Nanoparticles To Analyse Blood

Photo: Laboratory staff working at a microscope

Ferrofluids are comprised of magnetic nanoparticles suspended throughout a liquid carrier. They have been used in industrial applications for years. Now a team of researchers has developed a biocompatible ferrofluid—one with the right pH level and salinity so that human cells can survive in it for several hours—and has created a device with integrated electrodes that generate a magnetic field pattern, allowing them to manipulate and separate red blood cells, sickle cells and bacteria contained in this unique solution.

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 they apply, the researchers are also able to manipulate and sort different types of cells depending on their size, elasticity and shape.

"It is like the cells are surfing on magnetic forces," lead researcher Hur Koser said. "When we turn on the magnetic field, the nonmagnetic cells are pushed immediately up to the top of the channel." There, they roll along the surface and can be quickly directed toward a sensor.

Being able to effectively sort and move cells with this technique could allow for much greater efficiency in disease detection by directing diseased cells toward sensors. 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.

Koser hopes that one day the new technique will lead to portable sensors that doctors can carry into the field and which could be used to test for a range of disorders, such as cancer and HIV. "Anything you can put into the ferrofluid solution is potentially detectable in this manner."; Source: Yale University