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Laboratories-on-a-chip foil terrorism

A laser lights up a biochip in the Argonne-developed portable reader that Susan Hammond is testing. One day this system may detect airborne pathogens.

Laboratories-on-a-chip developed at Argonne can detect chemicals, bacteria or viruses that terrorists may use. The agents can be detected in less-than-lethal amounts and used to trigger alarms or detoxification systems that the laboratory is also developing.

One chip would be able to identify a range of agents more quickly than devices that have been in use.

A nose for poison

Argonne has developed a miniature "microelectronic nose" that detects chemical poisons such as cyanogen chloride and hydrogen cyanide gases at nonlethal concentrations. It is being trained to detect VX, sarin and mustard gases as well. The prototype instrument fits in the palm of a hand.

The microelectronic nose employs solid state ceramic-metallic materials. Its sensor arrays are smaller than postage stamps and inexpensive to make using established fabrication techniques. The package can be incorporated into personal monitors or installed at fixed positions in buildings. The sensor received an R&D 100 Award from R&D magazine in 2002.

The sensing capability is based on the distinct electronic "fingerprint" that each compound yields when in contact with the sensor. Each chemical reacts uniquely with the sensor's surface, changing the electrical resistance of its components. An attached computer or microcontroller analyzes these resistances in the form of wave patterns to identify the chemicals present. The location and magnitude of features in the patterns determine the presence and concentration of each chemical.

By passing minute quantities of known chemicals over the sensors, the computer is trained to recognize these patterns. Funding was provided by the Department of Defense, General Atomics and Relative Solutions Corp.

Argonne's biological chips detect agents

Argonne's biochip can be used to detect biological agents. A biochip is a small glass slide with up to several thousand 3-D gel pads mounted on its surface. Each gel pad is similar to a micro-test tube. Robots developed at Argonne can load the pads with DNA or protein fragments specific for individual bacteria, viruses or chemicals. Computers then read and interpret the results of any reactions.

Researchers in Argonne's Biochip Technology Center are developing new applications for the biochip, writing faster sample analysis programs, and working to shrink portable biochip readers.

These biochips, called MAGIC chips, short for "Micro Array of Gel-Immobilized Compounds"--can perform thousands of tests per hour, and they can be cleaned and reused dozens of times. In the laboratory, they have successfully detected pathogens from bacteria that do not cause disease or illness in healthy people but are closely related to bacteria that do. The chips also have decoded complex DNA strands. The chips have distinguished quickly among strains of tuberculosis, and Argonne is working with the State of Illinois to adapt them for forensic DNA testing.

Other applications that researchers have found for MAGIC chips include gene expression, especially responses to mutations, diagnosis and monitoring of genetic diseases, microbial analysis in environmental cleanups and agriculture, routine protein analysis of blood and urine, and exploration for life in outer space.



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