"Controlling tissue response is particularly important for implants, which tend to work for a while, then lose electrical sensitivity," said Bruce Wheeler, a UI professor of electrical and computer engineering and a researcher at the universitys Beckman Institute for Advanced Science and Technology. "If we can better understand and control the interface between electronic components and nerve cells, we could build more sophisticated and longer-lasting implants."
Wheelers microstamping technique uses lithographic methods, borrowed from the microelectronics industry, to precisely reproduce a master pattern with biologically relevant materials. "The microstamp works the same as a conventional rubber stamp except that the ink is polylysine (an artificial polymer commonly used for cell culture) and the patterns produced are measured in micrometers, or the same size as the cells themselves," Wheeler said.
To culture nerve cells in a dish, Wheeler works with graduate students John Chang and Johnny Nam, as well as colleague Gregory Brewer, a professor of medical microbiology at the Southern Illinois University School of Medicine in Springfield, who first removes brain cells from developing rat embryos. The cells are chemically and mechanically separated, then poured onto the patterned polylysine where they selectively attach to the surface.
"Within a few days, the cells send out processes that explore the environment, preferring areas that have intact polylysine," Wheeler said. "The cells soon mature and begin sending electrical signals."
Microlithographic techniques also can be
Contact: James E. Kloeppel
University of Illinois at Urbana-Champaign