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Showing posts with label nanomaterials. Show all posts

Nanochemistry

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Nanochemistry is a branch of nanoscience dealing with synthesis, characterisation and applications of nanomaterials. Various chemical and physical techniques are used to manipulate atoms and molecules ranging in size between 1-100nm. These are used as building blocks to form nanomaterials, nanostructures, nanobots and nanoassemblies. When these are coupled with biological materials such as neurons or electronics or computers exciting new  possibilities and  applications emerge. 

Chemical reactions can be used to assemble atoms in molecular structures and physical techniques are employed to manipulate and position atoms for specific applications. Novel chemical synthesis can be used to make nanoscale structures used for building blocks with the desired shapes, surface area, structure, composition and size. The nanoscale feature endows unique structural and optical properties for use in catalysis, electro-optical devices and nanocarrier systems for drug delivery.There are many naturally occuring nanoassemblies such as liposomes, polypeptide miscelles etc.Nanomaterials exhibit properties that are distinct  to those of bulk materials and have important applications such as sunscreens to block harmful UV light from the sun and catalysts with an unusually large surface area to speed up chemical reactions in industrial production of important compounds and medical products.

One of the most popular nanomaterial is the carbon nanotube.  These have 1/6th  the weight of steel but much stronger.  Other materials may also form nanotubes. They can be excellent insulators or conduct electricity better than copper used in semiconductor devices. TiO2 is commonly used in self cleaning windows and ovens.

Green Nanotechnology

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There is a general perception that nanotechnologies will have a significant impact on developing 'green' and 'clean' technologies with considerable environmental benefits. The best examples are the use of nanotechnology in areas ranging from water treatment to energy breakthroughs and hydrogen applications. As a matter of fact, renewable energy applications probably are the areas where nanotechnology will make its first large-scale commercial breakthroughs.

Researchers agree that the safest possible future for advancing nanotechnology in a sustainable world can be reached by using green chemistry. Green chemistry means designing chemical products and processes in a way that reduces or eliminates hazardous substances from the beginning to end of a chemical product’s life cycle. The practice began in the United States with the passage of the Pollution Prevention Act of 1990, which established a national policy to prevent or reduce pollution at its source whenever feasible. Reducing pollution at the source, according to the act, "is fundamentally different and more desirable" than managing waste and controlling pollution. Since then, the EPA Green Chemistry Program has built collaborations with academia, industry, other government agencies, nongovernmental organizations and international partners to promote pollution prevention through green chemistry.

As the report "Green Nanotechnology: It's easier than you think" (pdf) states: "Green nanotechnology offers the opportunity to head off adverse effects before they occur. Green nanotechnology can proactively influence the design of nanomaterials and products by eliminating or minimizing pollution from the production of the nanomaterials, taking a life cycle approach to nanoproducts to estimate and mitigate where environmental impacts might occur in the product chain, designing toxicity out of nanomaterials and using nanomaterials to treat or remediate existing environmental problems. Green nanotechnology does not arise de novo; rather, it builds on the principles of green chemistry and green engineering and focuses them through a new lens on the unique and often counter intuitive effects that occur in nanoscale materials.

Apart from the obvious areas of using nanomaterials in the areas of solar cells, biofuels and fuel cells, green nanotechnology applications might involve a clean production process, such as synthesizing nanoparticles with sunlight or the recycling of industrial waste products into nanomaterials, such as turning diesel soot into carbon nanotubes.

Implications of Nanotechnology for Environmental Health Research

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Nanotechnology is often described as an emerging technology—one that not only holds promise for society, but also is capable of revolutionizing our approaches to common problems. Nanotechnology is not a completely new field; however, it is only recently that discoveries in this field have advanced so far as to warrant examination of their impact upon the world around us.The value of nanomaterials in many technology areas is very high because of their versatile properties. As a result, the investment in nanotechnology by the U.S. government has had a very steady growth; in 2004 investment from a range of different federal agencies
reached nearly $1 billion, noted Kenneth Olden, National Institute of Environmental Health Sciences. Industrial investment in this area is also growing steadily. Today some nanomaterials are already being used commercially. For example, some companies are using TiO2 nanoparticles in sunscreen lotions because they provide transparency to a sunscreen, and are believed to be less toxic than the organic molecules currently used as UV absorbers in many sunscreen formulations.

Nanomaterials can also be found in sporting equipment, clothing, and telecommunication infrastructure. The future of nanotechnology is boundless, according to some speakers. Some of the items that exist today were a topic of science fiction a decade ago and have the potential to transform our society very quickly, said Douglas Mulhall, author of Our Molecular Future.Nanoparticles fall into three major groups: natural, incidental, and engineered, noted Vicki Colvin, Rice University. Naturally occurring nanomaterials such as volcanic ash, ocean spray, magnetotactic bacteria, mineral composites and others exist in our environment.
Incidental nanoparticles, also refered to as waste particles, are produced as a result of some industrial processes.

The third category of nanoparticles is engineered nanoparticles—these are the particles associated with nanotechnology. Engineered nanoparticles are subclassified by the type of basic material and/or use: metals, semiconductoris, metal oxides, nanoclays, nanotubules, and quantum dots. Within each category the shapes, sizes, and surface coatings further determine structure and function of these molecules. Each such material has been specifically designed for function, such as the fullerene C60, which is used for fuel cell applications. Very little is known about engineered nanoparticles and how they interact with cells or human organisms, noted Colvin.

Nano-biosystems

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Nano-biosystems is a field that includes both the use of nanotechnology in biological systems and utilization of biological or bio-mimetic techniques in nanotechnology. Nano-biotechnology shows a tremendous promise of improving the quality of life. For example, nano-vehicles might deliver drugs directly to targeted cells, nano-membranes may be used for development of cheap, effective water purification systems, or nano-chips that interface neurons with electronics may become common place. Additionally, Nano-Electro Mechanical Systems (NEMS) might use sensors and physical controls to stabilize individuals with heart, kidney or liver disease.

Impact of Nanotechnology on medicine

The impact of nanotechnology on cancer and other diseases depends on the design and
construction of devices to diagnose, treat, and monitor disease at all stages. In addition, new tools and devices are needed to understand the processes behind the development and
spread of a disease and to reverse or alter the progress of the disease.

Through a more comprehensive understanding of the bio-nano interface, nanomedicine will
mature into a higher-throughput and more predictable endeavor. This new branch of
medicine will revolutionize the way medicine is practiced, create a new pipeline of diagnostic
and therapeutic capabilities for the pharmaceutical industry, and catalyze extraordinary
advances in molecular and cell biology.

The most promising future nano science-based applications in medicine are
ultra sensitive and selective multiplexed diagnostics, drug delivery, targeted treatment of
cancer and other diseases, body imaging, tissue/organ regeneration, and gene therapy. All of
these applications combine engineering advances with improved strategies for manipulating
biological systems. New approaches for drug delivery, imaging, and diagnostics will be
refined and developed, and more sophisticated nano-therapeutics and diagnostics will
supplement those already in clinical use or in clinical trials. To facilitate this development, it
will be necessary to implement new manufacturing approaches. All new products must
address stringent safety and compatibility standards that are being challenged by the novel
properties of engineered nanomaterials and the potential that these may introduce new
biohazards.

Nanobiosystems design and applications

1. Functional nanomaterials
2. Inorganic/biologic hybrid composites and nanoparticles
3. Development of new technologies and tools for the detection, identification, quantification, and monitoring of molecules, cells and tissues of clinical and biomedical relevance.

Future Vision
 
  • Develop point-of-care nanodevices for early diagnosis and therapeutic response monitoring capable of using unprocessed bodily fluids with multiplexing and rapid analysis capabilities.
  • Develop diagnostic and post-therapy monitoring nanodevices for the detection and interrogation of circulating tumor cells and circulating tumor initiating cells.
  • Conduct successful clinical trials for nanoparticle delivery of siRNA molecules and other nucleic acid therapeutics.
  • Demonstrate novel nanoparticle-based drug formulations with significant improvement in targeting therapeutic windows as compared to free drug delivery.
  • Design particles to enable penetration of the blood-brain-barrier and enable more effective treatment of brain tumors.
  • Leverage nanotechnology-based studies of cell migration and cell motility for the development of anti-metastatic drugs.


Research Focus

Activities include the development of new technologies and tools for the detection, identification, quantification, and monitoring of molecules, cells and tissues of clinical and biomedical relevance. Research focuses in:
  • Micro-Nano systems for diagnosis.
  • On-chip environmental health monitoring.
  • Nano-Bio-Electronic Interfaces.
  • NanoBioFuel cells.
  • Nanobioelectrochemistry.

Nanostructured Materials

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Nanostructured surfaces can be broadly defined as substrates in which the typical features have dimensions in the range 1–100 nm (although the upper limit of 100 nm may be relaxed to greater sizes in some cases, depending on the material and the specific property being investigated). The recent surge of interest in these systems stems from the remarkable effects that may arise from the critical size reduction. Interesting novel properties (catalytic, magnetic, ferroelectric, mechanical, optical and electronic) occur as we reduce the dimensions from a practically infinite (and periodic) solid crystal to a system composed of a relatively small number of atoms. So far, nanostructured materials or nanomaterials are perhaps the only sub-field of nanoscience that has made the transition from fundamental science to real world applications, thus becoming a technology (a good example of this are nanostructured surface coatings)

Nanostructured Holograms:
Nanostructured Holograms for Broadband Manipulation of Vector Beams. Nanostructured device controls the intensity, phase, and polarization of light for wide applications in optics.Applied physicists at the Harvard School of Engineering and Applied Sciences (SEAS) have demonstrated that they can change the intensity, phase, and polarization of light rays using a hologram-like design decorated with nanoscale structures.

As a proof of principle, the researchers have used it to create an unusual state of light called a radially polarized beam, which—because it can be focused very tightly—is important for applications like high-resolution lithography and for trapping and manipulating tiny particles like viruses.This is the first time a single, simple device has been designed to control these three major properties of light at once.

Nanostructured carbon materials:
Irradiating solids with energetic particles is usually thought to introduce disorder, normally an undesirable phenomenon. But recent experiments on electron or ion irradiation of various nanostructures demonstrate that it can have beneficial effects and that electron or ion beams may be used to tailor the structure and properties of nanosystems with high precision. Moreover, in many cases irradiation can lead to self-organization or self-assembly in nanostructures. In this review we survey recent advances in the rapidly evolving area of irradiation effects in nanostructured materials, with particular emphasis on carbon systems because of their technological importance and the unique ability of graphitic networks to reconstruct under irradiation. We dwell not only on the physics behind irradiation of nanostructures but also on the technical applicability of irradiation for nanoengineering of carbon and other systems.

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