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Engineering the cell: Mechanical engineering goes biological

The Department of Mechanical Engineering (ME), long the cradle of the automotive industry's leading engineers, is joining the life sciences revolution in a big way.

Nearly half of its 54 faculty members have a significant interest in biological systems, and two of the newest hires, associate Prof. Edgar Meyhöfer and assistant Prof. Robert Dennis, are leading the charge in something they call "bio-systems."

This term generally refers to a broad area of lifefrom the molecular and cellular level to that of tissues and organismsthat are either inherently mechanical in nature, or that may be addressed by classical mechanical engineering disciplines, such as thermal and fluid sciences, dynamics, and controls or materials.

"Look at a cell," Meyhöfer says. "It's actually a very complex nano-machine. It has about 10,000 different proteins, its size is of a few micrometers, yet it's capable of organizing all reactions, and having everything happen at the same time. In a way, it's the ideal study system for learning how we as engineers can develop nano-technology. It's at least one example of a perfect solution."

The crux of Dennis' research concerns tissue engineering of skeletal and cardiac muscle. "I work on self-organizing skeletal and cardiac muscle tissue in culture," he says. "I start with cells, and I give them mechanical and chemical signals to encourage or promote them to form into functional muscle organs, such as a little functional piece of a heart muscle or a skeletal muscle." The end result is a tiny muscle grown in a petri dish that contracts on command.

ME has hired several faculty members to do this kind of work at all structural levels, Dennis says. "Edgar (Meyhöfer) does this with molecules that are from living organisms; I do it with cells and tissues; others, such as Art Kuo and James Ashton-Miller, do it with whole organisms," Dennis says. Kuo is an associate professor in the departments of Mechanical Engineering and Biomedical Engineering, and a faculty associate, Institute of Gerontology. Ashton-Miller is a distinguished senior research scientist in the departments of Mechanical Engineering and Biomedical Engineering, senior research scientist at the Institute of Gerontology, and director of the Biomechanics Research Laboratories.

"Art and James don't actually engineer the organism, but they measure the dynamics. Edgar tears apart cells and investigates single molecules," he says. "My objective is to actually start with living cells and build them up into functional tissues. So the spectrum goes from molecules all the way up into living organisms."

Dennis and Meyhöfer recently received almost $6 million in research
funding from the Defense Advanced Research & Projects Agency (DARPA), which conducts advanced research for the Department of Defense. They are working on creating "living-based actuators"Meyhöfer at the molecular level, Dennis at the cellular level. The practical applications might include "the building of micro-chemical sorters, chemical weapons detectors, micro-actuators that might be used to restore function if someone is injured," says Dennis, who is also an assistant professor in Biomedical Engineering and an assistant research scientist at the Institute of Gerontology.

Dennis is a practitioner of a field he calls "biomechatronics"the integration of biology, mechanics and electronics to possibly meld biological organs with electromechanical devices and systems.

Meyhöfer, who mostly taught medical students during his tenure in the department for Molecular and Cellular Physiology at a medical school in Hannover, Germany, received his Ph.D. in zoology at the University of Washington, and did post-doctoral work in biophysics in Seattle. Meyhöfer's major research interests are in molecular motors, which he describes as "little machines in our bodies that use chemical energy from the cell to drive all kinds of mechanical processes as diverse as muscular contraction, the beating of our hearts, cell division or intracellular transport."

One of Meyhöfer's new research projects with faculty from ME, biomedical and electrical engineering, aims at taking the motors studied at the single molecule level and integrating them into man-made micro- and nano-sized artificial structures.

"Anything that can't be done by diffusion, which basically only works efficiently over a micrometer distance or soor anything where you need some asymmetric distribution of things, where you need to get something to a specific locationneeds to be done by the cell expending energy; by having the molecular machinery actually transport things around," Meyhöfer says.

Using precision instruments to measure these machines, many new things can be discovered, including what steps the molecule takes, how much force it generatesand how oftenand how it interacts with the tract along which it moves. Then, says Meyhöfer, "we can go in and use modern genetic engineering techniques to change the molecules."

This is an abridged version of an article originally written by Randy Milgrom for the Department of Mechanical Engineering 2001­02 Annual Report.



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