February 23, 2012
New Device Could Help Isolate, Capture Target Cells
Researchers from MIT, Harvard Medical School (HMS) and Massachusetts General Hospital (MGH) have developed a new device that they say will make it easier to find specific cells in complex mixtures such as blood samples -- a discovery that could make it easier to diagnose and treat diseases.
"Researchers have used a number of techniques to sort cells based on differences in size, density or electrical properties," Anne Trafton of the MIT News Office said in a Wednesday report. "However, since the physical characteristics of cells can vary significantly, these techniques risk separating cells incorrectly, leading to an erroneous diagnosis.""A more specific way to isolate cells is to use antibodies that latch on to distinctive molecules displayed on the surfaces of the target cells," she added. "However, this selective approach only works if the target cells come into contact with the antibodies designed to capture them. This is unlikely to happen when the cells are moving at relatively high speeds."
Enter Harvard-MIT Division of Health Sciences and Technology (HST) graduate student Sukant Mittal, MGH and HMS postdoctoral student Ian Wong, MIT chemical engineering professor William Deen, and MGH, HMS and HST Biomedical Engineering Professor Mehmet Toner. Together, the quartet have developed a new microfluidic device that they claim can target tumor cells, stem cells or other types of cells quicker than similar devices currently on the market. They discuss their research in Tuesday's edition of the Biophysical Journal.
Their device is designed in order to guide the fluid mixtures in order to make it easier to bring the target cells in contact with the antibodies that capture them. They designed it using a soft membrane with nanoscale pores which separate a pair of microchannels.
The fluids enter one microchannel, and in the midst of their journey through it, they and the targeted cells are guided towards the membrane dividing the two channels. There, the fluids are allowed to pass into the second microchannel, but the cells are unable to do so.
"Once they reach the surface, they start rolling – slowly enough that target cells have time to attach to the antibodies and get captured, but fast enough to keep the other cells moving. Such rolling behavior is similar to how white blood cells or stem cells selectively “home in” to sites of infection and injury in the body," Trafton wrote, adding that the technology "could be used in applications such as point-of-care diagnostics and personalized medicine."
One possible use for these devices, according to the MIT News report, is to isolate cancer cells from the rest of a patient's blood sample. The researchers have reportedly previously demonstrated that the amount of circulating tumor cells in a person's bloodstream corresponds with the clinical response to treatment in that patient, leading them to believe that there is potential in creating personalized treatment programs for those suffering from the disease.
Image Caption: This microfluidic device can rapidly isolate target cells using a nanoporous membrane sandwiched between two channels. Credit: Sukant Mittal and Ian Wong
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