[Editors] On a 'roll': MIT devises new cell-sorting system

[Elizabeth Thomson]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

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On a 'roll': MIT researchers devise new cell-sorting system

--Process could yield low-cost tool for diagnosing cancer, other  
diseases
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For Immediate Release
FRIDAY, MAR. 7, 2008
Contact: Elizabeth A. Thomson, MIT News Office -- Phone: 617-258-5402  
-- Email: thomson at mit.edu

PHOTO AVAILABLE


CAMBRIDGE, Mass. - Capitalizing on a cell's ability to roll along a  
surface, MIT researchers have developed a simple, inexpensive system  
to sort different kinds of cells - a process that could result in low- 
cost tools to test for diseases such as cancer, even in remote  
locations.

Rohit Karnik, an MIT assistant professor of mechanical engineering  
and lead author of a paper on the new finding appearing this week in  
the journal Nano Letters, said the cell-sorting method was minimally  
invasive and highly innovative.

“It's a new discovery,” Karnik said.  “Nobody has ever done anything  
like this before.”

The method relies on the way cells sometimes interact with a surface  
(such as the wall of a blood vessel) by rolling along it. In the new  
device, a surface is coated with lines of a material that interacts  
with the cells, making it seem sticky to specific types of cells. The  
sticky lines are oriented diagonally to the flow of cell-containing  
fluid passing over the surface, so as certain kinds of cells respond  
to the coating they are nudged to one side, allowing them to be  
separated out.

Cancer cells, for example, can be separated from normal cells by this  
method, which could ultimately lead to a simple device for cancer  
screening. Stem cells also exhibit the same kind of selective  
response, so such devices could eventually be used in research labs  
to concentrate these cells for further study.

Normally, it takes an array of lab equipment and several separate  
steps to achieve this kind of separation of cells. This can make such  
methods impractical for widespread screening of blood samples in the  
field, especially in remote areas. “Our system is tailor-made for  
analysis of blood,” Karnik says. In addition, some kinds of cells,  
including stem cells, are very sensitive to external conditions, so  
this system could allow them to be concentrated with much less damage  
than with conventional multi-stage lab techniques.

“If you're out in the field and you want to diagnose something, you  
don't want to have to do several steps,” Karnik says. With the new  
system,  “you can sort cells in a very simple way, without processing.”

Now that the basic principle has been harnessed in the lab, Karnik  
estimates it may take up to two years to develop into a standard  
device that could be used for laboratory research purposes. Because  
of the need for extensive testing, development of a device for  
clinical use could take about five years, he estimates.

The work was a collaboration between Karnik and six other  
researchers: MIT Institute Professor Robert Langer, Jeffrey Karp of  
the Harvard-MIT Division of Health Sciences and Technology, Seungpyo  
Hong, Ying Mei and Huanan Zhang of MIT's Department of Chemical  
Engineering, and Daniel Anderson of the Center for Cancer Research.

The work was funded by a grant from the National Institutes of Health.

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Written by David Chandler, MIT News Office