In the battle against cancer and other diseases, precise analysis of specific proteins can point the way toward targeted treatments. Scientists at theTechnische Universitaet Muenchen (TUM), together with Fujitsu Laboratories of Japan, have developed a novel biosensor chip that not only recognizes proteins that are characteristic for specific diseases, but also can show if these proteins are changed through the influence of disease or drugs.
The human immune system recognizes pathogens by specific proteins on their surfaces. This detection principle manifests itself again and again in biology, and it is already used in medical tests. Such tests typically require relatively large amounts of sample material, however, and many problems can't be investigated in this way. For some tests, the target protein must be chemically modified by reagents. That requires both time and well trained lab technicians. Now scientists at TUM's Walter Schottky Institute have developed a biosensor one hundred times more sensitive than currently available tests in recognizing proteins that are characteristic for the clinical picture of specific diseases.
The biosensor chip holds synthetic DNA molecules, which are negatively charged, in an aqueous salt solution. These long molecules are tethered at one end to a gold surface. The free end is labeled with a fluorescent marker, so it can be optically observed; and at the very tip the scientists can place a "capture probe," a molecule that fits together with the target protein like the key to a lock. Alternating electric potentials set the DNA molecules in motion, swinging back and forth between "standing" and "lying" states with regular changes in a tightly confined but intense field. If the protein of interest is present in sample material placed on the biosensor chip, it will bind to the "key" molecule. And because this makes the DNA strands considerably heavier, their swinging motion will be noticeably slower. Preci
|Contact: Andreas Battenberg|
Technische Universitaet Muenchen