December 16, 2009

2 Min Read
Magnetizable Liquids May Enhance Sensitivity of Disease Detection Devices



Yale researchers have developed a unique approach to sorting and manipulating cells for disease detection.

Manipulating magnetic forces is becoming all the rage in medical research these days, including using magnets for microfluidic connectors. Finding the idea of innovating disease detection attractive, a team of scientists from Yale University (New Haven, CT) has employed magnetizable liquids to rapidly manipulate and sort various cells. The researchers speculate that this technique could improve the speed and sensitivity of tests for a host of diseases and disorders.The cell manipulation process relies on the use of biocompatible ferrofluids, which consist of magnetic nanoparticles suspended throughout a liquid solution, and a device designed with integrated electrodes. Attracted to the magnetic field generated by the electrodes, the ferrofluid-based nanoparticles gravitate toward it, consequently forcing the nonmagnetic cells to move along specific channels."It's like the cells are surfing on magnetic forces," explains Hur Koser, associate professor at the Yale School of Engineering & Applied Science. "When we turn on the magnetic field, the nonmagnetic cells are pushed immediately up to the top of the channel." Cells can be sorted based on size, elasticity, and shape, depending on the frequency applied, according to the team.Unlike other cell manipulation processes, the Yale technique doesn't involve the attachment of biomarkers or labels to the cells and neither extensive preparation nor postprocessing is required. More importantly, however, it could expedite and improve diagnostic tests for such diseases as cancer and HIV. For example, current tests may take hours or days to yield results because the concentration of the disease in a given sample may be so low that it takes a significant amount of time to randomly make contact with a sensor. With this technique, however, the nonmagnetic nanoparticles are quickly attracted to the applied magnetic field, thereby effectively ushering the potentially diseased cells directly toward a sensor.The researchers hope that this efficient approach could ultimately improve the sensitivity of existing detection technologies by several orders of magnitude. Potentially able to manipulate and sort red blood cells, sickle cells, and bacteria in a sample, the technology could also allow for the eventual development of portable sensors designed for physicians to bring into the field for point-of-care detection and diagnosis.View the researchers' video demonstrating how microparticles can be directed to specific channels in the ferrofluid.

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