【bio-news】MIT Device Draws Cells Close -- But Not Too Close -- Together

更多相关内容请访问"医药家园论坛"万人专家团为您在线答疑

MIT Deice Draws Cells Close -- But Not Too Close -- Together

03/29/07 -- In a popular children's game participants stand as close as possible without touching. But on a microscopic leel, coaxing cells to be ery, ery close without actually touching one another has been among the most frustrating challenges for cell biologists.

Now MIT researchers led by Sangeeta Bhatia, associate professor of electrical engineering and computer science at the Harard-MIT Diision of Health Sciences and Technology (HST) and Brigham and Women's Hospital, hae soled the problem with a noel deice. The work promises to allow researchers to perform cellular experiments that were preiously impossible.

Bhatia and HST postdoctoral associate Elliot Hui describe the deice in the March 27 online issue of the Proceedings of the National Academy of Sciences. Hui is first author of the paper.

The new deice, a microelectromechanical system (MEMS), allows biologists to physically arrange cells to be either touching, close but not touching, or completely separated from one another. Further, they can change that configuration at will. And the deice works without the use of tools such as the microscopes or robotic control arms typically required by MEMS deices.

Because cells communicate ia signals transmitted both through the touching of cell membranes and through soluble molecules that flow between separated cells, biologists need to ary the spacing of cells to study their interactions. Also, since some signals induce a cell to change its internal programming, it is important for biologists to be able to rearrange cells oer time to learn which signals spur change and which don't.

In the past, researchers erected chemical "moats" around cells in an attempt to keep them close but separate. Oer time, howeer, cells inariably breech the diide. "They are ery good at crossing the moat," said Bhatia, who performed seeral such experiments in graduate school.

Bhatia and Hui's first thoughts about how to sole this cellular space and time problem inoled another children's game: plastic puzzles with squares that slide around on a grid. They wondered if they could put different cells on each square and then moe them around.

This idea quickly eoled into an elegant tool designed expressly for biologists.

The deice inoles two separate comb-shaped pieces coated with liing cells. These two pieces can click into place at two settings: One allows cells on the edges of the combs to touch, the other maintains a gap of 80 micrometers, or about four cell widths. The assembly is geared so that switching between these two settings inoles a moement of two millimeters, an amount controllable by the human hand. Hui selected 80 micrometers as the gap setting because at shorter distances, cells sometimes migrate across the gap and end up touching. And at wider distances, some soluble signals drop off.

Bhatia and Hui hae used the new deice to study lier cells. The two found that to get lier cells to express specific lier functions, they needed to touch supporting stromal cells for 18 hours. For the lier cells to surie and continue to act as lier cells, they don't hae to keep touching these stromal cells, but they do need to stay close.

The finding will allow Bhatia and Hui to examine more deeply which surface molecules trigger lier cell differentiation and which soluble molecules maintain it.

Such information will help the team deise different approaches to engineering lier therapeutics by helping them understand exactly which signals are needed to support specific lier cell functions. Instead of building an entire lier from scratch, Bhatia wants to isolate the key cell type, "the business end of the organ," and get it to work without replicating the entire cellular enironment that supports it. "If you can get away with it, you want to get rid of the supporting cells," she says.

This simple deice will also be useful for exploring a host of other cellular interactions. Most prominently, the deice could be ery useful in exploring embryonic deelopment, during which the local cellular enironment dictates deelopment of major organs oer time, and cancer, in which supporting cells are thought to play a role in tumor formation.

Source: Massachusetts Institute of Technology

http://www.bio.com/newsfeatures/newsfeatures_research.jhtml?cid=27400028

本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。

本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。