Paper blood test for the Third World

DIAGNOSTICS

In the developing world, providing a basic, affordable blood test is often difficult. There is widespread need for medical diagnostics that are rapid, inexpensive, and portable, without the need for an expansive laboratory setting.

Now, George Whitesides' laboratory in the Department of Chemistry and Chemical Biology at Harvard may have engineered a technological solution - from paper.

"We wanted to develop a diagnostic device from something that cost as little as possible," says first author Andres Martinez, a graduate student. The group chose paper because it is not only cheap, but readily available and can filter fluids such as blood, water, and urine without requiring external pumps or power.

The research group uses a technology called photolithography - literally meaning writing on stone with light - to imprint channels into the paper that can move fluids along a specific course. As a result, placing a single drop of blood on the paper can carry the sample along different routes, allowing multiple diagnostic tests to be run simultaneously.

One other advantage: paper burns. "Once we've put a patient's blood on the device, its biohazardous. It's easily disposable if you light a match," says Martinez.

Martinez says they hope to use the device to target prevalent and preventable diseases such as HIV, tuberculosis, and malaria. BOTTOM LINE: A new paper-based device can allow multiple diagnostics to be performed at very low cost.

CAUTIONS: High humidity and high temperatures could affect the way certain fluids move through the paper.

WHAT'S NEXT: "We're working on designing applications for the device to test for diseases like HIV and malaria," says Martinez.

WHERE TO FIND IT: The Proceedings of the National Academy of Sciences, Dec. 8, 2008.

SUSHRUT JANGI

DIABETES

Black women who exercised more and watched television less had a lower risk of developing type 2 diabetes than other similar women, a 10-year study from Boston University shows.

African-American women become type 2 diabetics at twice the rate of non-Hispanic white women, lending urgency to finding ways to prevent the disease.

Previous clinical trials have shown that women who are physically active are less likely to become diabetic than sedentary women, but the numbers of black women in those studies have been too small to make a strong connection.

Julie R. Palmer and her BU colleagues report that among more than 45,000 women in the Black Women's Health Study, those who engaged in vigorous activity for more than seven hours a week or walked briskly for more than five hours a week were less likely to become diabetic than women who were not physically active. Watching television for more than five hours a day was linked to more cases of diabetes compared with less than one hour a day of TV viewing, whether the women exercised or not.

BOTTOM LINE: More time walking briskly and less time watching television were each linked to lower rates of type 2 diabetes in a large trial of African-American women.

CAUTIONS: Physical activity was self-reported.

WHAT'S NEXT: These results provide a scientific foundation for educating African-American women about the power of physical activity to prevent type 2 diabetes.

WHERE TO FIND IT: Online in the American Journal of Epidemiology.

ELIZABETH COONEY