A research team led by Chad A. Mirkin, director of Northwestern's Institute for Nanotechnology, has invented a technique for creating thousands of DNA detection probes made of gold nanoparticles with individual molecules attached. Much like human fingerprints, these molecules act as unique signals for the presence of different biological agents. The new detection method, for instance, can easily distinguish smallpox's distinct "fingerprint" from that of HIV.

"By providing a near infinite number of signals, this advance allows researchers to quickly and accurately screen a sample for an extraordinarily large number of diseases simultaneously," said Mirkin, also George B. Rathmann Professor of Chemistry.

Results, which include testing for genetic markers for six biological agents including hepatitis A, smallpox and HIV, will be published in the Aug. 30 issue of the journal Science. The new technology, which takes advantage of a technique called Raman spectroscopy, improves upon optical detection methods reported previously by Northwestern in Science.

Mirkin's group has been pioneering the use of nanoparticles as a potential replacement for the more expensive polymerase chain reaction (PCR) and conventional fluorescence probes, the most widely used detection technology. It currently take days and sometimes weeks for results of genetic screening and disease diagnosis to come back from the laboratory.

"PCR was an extraordinary advance in diagnostics, but its complexity prohibits the development of easy-to-use diagnostic systems that can produce quick results in the field or in the doctor's office," said Mirkin. "Once a disruptive technology like PCR is invented, it creates a challenge for
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Contact: Megan Fellman
fellman@northwestern.edu
847-491-3115
Northwestern University
29-Aug-2002