Tiny Tool May Boost Detection of Diseases

Scientists have developed a new tool for detecting infectious disease that, some experts said, could significantly enhance the containment of epidemics or the early warning of bioterrorist attacks.

The method, developed by Chad A. Mirkin of Northwestern University’s Institute for Nanotechnology and announced Thursday, is another step in commercial applications of the growing science of nanotechnology, which uses tools as small as a few molecules.

The new method, which uses probes more than 700 times thinner than a human hair, could make it much easier to detect the most minute traces of infection involving anthrax, smallpox, HIV, AIDS, tularemia and other microbes, Northwestern researchers said. The method is far more refined than conventional tools and much less expensive and can deliver results in a few hours rather than days or weeks, they said.

“This is a very significant breakthrough,” said Charles Martin, director of research at the University of Florida Bio/Nano Interface center. Martin reviewed the Northwestern researchers’ article on the technology, which appeared in Thursday’s edition of Science magazine. “The science is sound,” he said.

A spokeswoman for the Air Force Office of Scientific Research, one of several agencies funding the research, said the science was promising and could have many applications.

Nanosphere Inc., a Northbrook, Ill., company, has licensed the technology and said it could be used commercially not only in disease detection but also in drug development, clinical tests performed in laboratories and hospitals, and for use by the military.

The technology, Mirkin said, uses probes made of gold particles. Attached to the particles are individual molecules that provide a unique signal, or fingerprint, when a light is shone on them. The molecules can signal the presence of different biological agents, easily distinguishing the virus that causes smallpox from HIV. Also attached to the particles are signal strands of DNA designed to recognize and bind to a target, such as the smallpox or hepatitis A viruses.

This method, Martin said, allows for simultaneous testing of many different types of diseases more accurately and quickly. The difference in refinement of what can be detected, another expert said, could be compared to the video capability of an old computer, which could produce only as many as 256 colors, versus a more modern one capable of 16 million colors.

A Nanosphere machine that is using the technology is the size of a large bagel toaster. For nonhuman tests not requiring Food and Drug Administration approval, the company could have products ready to market by next year, said Vijaya Vasista, who is in charge of the project for Nanosphere. Diagnostic tests on humans would require FDA approval, and the company would have to prove its system is superior to existing ones.

Roy Doumani of the California NanoSystems Institute, a partnership between UCLA and UC Santa Barbara, said transforming such sophisticated science into a commercially viable product will be difficult.

Carbon nanotubes, for example, were invented in 1991 and are many times lighter and stronger than steel, Doumani said.

“But they still can’t be produced at a price that makes them viable,” he said.