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Nanoscience and nanotechnology: ethical, legal, social and environmental issues


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The present article attempts to understand the debate over nanoscience and nanotechnology regarding
its potential benefits to the society. One view in this debate is that nanoscience and nanotechnology
has a revolutionary potential and will have significant economic benefits, while the other view is
skeptical about its potential in the context of ethical, legal, social and environmental (ELSE) issues
and values such as equity and justice. In some developed countries, discussion on the ELSE issues of
nanoscience and nanotechnology has already begun. Hence, there is a need to take a cue from the
debate in the developed countries and focus our attention on these issues in the Indian context. The
ELSE issues should be addressed right from the beginning of the development of nanoscience and
nanotechnology, so that it is possible to make informed policy decisions.


Initiatives, potential applications and controversies

Nanoscience and nanotechnology is about the precise and
purposeful manipulation of matter at the atomic level.
Burgi and Pradeep4 provide a comprehensive account of
the development of nanotechnology. The modern conceptual
underpinning of nanoscience and nanotechnology
was laid by the physicist Richard Feynman (1959) in his
lecture ‘There is plenty of room at the bottom’5. The
scanning tunnelling microscope (STM), a novel measuring
instrument invented by Gerhard Binnig and Heinrich
Rohrer, who were awarded the Nobel Prize for their invention
in 1986, enabled scientists to ‘see’ matter at the
nanoscale and ‘manipulate’ matter at that level. This is an
example of a technology that played an important role in
opening up a new field of scientific inquiry.


Conclusion
Nanoscience and nanotechnology, like any other knowledge
and associated practices that were developed in the
past, is getting shaped by scientific, technological, economic
and cultural forces. Different sections – enthusiasts and
skeptics – of this new technology are engaged in a debate
about the degree of desirability of this technology from
different value-premises and interpretations of the new
technoscience. In the Western countries research on ELSE
dimensions of nanoscience and nanotechnology has been
recognized as a legitimate field of inquiry. Research on
social, economic, environmental and health effects of nanoscience
and nanotechnology, and risks associated with
this new technology and regulatory norms have been initiated
with adequate funding. In India, similar evaluations
of nanoscience and nanotechnology have not been taken
up yet. The nanoscience and nanotechnology community
in India, except a few members, does not seem to appreciate
the ELSE issues relating to nanotechnology adequately.

Nanoscience and nanotechnology

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Introduction

Nanotechnology, whose prefix "nano" comes from the Greek word "nanos" and represents one-billionth of a unit, utilizes nanoscience, the "science of the small," to manipulate systems at the level of atoms, molecules, and supramolecular structures. Control of matter at the nanoscale already plays an important role in scientific disciplines as diverse as physics, chemistry, materials science, biology, medicine, engineering, and computer simulation.
Nanoscience is the study of phenomena on a nanometer scale. Atoms are a few tenths of a nanometer in diameter and molecules are typically a few nanometers in size. The smallest structures humans have made have dimensions of a few nanometers and the smallest structures we will ever make will have the dimensions of a few nanometers. This is because as soon as a few atoms are placed next to each other, the resulting structure is a few nanometers in size. The smallest transistors, memory elements, light sources, motors, sensors, lasers, and pumps are all just a few nanometers in size.
Nanoscience and nanotechnology affect all areas of life, until recently; they were primarily concerned with electronics, manufacturing, supercomputers, and data storage devices. Recently, nanoscientists have broadened the application of nanotechnology. To produce new kinds of corrosive-protective and wear-resistant coatings for windows, cars, machines, and planes, researchers are working on making existing products more efficient, from more effective sunscreen and hair dyes to a new breed of thin-film lithium-ion batteries. Near-future nanotechnology applications include more efficient fuel and solar cells, the reduction of carbon dioxide emissions in cars, and a new world of sensors in a variety of fields, from bioterrorism to biotechnology.
One of the first people to point out potential benefits of making devices at the nanoscale was Richard Feynman. In a speech he gave in 1959 entitled, There's plenty of room at the bottom, Feynman talked about "the problem of manipulating and controlling things on a small scale." He estimated that it should be possible to reduce the printing on a page by a factor of 25000 and if that were done, all the books ever printed could be copied in a space of about 35 ordinary pages. Feynman also speculated about moving individual atoms around. Here's what he had to say about rearranging atoms.

Advantages of nanoscience

The advantages to nanoscience are widely varied based on the particle size. Generally, nanoscience is the study of things that change their properties when they are brought down to a very small scale. One advantage to all nanoparticles is their surface area to volume ratio. When any kind of shape is shrunk, its volume decreases at a faster rate than its surface area. For example, compare the rate at which a log burns in a fire to the rate in which a log that has been cut into quarters burns in a similar fire, find that the cut log would burn faster. This is because in most chemical reactions, the atoms/molecules lining the surface of the substrate are the ones that are active in the reaction, while those in the center of the particle are latent. Increasing the active molecules to latent molecules ratio is the key part in increasing the efficiency of things such as catalysts (which increase the rate of reaction but are not used in the reaction).

Application of nanoscience

Nanoparticles have a very large surface area for their size or volume. This gives them different properties and uses compared to larger materials which are made from the same substance.
Nanoparticles are usedin sunscreens, sports equipment, drug deliverycoatings and medicine.Future uses include catalysts, computers and building materials.
One of the good example of widely used nano particle is nano silver.Nano silver is the name given to nanoparticles of silver.Only a very thin coating of nano silver needs to be used.The very high surface area of this type of coating
gives a big improvement in the properties of silver that prevent bacterial or fungal growth.Nano silver is used in dressings for injuries caused by burns and wounds caused by surgery.

Nanomaterials

Nanomaterials is a field that takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those that have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer.

Another definition of a nanomaterial:

A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm. In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.
An important aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nanoscale materials, which makes possible new quantum mechanical effects. One example is 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, it becomes pronounced when the nanometer size range is reached. A certain number of physical properties also alter with the change from macroscopic systems. Novel mechanical properties of nanomaterials is a subject of nanomechanics research. Catalytic activities also reveal new behaviour in the interaction with biomaterials.

Nanoparticles

Nanoparticles or nanocrystals made of metals, semiconductors, or oxides are of particular interest for their mechanical, electrical, magnetic, optical, chemical and other properties. Nanoparticles have been used as quantum dots and as chemical catalysts.
Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures. A bulk material should have constant physical properties regardless of its size, but at the nano-scale this is often not the case. Size-dependent properties are observed such as quantum confinement in semiconductor particles, surface plasmon resonance in some metal particles and superparamagnetism in magnetic materials.
Nanoparticles exhibit a number of special properties relative to bulk material. For example, the bending of bulk copper (wire, ribbon, etc.) occurs with movement of copper atoms/clusters at about the 50 nm scale. Copper nanoparticles smaller than 50 nm are considered super hard materials that do not exhibit the same malleability and ductility as bulk copper. The change in properties is not always desirable. Ferroelectric materials smaller than 10 nm can switch their magnetisation direction using room temperature thermal energy, thus making them useless for memory storage. Suspensions of nanoparticles are possible because the interaction of the particle surface with the solvent is strong enough to overcome differences in density, which usually result in a material either sinking or floating in a liquid. Nanoparticles often have unexpected visual properties because they are small enough to confine their electrons and produce quantum effects. For example gold nanoparticles appear deep red to black in solution.

Characterization

The first observations and size measurements of nano-particles were made during the first decade of the 20th century. They are mostly associated with the name of Zsigmondy who made detailed studies of gold sols and other nanomaterials with sizes down to 10 nm and less. He published a book in 1914. He used an ultramicroscope that employs a dark field method for seeing particles with sizes much less than light wavelength.
There are traditional techniques developed during 20th century in Interface and Colloid Science for characterizing nanomaterials. These are widely used for first generation passive nanomaterials specified in the next section.
These methods include several different techniques for characterizing particle size distribution. This characterization is imperative because many materials that are expected to be nano-sized are actually aggregated in solutions. Some of methods are based on light scattering. Other apply ultrasound, such as ultrasound attenuation spectroscopy for testing concentrated nano-dispersions and microemulsions.