A new device about the size of a business card, developed by scientists at the Methodist Hospital Research Institute and MD Anderson Cancer Center, Houston, TX, could let health care providers perform up to 50 tests for insulin and other blood proteins, cholesterol, and even viral or bacterial infection all from one drop of blood.

The V-chip, short for "volumetric bar-chart chip," is composed of two thin pieces of glass, about 3" x 2" surrounding wells for four things: hydrogen peroxide; up to 50 different antibodies to specific proteins, DNA or RNA fragments, or lipids of interest, and the enzyme catalase; serum or other sample; and a dye. Initially, the wells are kept separate from each other. A shift in the glass plates brings the wells into contact, creating a contiguous, jagged space from one end of the V-chip to the other.

As insulin, for example, binds to antibodies bound to the glass slide, catalase is made active and splits nearby hydrogen peroxide into water and oxygen gas. This approach is called an enzyme-linked immunosorbent assay. The oxygen pushes the dye up the column. The more insulin is present, the more oxygen is created, and the farther dye is pushed up the slide. The end result is an easy to read bar chart.

The researchers plan to continue to develop the device for even easier use and wide distribution.

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