Indian Americans in Frontline Nanotechnology Research  
by: Francis C. Assisi

Boston, 4 May: Well over $4 billion annually is now being invested worldwide in nanotechnology research by governments and major corporations. This investment is creating a rich body of nanotechnology, much of which will be commercialized in the next ten years.

Already, Indian American scientists and engineers are initiating a chain of innovation and entrepreneurship, which is taking new discoveries from science to technology to product to business in this emerging field. No wonder that a star investor such as Vinod Khosla of Kleiner & Perkins is taking a closer look at nanotechnology.

Patents in Nanotechnology

A recent survey by this correspondent shows that Indian Americans are walking away with a large chunk of inventions in nanotechnology -- as acknowledged by the United States Patent Office. For example, consider this: Tapesh Yadav, Founder and CEO of NanoProducts Corporation (Longmont, Colorado), has 28 issued and allowed patents on nanotechnology, and over 30 pending patents. Nine of those patents were obtained last year alone. A key contributor to the field while at MIT, Yadav recently demonstrated the feasibility of small, lightweight sensors that exploit the unique characteristics of nanoceramics in advanced aircraft engines, for a project at the NASA Lewis Research Center.

NanoProducts researchers have begun work on nanoscale devices that may lead to the formation of "plastic" circuit elements and circuit "sheets" fabricated with ink jet printers within three years. "The first generation of nanotechnology will just be performance enhancements to existing micromaterials-significant performance enhancements-but it´s the second generation, in about three years, that will start employing nanomaterials in much more significant quantities," said Yadav.

The lab fabricates nanoscale materials using the company´s patented Joule-Quench fabrication process, whereby powders whose grains are smaller than 100 nm in diameter are mass-produced.

"We can make nanoscale materials conducting or insulating or magnetic or with any of the properties that electrical engineers use to build devices, like dielectrics. We have a dielectric powder you could make capacitors with," said Yadav. He said the company´s subsidiary research lab is making actual devices like capacitors, inductors and resistors using technology based on its patents. "Just making the powder is not good enough; you have to know how they perform, so you can learn from that."

In the Joule-Quench process, a combustion of a precursor creates a stream that is heated into a plasma exceeding 3,000 K, after which cooling leads to nucleation (formation of nanoparticles). Sonic quenching is used to eliminate "sticky" collisions, thereby producing a steady stream of nanopowders.

According to Yadav, those materials are already being incorporated into current devices to enhance the characteristics of micron-sized materials. For the future, the lab is working on a variety of traditional electronic devices based on nanoscale materials that will enable them to be printed with ink jet printers or incorporated into layered composites.

Paras Prasad’s Book On Nanophotonics

Last month also saw the release of the first book on Nanophotonics (John Wiley & Sons) -- the science behind light and matter interacting on the nanoscale – authored by Paras Prasad, SUNY Distinguished Professor in the Department of Chemistry at the University at Buffalo and executive director of UB´s Institute for Lasers, Photonics and Biophotonics, Nanophotonics.

Prasad says his objective is to interest young, as well as established, scientists about the potential that awaits them in nanophotonics research.

"We are living in an age of ´nano-mania,´" writes Prasad, "when everything nano is considered to be exciting and worthwhile." He points to the many government attempts worldwide to pour investments into nanotechnology research, as well as optimistic market projections.

Prasad, one of the earliest pioneers in photonics, is known for his work developing novel photonic materials with applications ranging from information storage to photodynamic cancer therapy and bioimaging, as well as the recent development of magnetic "nanoclinics," thin silica bubbles that can target cancer cells.

Meanwhile, the extent and pace at which Indian American scientists and engineers are involved in frontline nanotechnology research can be assessed from two important advances reported in April 2004.

Textile Fibers With Nanotechnology

Now that nanotechnology is at a defining point, its worth considering what Satish Kumar, a professor in Georgia Tech´s School of Polymer, Textile and Fiber Engineering has to say about a new class of textile fibers he is working on: "In 1900, nylon, polyester, polypropylene, Kevlar and other modern fibers did not exist, but life today seems to depend on them. The rate at which technology is changing is increasing, so much more dramatic changes can be expected in the next 100 years. Every major polymer fiber company in the world is now paying attention to the potential impact of carbon nanotubes."

Kumar expects composite fibers based on carbon nanotubes to offer improved mechanical & electrical properties and bring about the most significant changes to the textile industry since synthetic fibers were introduced in the 1930s.

Kumar is of the opinion that carbon nanotube reinforced composites could ultimately provide the foundation for a new class of strong and lightweight fibers with properties such as electrical and thermal conductivity unavailable in current textile fibers.

He’s been working on such a project with researchers from the Georgia Institute of Technology, Rice University, Carbon Nanotechnologies, Inc. and the U.S. Air Force to develop new processes for incorporating nanotubes into fibers and films. The results were presented March 28 at the 227th national meeting of the American Chemical Society in Anaheim, Calif.

"We are going to have dramatic developments in the textile materials field over the next 10 or 20 years because of nanotechnology, specifically carbon nanotubes," predicted Kumar. "Using carbon nanotubes, we could make textile fibers that would have thermal and electrical conductivity, but with the touch and feel of a typical textile. You could have a shirt in which the electrically-conducting fibers allow cell phone functionality to be built in without using metallic wires or optical fibers."

Thanks to the work of Kumar and researchers at the Air Force Research Laboratory, nanotubes have already found their way into fibers known as Zylon, the strongest polymeric fiber in the world. By incorporating 10 percent nanotubes, research has shown that the strength of this fiber can be increased by 50 percent.

Recently, Kumar´s research team has been collaborating with Richard Smalley, a Rice University professor who received a 1996 Nobel Prize for his work in developing nanotubes, which are of great interest because of their high strength, light weight, electrical conductivity and thermal resistance.

In addition to aircraft structures, Kumar sees nanotube composite fibers bringing electronic capabilities to garments, perhaps allowing cellular telephone or computing capabilities to be woven in using fibers that have the touch and feel of conventional textiles.

Enzyme-based Nanomanufacturing

Ashutosh Chilkoti of the Center for Biologically Inspired Materials and Material Systems, at Duke University has a reputation as a speedy inventor. In about seven years at the University, he has obtained patents for five of his inventions, including one that targets cancer drugs to tumors using heat-sensitive polymers.

Last month, the Indian American biomedical engineer announced an important advance in nanomanufacturing by demonstrating that enzymes can be used to create nanoscale patterns on gold.

Enzymes are nature´s catalysts -- proteins that stimulate chemical reactions in the body and are used in a wide range of industrial processes, from wastewater treatment to cheese making to dissolving blood clots after heart attacks. Since many enzymes are already commercially available and well characterized, the potential for writing with enzyme ‘ink’ represents an important advance in nanomanufacturing.

In their experiments, the engineers used an enzyme called DNase I as an "ink" in a process called dip-pen nanolithography -- a technique for etching or writing at the nanoscale level. With the dip-pen they inscribed precise stripes of DNase I ink on a gold plate, which they had previously coated with a thick “forest” of short DNA strands. The stripes of the enzyme were 100 nanometers wide -- about one millionth the diameter of a human hair.

Once the researchers had created the stripes, they then activated the enzyme with a magnesium-containing solution. This changed the DNase I into a form that efficiently breaks down any DNA in its path. As a result, the team reports in the May 2004 issue of the Journal of the American Chemical Society, available online as of March 27, 2004, the stripes of activated enzyme carved out “troughs” in the DNA coating that were 400 nm wide.

“We were surprised that the enzyme ‘ink’ worked so well, because it was simply deposited on the surface and could have washed away during the processing steps,” said Chilkoti, who directed the project.

Chilkoti credits much of the experiment’s success to the laboratory skills of Jinho Hyun, who was a post-doctoral fellow in his group, and who is now an assistant professor at Seoul National University. But this experiment was also an important proof of principle, said Chilkoti. Until now, few researchers have explored biological substances for nanoscale manufacturing, and even fewer have taken the approach of putting down chemically active biomolecules on a surface.

“A lot more work is needed to optimize the process, but we feel this enzyme-inking technique has tremendous promise for wide applicability,” said Chilkoti.

Enzyme-based nanomanufacturing is of interest because it could be an incredibly versatile tool. “This is critical because nanomanufacturing is at the heart of efforts to see if we can make new devices that are far smaller, cheaper, faster and better than existing devices,” said Chilkoti.

To date, dip-pen nanolithography has been primarily a bench-top laboratory technique. Scaling up the technique to truly make it a viable manufacturing technique will require new instrumental technology, such as dip-pen lithography machines with multiple, articulated tips that can move independently to deposit several different types of enzymes.

Chilkoti envisions machines that can work on a sheet of chips using different enzymes, so that the chips can be snapped apart after the enzyme inking and processing. Chilkoti notes that such machines are already being commercially developed, so the day might not be too far off when enzyme based nanomanufacturing might be possible on an industrial scale

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