Cells in Blood Manipulated and Sorted Via Ferrofluids

Technology that uses magnetizable liquids (ferrofluids) to rapidly manipulate and sort different cells in blood, could dramatically improve the speed and sensitivity of tests used to detect cancer biomarkers, blood disorders, viruses, and other diseases. The new method does not require attaching biomarkers, or labels to the cells thus eliminating labor-intensive preparation or postprocessing.

Ferrofluids comprise magnetic nanoparticles suspended throughout a liquid carrier. A biocompatible ferrofluid--one with the right pH level and salinity so that human cells can survive in it for several hours—was developed together with a device that has integrated electrodes that generate a magnetic field pattern.

The magnetic field attracts the nanoparticles in the ferrofluid, effectively pushing and shuffling the much larger, nonmagnetic cells along specific channels. Depending on the frequency of the magnetic field applied different types of cells are manipulated and sorted according to their size, elasticity, and shape.

Being able to effectively sort and move cells with this technique could allow for much greater efficiency in disease detection. Many of today's tests require hours or even days to complete, because the concentration of diseased cells in a blood sample may be so low that it takes a long time for them to randomly bump into the sensors. For example, in early-stage cancer there could be one tumor cell for every billion healthy cells, making the cells extremely difficult to detect.

The new technology was developed by a team of scientists led by Hur Koser, associate professor at the Yale School of Engineering & Applied Science (New Haven, CT, USA) together with colleagues at the Deutsches Elektronen-Synchrotron (DESY; Hamburg, Germany) and University of Georgia (Athens, GA, USA). The findings were published in the December 7, 2009 online edition of the Proceedings of the National [U.S.] Academy of Sciences (PNAS).

Related Links:
Yale School of Engineering & Applied Science
Deutsches Elektronen-Synchrotron
University of Georgia