Thursday, April 7, 2005

DNA Chip Goes Wireless

Filed under: Genetics

MIT Technology Review reports:

Context: DNA chips for detecting genetic variations abound. Typically, a processed biological sample is placed on a chip, which then must be loaded into a separate, expensive device for reading. Now, Yoshiaki Yazawa and colleagues at Hitachi have designed a tiny chip that not only detects DNA variation but can report it wirelessly from the inside of a sealed sample container. These chips could be dropped directly into a solution containing copies of patient DNA and should be cheap enough to be disposable.

Methods and Results: The chip packs a biosensor, radio transceiver, and antenna coil onto 2.5 by 2.5 millimeters of silicon. An off-the-shelf external unit powers the chip with radio waves and reads its transmissions. To detect a particular DNA ­sequence, researchers add the complementary sequence to the sample along with the chip. If DNA in the sample binds to the probe sequence, an enzyme emits light. When the sensor on the chip detects the change in light, the radio unit sends a signal to the external unit.

This is a simpler technique than the one used by most other chips, which requires fluorescent dyes, lasers, and microscopes. Additional chips can be added to the sample to boost accuracy or to detect different kinds of variations. Hitachi researchers believe that up to 100 variations could be measured at one time. Also in development are wireless sensors that use the same technology to monitor temperature and pH, which could enable better control of experimental conditions and thus more reliable readings.

The MIT Technology Review article also explains the implications of such technology.

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