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Nanotechnology
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Nanotechnology (sometimes shortened
to "nanotech") is the manipulation of matter on an atomic and molecular scale. Generally, nanotechnology works
with materials, devices, and other structures with at least one dimension sized
from 1 to 100 nanometres. Quantum mechanical effects are important at thisquantum-realm scale. With a variety of potential
applications, nanotechnology is a key technology for the future and governments
have invested billions of dollars in its research. Through its National
Nanotechnology Initiative, the USA has invested 3.7 billion dollars. The
European Union has invested 1.2 billion and Japan 750 million dollars.[1]
Nanotechnology is very diverse, ranging from
extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the
atomic scale. Nanotechnology entails the application of fields of science as diverse
as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication,
etc.
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 medicine, electronics, biomaterials and energy production. On the other hand, nanotechnology raises many of
the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials,[2] and their potential effects on global
economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among
advocacy groups and governments on whether special regulation of nanotechnology is warranted.
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Contents
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Buckminsterfullerene
C60, also known as the buckyball, is a
representative member of thecarbon structures known asfullerenes. Members of the
fullerene family are a major subject of research falling under the
nanotechnology umbrella.
Although nanotechnology is a relatively recent
development in scientific research, the development of its central concepts
happened over a longer period of time. The emergence of nanotechnology in the
1980s was caused by the convergence of experimental advances such as the
invention of the scanning tunneling microscope in 1981 and the discovery of fullerenes in 1985, with the elucidation
and popularization of a conceptual framework for the goals of nanotechnology
beginning with the 1986 publication of the book Engines of Creation.
The scanning tunneling microscope, an instrument
for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory, for which they
received the Nobel Prize in Physics in 1986.[3][4] Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl, who together won
the 1996 Nobel Prize in Chemistry.[5][6]
Around the same time, K. Eric Drexler developed and popularized the concept
of nanotechnology and founded the field of molecular nanotechnology. In 1979, Drexler
encountered Richard Feynman's 1959 talk There's Plenty of
Room at the Bottom. The term "nano-technology" had been coined by Norio Taniguchi in 1974, and Drexler unknowingly used a version of the term 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. He also first published the term "grey goo" to describe what might happen if a hypothetical self-replicating
molecular nanotechnology went out of control. Drexler's vision of
nanotechnology is often called "Molecular Nanotechnology" (MNT) or
"molecular manufacturing," and Drexler at one point proposed the term
"zettatech" which never became popular.
In the early 2000s, the field was subject to
growing public awareness and controversy, with prominent debates about both its
potential implications, exemplified by the Royal Society's report on nanotechnology,[7] as well as the feasibility of the
applications envisioned by advocates of molecular nanotechnology, which
culminated in the public debate between Eric Drexler and Richard Smalley in
2001 and 2003.[8] Governments moved to promote and fund research into nanotechnology with programs such as the National
Nanotechnology Initiative.
The early 2000s also saw the beginnings of
commercial applications of nanotechnology, although these were limited to bulk
applications of nanomaterials, such
as the Silver Nano platform for using silver nanoparticles as an antibacterial agent, nanoparticle-based
transparent sunscreens, and carbon nanotubes for stain-resistant textiles.[9][10]
Nanotechnology is the engineering of functional
systems at the molecular scale. This covers both current work and concepts that
are more advanced. In its original sense, nanotechnology refers to the
projected ability to construct items from the bottom up, using techniques and tools
being developed today to make complete, high performance products.
One nanometer (nm) is one billionth, or 10−9,
of a meter. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12–0.15 nm, and a DNA double-helix has a diameter around
2 nm. On the other hand, the smallest cellular life-forms, the bacteria of the genus Mycoplasma, are
around 200 nm in length. By convention, nanotechnology is taken as the
scale range 1 to 100 nm following the
definition used by the National Nanotechnology Initiative in the US. The lower
limit is set by the size of atoms (hydrogen has the smallest atoms, which are
approximately a quarter of a nm diameter) since nanotechnology must build its
devices from atoms and molecules. The upper limit is more or less arbitrary but
is around the size that phenomena not observed in larger structures start to
become apparent and can be made use of in the nano device.[11] These new phenomena make nanotechnology
distinct from devices which are merely miniaturised versions of an equivalent macroscopic device; such devices are on a larger scale and come under the
description of microtechnology.[12]
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.[13] 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.[13]
Two main approaches are used in nanotechnology. In
the "bottom-up" approach, materials and devices are built from
molecular components which assemble themselves chemically by principles of molecular recognition. In the
"top-down" approach, nano-objects are constructed from larger
entities without atomic-level control.[14]
Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved during the last few
decades to provide a basic scientific foundation of nanotechnology.
Image of reconstruction on a cleanGold(100) surface, as visualized usingscanning tunneling microscopy. The positions of
the individual atoms composing the surface are visible.
Several phenomena become pronounced as the size of
the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “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. 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 biomaterials.
Materials reduced to the nanoscale can show
different properties compared to what they exhibit on a macroscale, enabling
unique applications. For instance, opaque substances can become transparent
(copper); stable materials can turn combustible (aluminum); insoluble materials
may become soluble (gold). A material such as gold, which is chemically inert
at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination
with nanotechnology stems from these quantum and surface phenomena that matter
exhibits at the nanoscale.[15]
Modern 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 polymers. This ability raises the question of extending this kind of control to
the next-larger level, seeking methods to assemble these single molecules into supramolecular assemblies consisting of many molecules arranged in a well defined manner.
These approaches utilize the concepts of molecular
self-assembly and/or supramolecular chemistry to automatically arrange themselves into some useful conformation
through a bottom-upapproach. 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 intermolecular forces. The Watson–Crick basepairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate, or the specific 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, 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, sometimes called
molecular manufacturing, describes engineered nanosystems (nanoscale machines)
operating on the molecular scale. Molecular nanotechnology is especially
associated with the molecular assembler, a machine that can
produce a desired structure or device atom-by-atom using the principles of mechanosynthesis.
Manufacturing in the context of productive nanosystems is not related to, 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 earlier usage by Norio Taniguchi) it referred to a future manufacturing technology
based on 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, stochastically optimised 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[16] 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.[17] The physics and engineering performance
of exemplar designs were analyzed in Drexler's book Nanosystems.
In general it is very difficult to assemble devices
on the atomic scale, as all one has to position atoms on other atoms of
comparable size and stickiness. Another view, put forth by Carlo Montemagno,[18] is that future nanosystems will be
hybrids of silicon technology and biological molecular machines. Yet another
view, put forward by the late Richard Smalley, is that mechanosynthesis is
impossible due to the difficulties in mechanically manipulating individual
molecules.
This led to an exchange of letters in the ACS publication Chemical &
Engineering News in 2003.[19] Though biology clearly demonstrates
that molecular machine systems are possible, non-biological molecular machines
are today only in their infancy. Leaders in research on non-biological
molecular machines are Dr. Alex Zettl and his colleagues at Lawrence Berkeley
Laboratories and UC Berkeley. They have constructed at least three distinct
molecular devices whose motion is controlled from the desktop with changing
voltage: a nanotube nanomotor, a
molecular actuator,[20] and a nanoelectromechanical relaxation
oscillator.[21] See nanotube
nanomotor for more examples.
An experiment indicating that positional molecular
assembly is possible was performed by Ho and Lee at 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.
This DNA tetrahedron[22] is an artificiallydesigned nanostructure of the type made in the field of DNA nanotechnology. Each edge of the
tetrahedron is a 20 base pair DNAdouble helix, and each vertex is
a three-arm junction.
This device transfers
energy from nano-thin layers of quantum wells to nanocrystalsabove
them, causing the nanocrystals to emit visible light.[23]
The nanomaterials field includes subfields which
develop or study materials having unique properties arising from their
nanoscale dimensions.[24]
·
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.
·
Nanoscale materials are sometimes used in solar cells which combats the cost of traditional Silicon solar cells.
·
Development of applications incorporating semiconductor nanoparticles to be used in the next generation of products, such as display
technology, lighting, solar cells and biological imaging; see quantum dots.
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 nucleic acids.
·
Approaches from the field of "classical" chemical synthesis (inorganic and organic synthesis) also aim at designing molecules with well-defined
shape (e.g. bis-peptides[25]).
·
More generally, molecular self-assembly seeks to use concepts of
supramolecular chemistry, and molecular recognition in particular, to cause
single-molecule components to automatically arrange themselves into some useful
conformation.
·
Atomic force microscope tips can be used as a nanoscale "write head" to deposit a
chemical upon a surface in a desired pattern in a process called dip pen nanolithography. This technique fits
into the larger subfield of nanolithography.
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 microprocessors are now capable of creating features
smaller than 100 nm, falling under the definition of nanotechnology. Giant magnetoresistance-based hard drives
already on the market fit this description,[26] 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.[27]
·
Solid-state techniques can also be used to create devices known as nanoelectromechanical systems or NEMS, which are related tomicroelectromechanical systems or MEMS.
·
Focused ion beams can directly remove material, or even
deposit material when suitable pre-cursor gasses are applied at the same time.
For example, this technique is used routinely to create sub-100 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.
These seek to develop components of a desired
functionality without regard to how they might be assembled.
·
Molecular scale electronics seeks to develop molecules with useful electronic properties. These
could then be used as single-molecule components in a nanoelectronic device.[28] For an example see rotaxane.
·
Synthetic chemical methods can also be used to create synthetic molecular motors, such as in a
so-called nanocar.
·
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 biomolecules for applications in nanotechnology, including use of viruses and lipid
assemblies. [29][30]Nanocellulose is a potential bulk-scale application.
These subfields seek to 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.
·
Nanorobotics centers on self-sufficient machines of
some functionality operating at the nanoscale. There are hopes for applying
nanorobots in medicine,[31][32][33] but it may not be easy to do such a
thing because of several drawbacks of such devices.[34] 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.[35][36]
·
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 USA's National Nanotechnology Initiative, has proposed
four states of nanotechnology that seem to parallel the technical progress of
the Industrial Revolution, progressing from passive nanostructures to active
nanodevices to complex nanomachines and ultimately to productive nanosystems.[37]
·
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 only used rarely
and informally.
Typical AFM setup. A
microfabricated cantilever with a sharp tip is deflected by
features on a sample surface, much like in a phonograph but on a much smaller scale. Alaser 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 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 scanning probe microscopy. Although
conceptually similar tothe scanning confocal
microscope developed by Marvin Minsky in 1961 and the 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). Feature-oriented scanning methodology suggested by Rostislav Lapshin appears to be a promising way
to implement these nanomanipulations in automatic mode.[38][39] 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 ornanoimprint 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.
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.[38][39] 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, 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.
However, new therapeutic products, based on
responsive nanomaterials, such as the ultradeformable, stress-sensitive Transfersome vesicles, are under development and already approved for human use in
some countries.[citation needed]
One of the major
applications of nanotechnology is in the area of nanoelectronics with MOSFET's being made of small nanowires ~10 nm in length. Here is a simulation of such a nanowire.
Nanostructures
provide this surface withsuperhydrophobicity, which lets water droplets roll down the inclined plane.
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.[10] The project lists all of the products
in a publicly accessible online database. Most applications are limited to the
use of "first generation" passive nanomaterials which includes
titanium dioxide in sunscreen, cosmetics, surface coatings,[40] 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.[9]
Further applications allow tennis balls to last longer, golf balls to fly straighter, and even bowling balls 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.[41]Cars are being manufactured with nanomaterials so they may need fewer metals and less fuel to operate in the future.[42] Video game consoles and personal computers may become cheaper, faster, and contain
more memory thanks to nanotechnology.[43] Nanotechnology may have the ability to
make existing medical applications cheaper and easier to use in places like the general practitioner's office and at
home.[44]
The National Science Foundation (a major distributor for nanotechnology research in the United States)
funded researcher David Berube to study the field of nanotechnology. His
findings are published in the monograph Nano-Hype: The Truth Behind the
Nanotechnology Buzz. This study concludes that much of what is sold as
“nanotechnology” is in fact a recasting of straightforward materials science,
which is leading to a “nanotech industry built solely on selling nanotubes,
nanowires, and the like” which will “end up with a few suppliers selling low
margin products in huge volumes." Further applications which require
actual manipulation or arrangement of nanoscale components await further
research. Though technologies branded with the term 'nano' are sometimes little
related to and fall far short of the most ambitious and transformative
technological goals of the sort in molecular manufacturing proposals, the term
still connotes such ideas. According to Berube, there may be a danger that a
"nano bubble" will form, or is forming already, from the use of the
term by scientists and entrepreneurs to garner funding, regardless of interest
in the transformative possibilities of more ambitious and far-sighted work.[45]
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 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 National Institute for Occupational Safety and Health are actively conducting research on potential health effects stemming
from exposures to nanoparticles.[46][47]
Some nanoparticle products may have unintended consequences. Researchers have
discovered that bacteriostatic silver nanoparticles used in socks to reduce foot odor are being
released in the wash.[48] 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.[49]
Public deliberations on risk perception in the US and UK carried out by the Center for Nanotechnology in Society
found that participants were more positive about nanotechnologies for energy
applications than for health applications, with health applications raising
moral and ethical dilemmas such as cost and availability.[50]
Experts, including director of the Woodrow Wilson
Center's Project on Emerging Nanotechnologies David Rejeski, have testified[51] 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;[52] Cambridge, Massachusetts in 2008 considered enacting a similar law,[53] but ultimately rejected it.[54] Relevant for both research on and
application of nanotechnologies, the insurability of nanotechnology is contested.[55] Without state regulation of nanotechnology, the availability of
private insurance for potential damages is seen as necessary to ensure that
burdens are not socialised implicitly.
Main articles: Health implications
of nanotechnology and Environmental
implications of nanotechnology
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[56] and that nanoparticles induce skin
aging through oxidative stress in hairless mice.[57][58]
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".[59]
A major study published more recently in Nature Nanotechnology suggests some forms of carbon nanotubes – a poster child for the
“nanotechnology revolution” – could be as harmful asasbestos if inhaled in sufficient quantities.
Anthony Seaton of the Institute of Occupational Medicine in Edinburgh,
Scotland, who contributed to the article on carbon nanotubes said "We know that some of them
probably have the potential to cause mesothelioma. So those sorts of materials
need to be handled very carefully."[60] In the absence of specific regulation
forthcoming from governments, Paull and Lyons (2008) have called for an
exclusion of engineered nanoparticles in food.[61] A newspaper article reports that
workers in a paint factory developed serious lung disease and nanoparticles
were found in their lungs.[62]
Extremely small fibers, so called nanofibers, can
be as harmful for the lungs as asbestos is. This scientists warn for in the
publication "Toxicology Sciences" after experiments with mice.
Nanofibers are used in several areas and in different products, in everything from
aircraft wings to tennis rackets. In experiments the scientists have seen how
mice breathed nanofibers of silver. Fibers larger than 5 micrometer were capsuled in the lungs where they caused
inflammations[63][64] (a precursor for cancer[65] like mesothelioma).[63]
Calls for tighter regulation of nanotechnology have
occurred alongside a growing debate related to the human health and safety
risks of nanotechnology.[66] 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.[67] Davies (2008) has proposed a regulatory
road map describing steps to deal with these shortcomings.[68]
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 bovine spongiform
encephalopathy ("mad cow" disease), thalidomide, genetically
modified food,[69] nuclear energy, reproductive
technologies, biotechnology, and asbestosis. Dr. Andrew Maynard, chief science advisor to the Woodrow Wilson
Center’s Project on Emerging Nanotechnologies, concludes that there is
insufficient funding for human health and safety research, and as a result
there is currently limited understanding of the human health and safety risks
associated with nanotechnology.[70] As a result, some academics have called
for stricter application of the precautionary principle, with delayed
marketing approval, enhanced labelling and additional safety data development
requirements in relation to certain forms of nanotechnology.[71]
The Royal Society report[7] identified a risk of nanoparticles or
nanotubes being released during disposal, destruction and recycling, and
recommended that “manufacturers of products that fall under extended producer
responsibility regimes such as end-of-life regulations publish procedures
outlining how these materials will be managed to minimize possible human and
environmental exposure” (p. xiii). Reflecting the challenges for ensuring
responsible life cycle regulation, the Institute for Food and Agricultural
Standards has proposed that standards for
nanotechnology research and development should be integrated across consumer,
worker and environmental standards. They also propose that NGOs and other citizen groups play a meaningful role in the development of
these standards.
The Center for Nanotechnology in Society has found
that people respond differently to nanotechnologies based upon 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.[50]
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