News FocusMATERIALS RESEARCH SOCIETY FALL MEETING

Protein Chip Promises Cheaper Diagnostics

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Science  19 Dec 2008:
Vol. 322, Issue 5909, pp. 1784-1785
DOI: 10.1126/science.322.5909.1784b

MATERIALS RESEARCH SOCIETY FALL MEETING, 1-5 DECEMBER, BOSTON

Ever since recent advances made it possible to study thousands of genes and proteins at once, researchers have dreamed of nipping diseases in the bud by spotting telltale proteins with simple blood tests. So far, that vision remains a long way off. Few individual proteins in blood and tissues have proven to be conclusive indicators of disease. Even if they were, clinical lab tests that measure proteins don't come cheap. Standard diagnostic panels can cost $50 each or more. At that price, scanning millions of patients for dozens or more proteins would cost a fortune. But new glass and plastic microfluidic chips could begin to change that equation.

At the meeting, James Heath, a chemist at the California Institute of Technology (Caltech) in Pasadena, reported that his team has made microfluidic chips that can detect and quantify levels of a dozen different proteins in blood plasma simultaneously. What is more, the test needs only a single drop of blood, which it can analyze in less than 10 minutes. Because such chips are cheap and easy to manufacture, they could drop the lab costs to just pennies per test, Heath says.

“If we can develop simple devices [for finding disease markers in plasma], that could be a big development for global health,” says Samir Hanash, a proteomics expert at the Fred Hutchinson Cancer Research Center in Seattle, Washington. Still, even though this new device makes strides toward that goal, he cautions that proving the device can work reliably under a wide range of conditions remains a distant prospect.

Quick scan.

A new biochip analyzes a single drop of blood plasma for up to a dozen different protein indicators of disease. Because the new chips are cheap and fast, they could revolutionize medical diagnostics.

CREDIT: R. FAN ET AL., NATURE BIOTECHNOLOGY (ADVANCE ONLINE PUBLICATION) © 2008 NATURE PUBLISHING GROUP

In coming up with their new chip, Heath's team combined recent innovations in microfluidic chips and DNA arrays, both of which have been advancing rapidly in recent years. The Caltech researchers used standard microfluidic chip-patterning techniques to carve a series of large and small channels in a thin polymer film. Then they bonded the film to a glass slide patterned with 12 strips of antibodies to specific proteins. The resulting device separates blood plasma from whole blood cells, then steers the plasma and the proteins it contains over the antibody arrays for analysis. Fluorescence analysis then reveals any proteins bound to the array, creating a bar-code readout of which proteins are present from each blood sample. When different concentrations of the same antibodies are placed on different strips, the chips can also determine the abundance of target proteins as well.

Using their new chip, the members of the Caltech team showed that they could sort 22 cancer patients into different groups based on which of 12 different proteins associated with cancer were in their blood. Heath says he and his colleagues have formed a company in hopes of commercializing the technology.

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