Self-assembled tubes for electronic devices.

• Position: Nanotechnology - Brief Article

Tiny self-assembled tubes, about one-one thousandth the width of a grain of sand, may now be used as a scaffold to custom-build molecular wires and other components for use in nanometer-sized electronic devices, including some that could be inserted into the body. Researcher Hicham Fenniri of Purdue University, West Lafayette, Ind., has developed a method to create self-assembling nanotubes that can be easily manipulated with specific dimensions or chemical properties. Like molecular-sized Tinkertoys, the nanotubes can be used as a frame on which various objects--in this case chemicals, molecules, or even metals--can be added to give the structure a specific property or direct it toward a selected target, he says. Tailoring structures in such ways will allow scientists to develop high-performance materials or new tools to diagnose and treat disease.

"By using different chemicals on the outside of the structure, you can modify its function or make it bind to a specific target, such as an amino acid," Fenniri notes. "It's like we have a skeleton, and we just have to put a dress on it. And we can decorate the tube with all sorts of dresses."

The structures developed using Fenniri's self-assembling system may prove to be especially useful in industrial applications because they are able to remain stable under high temperature conditions. The tiny structures, fueled by hydrophobic attractions between the molecules, actually increase in size under high temperatures. "This opposes common wisdom, because generally when you heat something, it falls apart. Our demonstrations show that these structures become more stable under the influence of temperature and attain a new level of self-organization." The findings may pave the way for designing new materials, electronic devices, and drug delivery systems for use in the atom -size realm of nanotechnology. The idea of using very small components, or nanotechnology, to make computers and electrical devices--including biomedical devices that could be inserted into the body--has been the subject of much scientific interest...