SCIENCE & TECHNOLOGY
DIAGNOSTIC DEVICE HEADS TO FIELD
SAMUEL SIA
with samples from patients recently diagnosed using lab-based tests. Out of 70 specimens from people with known HIV status, only one tested false. In another study, they used mChip for a combined HIV-syphilis test. The results were as good as those obtained with lab-based immunoMICROFLUIDICS-BASED TEST for HIV and assays, with the test for HIV syphilis rivals lab-based tests being more sensitive and specific than the one for syphilis. A NEW MICROFLUIDICS-based diagnostic For their test case, Sia and The disposable mChip test performs as well as the gold-standard coworkers detected protein “both is simple and carries lab-based test at a fraction of the cost, its markers of HIV and syphilis out the assays well,” says developers say. They used their “mChip” in 1 μL of whole blood in an Paul Yager, an engineering to detect HIV and syphilis in Rwanda (Nat. injection-molded plastic professor at the University Med., DOI: 10.1038/nm.2408). device. They delivered the 14 of Washington who is also Despite the many advances that researchreagents—antibodies, washdeveloping microfluidic ers have made in microfluidics, few of those ing solutions, and signaldiagnostics. But, Yager also advances have been integrated into a single development solutions— notes, “a bit of support device that is suitable for use in limitedneeded for the assay using equipment in a permanent resource settings in Africa and elsewhere. plugs of liquid separated by instrument is necessary to To make the mChip, Samuel K. Sia, a proair spacers. As the solution make the disposable work. TIGHT TURNS Researchers use this device to diagnose fessor of biomedical engineering at Columflows through detection My own preference these HIV and syphilis. Shown bia University, and coworkers combined regions on the mChip, antidays is to drop the instruhere is a close-up of the advances in manufacturing, fluid handling, bodies on the channel surment entirely.” detection zone. The channel and signal detection into a single device. face capture protein disease is 120 µm wide. Sia is working with “Integration has been one of the most markers from the blood. The Claros Diagnostics, which difficult challenges” in making field-ready researchers amplified the he cofounded in Woburn, microfluidic devices, Sia says. “We have signal using the reduction Mass., to commercialize the found that it’s not enough to have a better of silver ions onto antibody-tethered gold device and assays. “Unfortunately, the reamplification procedure, or a new method nanoparticles. The signal can be observed turn on investment for many global health for handling fluids, or a better capture visually or with an inexpensive optical diseases is not attractive for investors, so molecule. The real proof is whether we can device. The total cost of materials and rewe probably need some involvement from put together an integrated test that can run agents is only 10–20 cents per test, Sia says. philanthropy to commercialize a global from start to finish an accurate assay using Working with clinical collaborators in health infectious-disease test,” Sia says.— real clinical specimens.” Rwanda, the team evaluated the device CELIA ARNAUD
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