A bed of microneedles: Johns Hopkins scientists' gadget measures muscle ...( Using the same technology that creates ...)

Each needle tip in the gadget, whose development and testing is reported this week in the advance online edition of the Proceedings of the National Academy of Sciences, can be painted with proteins cells tend to grab onto. By measuring how far a contracting muscle cell moves each needle, the scientists can calculate the force generated by the cell.

"What we have is a tool to measure and manipulate mechanical interactions between a single cell and its physical and biochemical surroundings," says Christopher Chen, Ph.D., associate professor of biomedical engineering at Johns Hopkins. "Cellular mechanics is really important to many normal and pathologic processes in people, and there's a lot we don't understand, even with available technology."

Because smooth muscle cells control the expansion and contraction of airways and blood vessels, the microneedle bed's ability to measure how a cell's environment affects the strength, duration and timing of cellular contractions should one day help shed light on medical conditions like asthma and high blood pressure, the researchers say.

The new device complements an ever-growing array of techniques to measure forces exerted by a contracting cell and overcomes some of their limitations, the researchers say. For example, one common method examines a cell lying on a thin sheet of material, which wrinkles when the cell contracts.

"This is like a person lying on a bed sheet and scrunching up part of the sheet," says first author John Tan, a graduate student in biomedical engineering. "Wrinkles appear all over the place, and it can be hard to figure out where the initial force was applied."

To overcome that complexity, scientists hav
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Contact: Joanna Downer
jdowner1@jhmi.edu
410-614-5105
Johns Hopkins Medical Institutions
27-Jan-2003