New Chemical Sensors Could Speed Up Research

Reusable chemical sensors under development may allow simultaneous detection of numerous chemicals in a sample 100 or 1,000 times smaller than a drop of water, greatly speeding the work of clinical, pharmaceutical, or environmental laboratories. The research is being conducted by chemists at the University of Buffalo (UB, New York, USA).

The new technology is based on xerogels, developed through sol-gel processing in which a special solution reacts to form a porous polymer. A xerogel is a rigid material but consists of an intricate network of nanoscopic pores. The UB researchers have developed new ways to stabilize and trap proteins within the xerogels, which can then be used to signal the presence of chemicals in a sample. However, the xerogels are large and detect only one chemical species. So the researchers sought a way to shrink all the sensor technology so they could place multiple sensors in a small area and obtain information on many chemicals in a single, small sample. After many different attempts, they found that pin-printing produced a solution.

In pin-printing technology, used in genomics, an extremely thin pin point uses capillary action to suck up small volumes of solution and then deposits or prints them onto microscopic slides. Using a commercial pin-printer, similar to those in DNA microarray facilities, the researchers found they had solved the problem. They contact-printed the sol-gel solution directly on the slide surface to form an array of xerogel-based sensors.

"Because the volume delivered by these pin-printers is less than a trillionth of a quart, the sensors are very small, so we can cram many different sensors in a small footprint and, in principle, detect hundreds or even thousands of chemical species simultaneously,” said Frank V. Bright, Ph.D., co-author of an article on the research appearing in the March 1, 2002, issue of Analytical Chemistry. Dr. Bright is associate chair and professor in the UB department of chemistry.

The research team is now working on pin-printing chemical sensors onto the top of an light emitting diode (LED) to form a fully self-contained sensor array platform.




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