization:Cornell University|Cornell University]] 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.

==Current research==
[[File:Rotaxane cartoon.jpg|thumb|right|Graphical representation of a [[Chemistry:Rotaxane|rotaxane]], useful as a molecular switch]]
[[File:DNA tetrahedron white.png|thumb|right|This DNA [[Tetrahedron|tetrahedron]]<ref name="Goodman05">{{cite journal|last=Goodman|first=R.P.|author2=Schaap, I.A.T.|author3=Tardin, C.F.|author4=Erben, C.M.|author5=Berry, R.M.|author6=Schmidt, C.F.|author7=Turberfield, A.J.s2cid=13678773|date=9 December 2005|title=Rapid chiral assembly of rigid DNA building blocks for molecular nanofabrication|journal=Science|volume=310|issue=5754|pages=1661–1665|pmid=16339440|doi=10.1126/science.1120367|bibcode=2005Sci...310.1661G |s2cid=13678773 }}</ref> 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.]]
[[File:C60 Buckyball.gif|thumb|upright=0.9|Rotating view of C<sub>60</sub>, one kind of fullerene]]
[[File:Achermann7RED.jpg|thumb|right|This device transfers energy from nano-thin layers of [[Physics:Quantum well|quantum well]]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|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===
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|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
|s2cid=137324362|bibcode=2004JOM....56j..38N}}</ref>
*[[Physics:Interface and colloid science|Interface and colloid science]] has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various nanoparticles and nanorods. Nanomaterials with fast ion transport are related also to nanoionics and nanoelectronics.
*Nanoscale materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor.
*Progress has been made in using these materials for medical applications; see Nanomedicine.
*Nanoscale materials such as [[Physics:Nanopillar|nanopillar]]s are sometimes used in [[Physics:Solar cell|solar cell]]s which combats the cost of traditional [[Chemistry:Silicon|silicon]] solar cells.
*Development of applications incorporating semiconductor [[Physics:Nanoparticle|nanoparticle]]s to be used in the next generation of products, such as display technology, lighting, solar cells and biological imaging; see quantum dots.
*Recent application of [[Physics:Nanomaterials|nanomaterials]] include a range of biomedical applications, such as [[Engineering:Tissue engineering|tissue engineering]], [[Medicine:Drug delivery|drug delivery]], antibacterials and [[Biology:Biosensor|biosensor]]s.<ref>{{cite journal|last1=Cho|first1=Hongsik|last2=Pinkhassik|first2=Eugene|last3=David|first3=Valentin|last4=Stuart|first4=John|last5=Hasty|first5=Karen|title=Detection of early cartilage damage using targeted nanosomes in a post-traumatic osteoarthritis mouse model|journal=Nanomedicine: Nanotechnology, Biology and Medicine|date=31 May 2015|volume=11|issue=4|pages=939–946|doi=10.1016/j.nano.2015.01.011|pmid=25680539}}</ref><ref>{{cite journal|last1=Kerativitayanan|first1=Punyavee|last2=Carrow|first2=James K.|last3=Gaharwar|first3=Akhilesh K.|title=Nanomaterials for Engineering Stem Cell Responses|journal=Advanced Healthcare Materials|date=May 2015|pages=1600–27|doi=10.1002/adhm.201500272|pmid=26010739|volume=4|issue=11|s2cid=21582516}}</ref><ref>{{cite book|editor1-last=Gaharwar|editor1-first=A.K.|editor2=Sant|editor2-first=S.|editor3-last=Hancock|editor3-first=M.J.|editor4-last=Hacking|editor4-first=S.A.|title=Nanomaterials in tissue engineering : fabrication and applications|date=2013|publisher=Woodhead Publishing|location=Oxford|isbn=978-0-85709-596-1}}</ref><ref>{{cite journal|last1=Gaharwar|first1=A.K.|last2=Peppas|first2=N.A.|last3=Khademhosseini|first3=A.|title=Nanocomposite hydrogels for biomedical applications.|journal=Biotechnology and Bioengineering|date=March 2014|volume=111|issue=3|pages=441–53|pmid=24264728|doi=10.1002/bit.25160|pmc=3924876}}</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|doi=10.3390/nano10081466|pmc=7466539|doi-access=free }}</ref>

===Bottom-up approaches===
These seek 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 [[Biology:Nucleic acid|nucleic acid]]s.
*Approaches from the field of "classical" chemical synthesis (Inorganic and [[Chemistry:Organic synthesis|organic synthesis]]) also aim at designing molecules with well-defined shape (e.g. [[Biology:Bis-peptide|bis-peptide]]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|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.
*[[Physics:Atomic force microscope|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 [[Physics:Nanowire lasers|nanowire lasers]].

===Top-down approaches===
These seek to create smaller devices by using larger ones to direct their assembly.
*Many technologies that descended from conventional solid-state silicon methods for fabricating [[Engineering:Microprocessor|microprocessor]]s are now capable of creating features smaller than 100&nbsp;nm, falling under the definition of nanotechnology. [[Physics:Giant magnetoresistance|Giant magnetoresistance]]-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 [[Physics:Atomic layer deposition|atomic layer deposition]] (ALD) techniques. [[Biography:Peter Grünberg|Peter Grünberg]] and [[Biography:Albert Fert|Albert Fert]] 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|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 [[Nanoelectromechanical systems|nanoelectromechanical systems]] or NEMS, which are related to [[Engineering:Microelectromechanical systems|microelectromechanical systems]] or MEMS.
*[[Focused ion beam]]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 [[Engineering:Transmission electron microscopy|Transmission electron microscopy]].
*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===
These seek to develop components of a desired functionality without regard to how they might be assembled.
*Magnetic assembly for the synthesis of anisotropic superparamagnetic materials such as recently presented magnetic nano chains.<ref name="ReferenceA"/>  
*[[Engineering:Molecular scale electronics|Molecular scale electronics]] seeks to develop molecules with useful electronic properties. These could then 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=2528–2540|year=2007|doi=10.1109/TCSI.2007.907864}}</ref> For an example see rotaxane.
*Synthetic chemical methods can also be used to create [[Physics:Synthetic molecular motor|synthetic molecular motor]]s, such as in a so-called [[Chemistry:Nanocar|nanocar]].

===Biomimetic approaches===

* [[Biology:Bionics|Bionics]] or biomimicry seeks to apply biological methods and systems found in nature, to the study and design of engineering systems and modern technology. [[Earth:Biomineralization|Biomineralization]] is one example of the systems studied.
* Bionanotechnology is the use of [[Physics:Biomolecule|biomolecule]]s for applications in nanotechnology, including use of viruses and lipid assemblies.<ref>{{cite journal|last1=Mashaghi|first1=S.|last2=Jadidi|first2=T.|last3=Koenderink|first3=G.|last4=Mashaghi|first4=A.|title=Lipid Nanotechnology|journal=Int. J. Mol. Sci.|volume=2013|issue=14|pages=4242–4282|doi=10.3390/ijms14024242|pmid=23429269|pmc=3588097|year=2013|doi-access=free }}</ref><ref>Hogan, C. Michael (2010) [http://www.eoearth.org/article/Virus?topic=49496 "Virus"] {{webarchive|url=https://web.archive.org/web/20130513135007/http://www.eoearth.org/article/Virus?topic=49496|date=2013-05-13|website=Encyclopedia of Earth, National Council for Science and the Environment|first=S.|last=Draggan|first2=C.|last2=Cleveland}}</ref> [[Physics:Nanocellulose|Nanocellulose]], a nanopolymer often used for bulk-scale applications, is a green material that has gained interests in nanotechnology and [[Chemistry:Green chemistry|green chemistry]] owing to its useful properties such as abundance, high aspect ratio, good mechanical properties, renewability, and [[Chemistry:Biocompatibility|biocompatibility]].<ref>{{Cite journal|last1=Trache|first1=Djalal|last2=Tarchoun|first2=Ahmed Fouzi|last3=Derradji|first3=Mehdi|last4=Hamidon|first4=Tuan Sherwyn|last5=Masruchin|first5=Nanang|last6=Brosse|first6=Nicolas|last7=Hussin|first7=M. Hazwan|date=2020|title=Nanocellulose: From Fundamentals to Advanced Applications|journal=Frontiers in Chemistry|volume=8|page=392 |doi=10.3389/fchem.2020.00392|pmid=32435633 |pmc=7218176 |bibcode=2020FrCh....8..392T |issn=2296-2646|doi-access=free }}</ref>

===Speculative===
These subfields seek to [[Futures studies|anticipate]] 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.
*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.
*[[Physics:Nanorobotics|Nanorobotics]] centers on self-sufficient machines of some functionality 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=Curr Pharm Biotechnol|volume=6|issue=1|pages=17–33|year=2005|pmid=15727553|doi=10.2174/1389201053167248 }}</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|s2cid=33235348 }}</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|doi=10.2174/187221007779814745|title=Medical Nanorobot Architecture Based on Nanobioelectronics|journal=Recent Patents on Nanotechnology|volume=1|issue=1|pages=1–10|year=2007|last1=Cavalcanti|first1=A.|last2=Shirinzadeh|first2=B.|last3=Freitas|first3=R.|last4=Kretly|first4=L.|s2cid=9807497|pmid=19076015}}</ref><ref>{{cite journal|vauthors=Boukallel M, Gauthier M, Dauge M, Piat E, Abadie J|s2cid=1119820|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|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. Mihail Roco, one of the architects of the US'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 nanomachines and ultimately to productive nanosystems.<ref>{{cite web|url=https://www.nsf.gov/crssprgm/nano/reports/mcr_05-0526_intpersp_nano.pdf|title=International Perspective on Government Nanotechnology Funding in 2005|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 }}</ref>
*[[Biology:Programmable matter|Programmable matter]] seeks to design materials whose properties can be easily, reversibly and externally controlled though a fusion of information science and [[Physics:Materials science|materials science]].
*Due to the popularity and media exposure of the term nanotechnology, the words [[Engineering:Picotechnology|picotechnology]] and [[Engineering:Femtotechnology|femtotechnology]] have been coined in analogy to it, although these are only used rarely and informally.

===Dimensionality in nanomaterials===
Nanomaterials can be classified in 0D, 1D, 2D and 3D [[Physics:Nanomaterials|nanomaterials]]. The dimensionality play 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 indicate that smaller dimensional [[Physics:Nanomaterials|nanomaterials]] have higher surface area compared to 3D nanomaterials. Recently, two dimensional (2D) nanomaterials are extensively investigated for [[Engineering:Electronics|electronic]], biomedical, [[Medicine:Drug delivery|drug delivery]] and [[Biology:Biosensor|biosensor]] applications.

==Tools and techniques==
[[File:AFMsetup.jpg|thumb|right|upright=1.35|Typical [[Physics:Atomic force microscope|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.]]

There are several important modern developments. The [[Physics:Atomic force microscope|atomic force microscope]] (AFM) and the Scanning Tunneling Microscope (STM) are two early versions of scanning probes that launched nanotechnology. There are other types of [[Physics:Scanning probe microscopy|scanning probe microscopy]]. Although conceptually similar to the scanning confocal microscope developed by [[Biography:Marvin Minsky|Marvin Minsky]] in 1961 and the [[Engineering:Scanning acoustic microscope|scanning acoustic microscope]] (SAM) developed by Calvin Quate 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 tip of a scanning probe can also be used to manipulate nanostructures (a process called positional assembly). [[Engineering:Feature-oriented scanning|Feature-oriented scanning]] methodology may be a promising way to implement these nanomanipulations in automatic mode.<ref name="feature2004">{{cite journal|author=Lapshin, R. V.|year=2004|title=Feature-oriented scanning methodology for probe microscopy and nanotechnology|journal=Nanotechnology|volume=15|issue=9|pages=1135–1151|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|author=Lapshin, R. V.|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=US|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 scanning velocity of the microscope.

Various techniques of nanolithography such as optical lithography, X-ray lithography, dip pen nanolithography, electron beam lithography or [[Engineering:Nanoimprint lithography|nanoimprint lithography]] were also developed. Lithography is a top-down fabrication technique where a bulk material is reduced in size to nanoscale pattern.

Another group of nanotechnological 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. 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.<ref name="pmid26295171">{{cite journal|last1=Kafshgari|first1=M. H.|last2=Voelcker|first2=N. H.|last3=Harding|first3=F. J.|year=2015|title=Applications of zero-valent silicon nanostructures in biomedicine|journal=Nanomedicine (London)|volume=10 |issue=16 |pages=2553–71doi=10.2217/nnm.15.91pmid=26295171 |doi=10.2217/nnm.15.91 |pmid=26295171 }}</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.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, [[Biology:Self-assembly|self-assembly]] and positional assembly. Dual polarisation interferometry is one tool suitable for characterisation of self assembled thin films. Another variation of the bottom-up approach is molecular beam epitaxy or MBE. Researchers at Bell Telephone Laboratories 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 [[Spintronics|spintronics]].

However, new therapeutic products, based on responsive nanomaterials, such as the ultradeformable, stress-sensitive [[Biology:Transfersome|Transfersome]] vesicles, are under development and already approved for human use in some countries.<ref>{{Cite journal|last1=Rajan|first1=Reshmy|last2=Jose|first2=Shoma|last3=Mukund|first3=V. P. Biju|last4=Vasudevan|first4=Deepa T.|date=2011-01-01|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|doi=10.4103/2231-4040.85524|pmc=3217704|pmid=22171309 |doi-access=free }}</ref>

==Applications==
[[File:Threshold formation nowatermark.gif|thumb|right|upright=1.8|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.]]
[[File:A-simple-and-fast-fabrication-of-a-both-self-cleanable-and-deep-UV-antireflective-quartz-1556-276X-7-430-S1.ogv|thumb|Nanostructures provide this surface with superhydrophobicity, which lets water droplets roll down the inclined plane.]]
[[File:Nanowire laser.png|thumb|Nanowire lasers for ultrafast transmission of information in light pulses]]

As of August 21, 2008, the [[Project on Emerging Nanotechnologies]] 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 "firstgeneration" passive nanomaterials which includes titanium dioxide in sunscreen, cosmetics, surface coatings,<ref>{{cite journal|last1=Kurtoglu|first1=M. E.|last2=Longenbach|first2=T.|last3=Reddington|first3=P.|last4=Gogotsi|first4=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=1101–1108|doi=10.1111/j.1551-2916.2010.04218.x}}</ref> 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.<ref name="americanelements"/>

Further applications allow [[Engineering:Tennis ball|tennis ball]]s to last longer, [[Engineering:Golf ball|golf ball]]s to fly straighter, and even [[Engineering:Bowling ball|bowling ball]]s to become more durable and have a harder surface. Trousers and socks have been infused with nanotechnology so that they will last longer and keep people cool in the summer. Bandages 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|work=nnin.org|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> [[Engineering:Video game console|Video game console]]s and [[Engineering:Personal computer|personal computer]]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|doi=10.1021/acs.nanolett.5b03404|pmid=26618638|volume=16|issue=1|title=Monolithically Integrated High-β Nanowire Lasers on Silicon|year=2015|journal=Nano Letters|pages=152–156|last1=Mayer|first1=B.|last2=Janker|first2=L.|last3=Loitsch|first3=B.|last4=Treu|first4=J.|last5=Kostenbader|first5=T.|last6=Lichtmannecker|first6=S.|last7=Reichert|first7=T.|last8=Morkötter|first8=S.|last9=Kaniber|first9=M.|last10=Abstreiter|first10=G.|last11=Gies|first11=C.|last12=Koblmüller|first12=G.|last13=Finley|first13=J. J.|bibcode=2016NanoL..16..152M }}</ref>

Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the general practitioners' 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 are being manufactured using nanomaterials in such ways that car parts require fewer [[Chemistry:Metal|metal]]s during manufacturing and less fuel 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>

Nanoencapsulation is a technology involving the enclosure of active substances within carriers or particles of nanometer size. Typically, these carriers are nanoparticles that offer various 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 and therapeutic strategies. It facilitates more efficient drug administration, minimizing side effects, and increasing treatment effectiveness by encapsulating drugs within nanoparticles. 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 |last1=Kumari |first1=Avnesh |last2=Singla |first2=Rubbel |last3=Guliani |first3=Anika |last4=Yadav |first4=Sudesh |date=March 2014 |title=Nanoencapsulation for Drug Delivery. |journal=Excli Journal |volume=13 |pages=265–286 |pmid=26417260 |pmc=4464443 }}</ref><ref>{{Cite web |last1=Suganya |first1=V |last2=Anuradha |first2=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>

Scientists are now turning to nanotechnology in an attempt to develop diesel engines with cleaner exhaust fumes. Platinum is currently used as the diesel engine [[Chemistry:Catalysis|catalyst]] in these engines. The catalyst is what cleans the exhaust fume particles. First, a reduction catalyst is employed to take nitrogen atoms from NOx molecules in order to free oxygen. Next the oxidation catalyst oxidizes the hydrocarbons and carbon monoxide to form carbon dioxide and water.{{cn|date=January 2023}} Platinum is used in both the reduction and the oxidation catalysts.<ref>{{cite web|url=http://auto.howstuffworks.com/catalytic-converter2.htm|title=How Catalytic Converters Work|archive-url=https://web.archive.org/web/20141210142147/http://auto.howstuffworks.com/catalytic-converter2.htm|archive-date=2014-12-10|website=HowStuffWorks|date=8 November 2000 }}</ref> Using platinum though, is inefficient in that it is expensive and unsustainable. Danish company InnovationsFonden invested DKK 15 million in a search for new catalyst substitutes using nanotechnology. The goal of the project, launched in the autumn of 2014, is to maximize surface area and minimize the amount of material required. Objects tend to minimize their surface energy; two drops of water, for example, will join to form one drop and decrease surface area. If the catalyst's surface area that is exposed to the exhaust fumes is maximized, efficiency of the catalyst is maximized. The team working on this project aims to create nanoparticles that will not merge. Every time the surface is optimized, material is saved. Thus, creating these nanoparticles will increase the effectiveness of the resulting diesel engine catalyst—in turn leading to cleaner exhaust fumes—and will decrease cost. If successful, the team hopes to reduce platinum use by 25%.<ref>{{cite web|url=http://www.rdmag.com/news/2014/09/nanotechnology-provide-cleaner-diesel-engines|title=Nanotechnology to provide cleaner diesel engines|archive-url=https://web.archive.org/web/20141214133618/http://www.rdmag.com/news/2014/09/nanotechnology-provide-cleaner-diesel-engines|archivedate=2014-12-14|website=RDmag.com|date=September 2014}}</ref>

Nanotechnology also has a prominent role in the fast developing field of Tissue Engineering. When designing scaffolds, researchers attempt to mimic the nanoscale features of a [[Biology:Cell|cell]]'s microenvironment to direct its differentiation down a suitable lineage.<ref>{{Cite journal|doi=10.4137/BTRI.S12331|title=Nanotechnology in the Regeneration of Complex Tissues|journal=Bone and Tissue Regeneration Insights|year=2014|last1=Cassidy|first1=John W.|pmc=4471123|pmid=26097381|volume=5|pages=25–35}}</ref> For example, when creating scaffolds to support the growth of bone, researchers may mimic [[Biology:Osteoclast|osteoclast]] resorption pits.<ref>{{Cite journal|doi=10.1016/j.actbio.2013.11.008|pmid=24252447|pmc=3907683|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|year=2014|last1=Cassidy|first1=J. W.|last2=Roberts|first2=J. N.|last3=Smith|first3=C. A.|last4=Robertson|first4=M.|last5=White|first5=K.|last6=Biggs|first6=M. J.|last7=Oreffo|first7=R. O. C.|last8=Dalby|first8=M. J.|url=http://eprints.soton.ac.uk/367171/|url-status=live|archive-url=https://web.archive.org/web/20170830234634/https://eprints.soton.ac.uk/367171/|archive-date=2017-08-30}}</ref>

Researchers have successfully used DNA origami-based nanobots capable of carrying out logic functions to achieve targeted drug delivery in cockroaches. It is said that the computational power of these nanobots can be scaled up to that of a [[Engineering:Commodore 64|Commodore 64]].<ref>{{Cite journal|doi=10.1038/nnano.2014.58|title=Universal computing by DNA origami robots in a living animal|journal=Nature Nanotechnology|volume=9|issue=5|pages=353–357|year=2014|last1=Amir|first1=Y.|last2=Ben-Ishay|first2=E.|last3=Levner|first3=D.|last4=Ittah|first4=S.|last5=Abu-Horowitz|first5=A.|last6=Bachelet|first6=I.|bibcode=2014NatNa...9..353A|url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:13454727|pmc=4012984|pmid=24705510}}</ref>

==Implications==

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 [[Chemistry:Nanotoxicology|nanotoxicology]] 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. Public health research agencies, such as the [[Organization:National Institute for Occupational Safety and Health|National Institute for Occupational Safety and Health]] are actively conducting research on 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=CDC – Nanotechnology – 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 book|url=https://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|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}}</ref>

Some nanoparticle products may have [[Social:Unintended consequences|unintended consequences]]. Researchers have discovered that bacteriostatic silver nanoparticles used in socks to reduce foot odor are being released in the wash.<ref>{{Cite journal|pmid=18589943|doi=10.1021/es0871199|bibcode=2008EnST...42.3910L|year=2008|last1=Lubick|first1=N|last2=Betts|first2=Kellyn|title=Silver socks have cloudy lining
|journal=Environmental Science & Technology
|volume=42
|issue=11
|page=3910
|s2cid=26887347 }}</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. (1993) ''Advances in Bacterial Paracrystalline Surface Layers''. T. J. Beveridge, S. F. Koval (Eds.). Plenum Press. {{ISBN|978-0-306-44582-8}}. pp. 3–9.</ref>

Public deliberations on [[Risk perception|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.<ref name="harthorn">{{cite web|last=Harthorn|first=Barbara Herr|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>{{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 successful commercialization depends on adequate oversight, risk research strategy, and public engagement. Berkeley, California is currently the only city in the United States to regulate nanotechnology;<ref>{{cite news|last=DelVecchio|first=Rick|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.com}}</ref> In 2008, Cambridge, Massachusetts considered enacting a similar law,<ref>{{cite web|last=Bray|first=Hiawatha|date=2007-01-26|url=http://boston.com/business/technology/articles/2007/01/26/cambridge_considers_nanotech_curbs/|title=Cambridge considers nanotech curbs – City may mimic Berkeley bylaws|archive-url=https://web.archive.org/web/20080511204110/http://www.boston.com/business/technology/articles/2007/01/26/cambridge_considers_nanotech_curbs/|archive-date=2008-05-11|website=boston.com}}</ref> but ultimately rejected it.<ref>{{cite web|url=http://www.nanolawreport.com/Cambridge.pdf|title=Recommendations for a Municipal Health & Safety Policy for Nanomaterials: A Report to the Cambridge City Manager|archive-url=https://web.archive.org/web/20110714153113/http://www.nanolawreport.com/Cambridge.pdf|archive-date=2011-07-14|website=nanolawreport.com|date=July 2008}}</ref>

===Health and environmental concerns===
[[File:NIOSH Nano Research - Engineering Controls for Nanomaterial Production and Handling Processes.webm|thumb|A video on the health and safety implications of nanotechnology]]
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 pulmonary diseases, e.g. [[Medicine:Fibrosis|fibrosis]].<ref>{{Cite journal|pmid=18523535|pmc=2322933|year=2008|last1=Byrne|first1=J. D.|title=The significance of nanoparticles in particle-induced pulmonary fibrosis|journal=McGill Journal of Medicine|volume=11|issue=1|pages=43–50|last2=Baugh|first2=J. A.}}</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>{{cite web|last=Elder|first=Alison|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|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|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=Toxicology Letters}}</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>

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>{{cite web|last=Schneider|first=Andrew|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 [[Engineering:Nature Nanotechnology|Nature Nanotechnology]] study suggests some forms of [[Physics:Carbon nanotube|carbon nanotubes]] – a poster child for the "nanotechnology revolution" – could be as harmful as [[Chemistry:Asbestos|asbestos]] if inhaled in sufficient quantities. Anthony Seaton of the [[Organization:Institute of Occupational Medicine|Institute of Occupational Medicine]] in Edinburgh, Scotland, who contributed to the article on [[Physics:Carbon nanotube|carbon nanotube]]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|last=Weiss|first=Rick|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={{wipe|The Washington Post}} |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|author1=Paull, J.|author2=Lyons, K.|name-list-style=amp|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|first=Rebecca|last=Smith|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 name="">{{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|doi=10.1093/toxsci/kfs171|pmid=22584686|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|year=2012|last1=Schinwald|first1=A.|last2=Murphy|first2=F. A.|last3=Prina-Mello|first3=A.|last4=Poland|first4=C. A.|last5=Byrne|first5=F.|last6=Movia|first6=D.|last7=Glass|first7=J. R.|last8=Dickerson|first8=J. C.|last9=Schultz|first9=D. A.|last10=Jeffree|first10=C. E.|last11=MacNee|first11=W.|last12=Donaldson|first12=K.|doi-access=free}}</ref><ref>{{cite web|url=http://www.scientificamerican.com/article.cfm?id=chronic-inflammation-cancer|title=Is Chronic Inflammation the Key to Unlocking the Mysteries of Cancer?|website=Scientific American }}{{webarchive|url=https://web.archive.org/web/20121104234734/http://www.scientificamerican.com/article.cfm?id=chronic-inflammation-cancer|date=2012-11-04 }} Scientific American. 2008-11-09</ref>

==Regulation==
{{Main|Engineering: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|author=Kevin Rollins (Nems Mems Works, LLC)|work=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> 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|vauthors=Bowman D, 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>{{cite web|last=Davies|first=J. C.|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>

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 [[Medicine:Bovine spongiform encephalopathy|bovine spongiform encephalopathy]] ("mad cow" disease), [[Chemistry:Thalidomide|thalidomide]], genetically modified food,<ref>{{Cite journal|doi=10.1177/0963662505056611|title=Difficulties in evaluating public engagement initiatives: Reflections on an evaluation of the UK GM Nation? Public debate about transgenic crops|journal=Public Understanding of Science|volume=14|issue=4|pages=331–352|year=2005|last1=Rowefirst1=G.|s2cid=144572555|url=http://www.ssoar.info/ssoar/handle/document/22386|type=Submitted manuscript}}</ref> nuclear energy, reproductive technologies, biotechnology, and [[Medicine:Asbestosis|asbestosis]]. 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>{{cite web|last=Maynard|first=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> As a result, some academics have called for stricter application of the [[Precautionary principle|precautionary principle]], with delayed marketing approval, enhanced labelling and additional safety data development requirements in relation to certain forms of nanotechnology.<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|last1=Faunce|first1=T.|last2=Murray|first2=K.|last3=Nasu|first3=H.|last4=Bowman|first4=D.|s2cid=55719697 }}</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).

The Center for Nanotechnology in Society has found that people respond to nanotechnologies differently, depending on application – with participants in public deliberations 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==
{{Main|Engineering:Outline of nanotechnology}}
{{wikt}}
{{div col|colwidth=20em}}
* [[Physics:Carbon nanotube|Carbon nanotube]]
* Electrostatic deflection (molecular physics/nanotechnology)
* [[Engineering:Energy applications of nanotechnology|Energy applications of nanotechnology]]
* [[Engineering:Ethics of nanotechnologies|Ethics of nanotechnologies]]
* [[Physics:Ion implantation-induced nanoparticle formation|Ion implantation-induced nanoparticle formation]]
* Gold nanoparticle
* [[Social:List of emerging technologies|List of emerging technologies]]
* [[Company:List of nanotechnology organizations|List of nanotechnology organizations]]
* [[Physics:List of software for nanostructures modeling|List of software for nanostructures modeling]]
* [[Physics:Magnetic nanochains|Magnetic nanochains]]
* [[Physics:Materiomics|Materiomics]]
* [[Physics:Nano-thermite|Nano-thermite]]
* [[Software:Molecular design software|Molecular design software]]
* [[Chemistry:Molecular mechanics|Molecular mechanics]]
* [[Engineering:Nanobiotechnology|Nanobiotechnology]]
* [[Engineering:Nanoelectromechanical relay|Nanoelectromechanical relay]]
* [[Physics:Nanoengineering|Nanoengineering]]
* [[Chemistry:Nanofluidics|Nanofluidics]]
* [[NanoHUB]]
* [[Nanometrology]]
* [[Biology:Nanoneuronics|Nanoneuronics]]
* [[Physics:Nanoparticle|Nanoparticle]]
* Nanoscale networks
* [[Engineering:Nanotechnology education|Nanotechnology education]]
* Nanotechnology in fiction
* Nanotechnology in water treatment
* Nanoweapons
* [[Organization:National Nanotechnology Initiative|National Nanotechnology Initiative]]
* [[Self-assembly of nanoparticles]]
* Top-down and bottom-up
* [[Translational research]]
* [[Engineering:Wet nanotechnology|Wet nanotechnology]]
{{div col end}}

==References==
{{reflist|30em}}

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