"Movement of cells and cellular components on their own is a hallmark of all living systems. "

Light triggers flowers to open; subtle biochemical cues trigger mass movement of microbes towards the source of food, immune cells towards a wound, and stem cells towards the site of injury; and chemical energy fuels molecular motors that rearrange chromosomes during cell division. All these vital processes occur without wires or batteries. Researchers look to such biological processes to inspire development of improved biomedical tools. Such is the case of one researcher at Johns Hopkins who has succeeded in developing a microgripper that requires no source of electricity to perform its function.

To date, engineers have been largely unsuccessful in designing machines that operate in response to chemical cues – that is, until David H. Gracias, Associate Professor of Chemical and Biomolecular Engineering at The Johns Hopkins University, devised a microscopic-sized tool that opens and closes in response to chemicals. The microgripper does not require batteries or any other electrical power source.

The idea of using chemistry to generate motion for use in surgical applications is decidedly novel. “It is hard to make something autonomous if you need batteries. You have to recharge the batteries, and making small batteries is very difficult. It can also increase the cost a lot,” explains Gracias. Other surgical microtools cannot be used in hard-to-reach places in the body because they are wired. During laboratory tests, Gracias' wireless microgripper easily maneuvered through coiled tubes.

The microgripper is strong yet gentle. During tests, the device efficiently grasped and carried clusters of living cells without damaging them – cells continued to grow after they were released from the gripper. The microgripper can be fitted with sharp tips for cutting through connective tissue and pulling out cells. “This small device, without any electricity, was strong enough to cut out a chunk of cells from a piece of bladder, a tough tissue,” indicates Gracias.

For the full story, please go to:
http://www.nibib.nih.gov/HealthEdu/eAdvances/30Nov09


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