Nanotech, biotech research converging

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MCLEAN, Va., Oct. 15 (UPI) -- The difference between organic and inorganic materials and systems is slowly disappearing as scientists explore nanotechnology, researchers said Tuesday.

Nanoscience can manipulate matter as minute as individual atoms or molecules, the same level at which subcellular biological structures exist, said Nathan Swami, director of the Initiative for Nanotechnology in Virginia.

"The nanometer scale is the perfect scale for interacting with biological systems," Swami told a panel at the 2002 Virginia Biotechnology Summit.

A nanometer is to an inch what an inch is to 400 miles. The three main intersections between nanotech and biotech applications deal with structural, functional and manufacturing areas, Swami said.

As for structural uses, "our challenge is in making the leap from nanodevices (cells) to structural components (organs); biological systems have been doing that all along," said Emilie Siochi, a materials researcher at NASA's Langley Research Center in Hampton, Va.

If NASA can solve that transition, it stands a much better chance of engineering an aircraft wing that can mimic its bird counterpart's ability to adapt to changing conditions, she said.

One example of this work involves a polymer material that flexes in one direction when exposed to a positive voltage, and in the other direction for a negative voltage, Siochi said. The simplest version of this was considered for a type of "windshield wiper" to clean the optics of a proposed Mars lander, she said, but a more robust material could enable a wing to flex on command.

Other bio-inspired projects at NASA Langley include a self-healing polymer for instant repair of spacecraft skin, Siochi said, as well as heat-resistant materials for aircraft interiors that could prevent the spread of flame during an accident or crash.

Nanomaterials also show great promise when it comes to interfacing directly with living tissue, said Gary Wnek, chair of the chemical engineering department at Virginia Commonwealth University in Richmond. The extracellular matrix, or scaffolding, upon which all tissue is built consists of fibers between 20 and 100 nanometers in diameter, Wnek said, a size range nanoengineering should be able to replicate.

Work at VCU and other research institutions has shown collagen fibers comparable to ECM can be created through a technique called electrospinning, Wnek said. A strong electric current forces a syrupy solution through a tiny needle, and the resulting fibers whip back and forth in the shifting electric field, collecting on a rotating drum.

The process has turned out well-ordered collagen fibers about 100 nanometers in diameter, and living cells such as muscle tissue have grown properly on the matrix, Wnek said. Years of testing and Food and Drug Administration approval procedures are pending, he said, but the procedure could produce instant clotting agents to help stop bleeding or "living" blood vessel repair patches within a decade. More complex matrix material, such as for regrowing central nervous system tissue, is a long-term goal, he said.

A more immediate nano/bio application involves the sorts of metals and radioactive materials currently used in medical imaging and treatment, said Harry Dorn, a chemistry professor at Virginia Polytechnic Institute in Blacksburg.

Nanoscale collections of about 80 carbon atoms, called buckyballs, can encapsulate potentially toxic imaging agents, Dorn said. The contained materials enhance X-rays and magnetic resonance imaging scans without interacting with the body's cells, he said, and the buckyballs can hold more than one type of imaging agent, reducing the complexity of some medical tests.

The process, as with other promising nanoscale procedures, must undergo FDA tests, he said.