Editing Nanotechnology (section)

==Research==
[[File:Rotaxane cartoon.jpg|thumb|right|Graphical representation of a [[rotaxane]], useful as a [[molecular switch]]]]
[[File:DNA tetrahedron white.png|thumb|right|This DNA [[tetrahedron]]<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 [[Nucleic acid design|designed]] nanostructure of the type made in the field of [[DNA nanotechnology]]. Each edge of the tetrahedron is a 20 base pair DNA [[Nucleic acid double helix|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 [[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 | 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===
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>
*[[Interface and colloid science]] produced many materials that may be useful in nanotechnology, such as carbon nanotubes and other [[fullerenes]], and various nanoparticles and [[nanorod]]s. Nanomaterials with fast ion transport are related to nanoionics and nanoelectronics.
*Nanoscale materials can be used for bulk applications; most commercial applications of nanotechnology are of this flavor.
*Progress has been made in using these materials for [[Nanomedicine|medical applications]], including [[tissue engineering]], [[drug delivery]], [[antibacterials]] and [[biosensor]]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 such as [[nanopillar]]s are used in [[solar cell]]s.
*Applications incorporating semiconductor [[nanoparticle]]s in products such as display technology, lighting, solar cells and biological imaging; see [[quantum dot]]s.

===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 acid]]s.
*Approaches from the field of "classical" chemical synthesis (inorganic and [[organic synthesis]]) aim at designing molecules with well-defined shape (e.g. [[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| 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.
*[[Atomic force microscopy|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.
*Many technologies that descended from conventional [[semiconductor fabrication|solid-state silicon methods]] for fabricating [[microprocessor]]s are capable of creating features smaller than 100&nbsp;nm. [[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 [[atomic layer deposition]] (ALD) techniques. [[Peter Grünberg]] and [[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 be used to create [[nanoelectromechanical systems]] or NEMS, which are related to [[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 [[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===
Functional approaches seek to develop useful components without regard to how they might be assembled.
*Magnetic assembly for the synthesis of [[Anisotropy|anisotropic]] [[superparamagnetic]] materials such as magnetic nano chains.<ref name="ReferenceA"/>
*[[Molecular scale electronics]] 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 [[rotaxane]].
*Synthetic chemical methods can be used to create [[synthetic molecular motor]]s, such as in a so-called [[nanocar]].

===Biomimetic approaches===
* [[Bionics]] or [[biomimicry]] seeks to apply biological methods and systems found in nature to the study and design of engineering systems and modern technology. [[Biomineralization]] is one example of the systems studied.
* [[Bionanotechnology]] is the use of [[biomolecule]]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> [[Nanocellulose]], a nanopolymer often used for bulk-scale applications, has gained interest owing to its useful properties such as abundance, high aspect ratio, good [[mechanical properties]], [[renewability]], and [[biocompatibility]].<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>

===Speculative===
These subfields seek to [[Futures studies|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.<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" 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 [[nanomachine]]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>
*[[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 [[:wikt:physical|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 [[electronics|electronic]], [[biomedical]], [[drug delivery]] and [[biosensor]] applications.