Diagnostic gadget mixes and matches all in one.

Researchers at Motorola Labs in Tempe, Ariz., have created a miniature diagnostic lab that can detect specific disease-linked genes in a small sample of whole blood.

Numerous groups are developing chips that can detect tiny amounts of disease-related molecules, most notably DNA. However, the DNA typically has to be removed from the cells and purified using other laboratory instruments before the chip can detect it, says Robin Liu, who helped develop the device.

In the new scheme, when the researchers add a milliliter sample of blood to the system, the device itself processes the blood by shuttling it through microscale channels into various reaction chambers. The first chamber isolates the cells from the rest of the sample. A second chamber breaks open the cells, and then a chemical mixture pumped into the chamber makes multiple copies of the now-accessible DNA. The genetic material then passes into the final chamber.

There, a series of DNA probes fish out disease-related genes and produce electric signals that indicate whether the blood test is positive or negative for those genes. The entire assembly fits onto a thin platform the size of an index card.

The portable lab can produce results in two and a half hours, but with improvements, Liu says it could take less than an hour. The researchers describe their diagnostic device in the April 1 issue of Analytical Chemistry.--A.G.