'Lab on a Chip' technology emulates brain chemistry

Washington, Feb 13 : Researchers at Johns Hopkins from the Whiting School of Engineering and the School of Medicine have developed a micro-scale tool, a 'lab on a chip', that imitates brain chemistry.

This technology developed by a team of researchers led by Andre Levchenko, Ph.D., associate professor of biomedical engineering at the Johns Hopkins Whiting School of Engineering and faculty affiliate of the Institute for NanoBioTechnology, would help scientists better understand the working of nerve cells in the brain to form the nervous system.

"The chip we've developed will make experiments on nerve cells more simple to conduct and to control," said Levchenko.

It is possible for the nerve cells to decide which direction to grow by being sensitive to both the chemical cues flowing through their environment as well as those attached to the surfaces that surround them.

Similarly the chip, designed of a plastic-like substance and covered with a glass lid, features a system of channels and wells enabling researchers to control the flow of specific chemical cocktails around single nerve cells.

"It is difficult to establish ideal experimental conditions to study how neurons react to growth signals because so much is happening at once that sorting out nerve cell connections is hard, but the chip, designed by experts in both brain chemistry and engineering, offers a sophisticated way to sort things out," said Guo-li Ming, M.D., Ph.D., associate professor of neurology at the Johns Hopkins School of Medicine and Institute for Cell Engineering.

The researchers, during their experiments with the chip, had put single nerve cells, or neurons, onto the chip introducing specific growth signals (in the form of chemicals).

It was found that the growing neurons turned and grew toward higher concentrations of certain chemical cues attached to the chip's surfaces, as well as to signaling molecules free-flowing in solution.

When the neurons were subjected to conflicting signals (both surface bound and cues in solution), it was discovered that the cells turned randomly, indicating that the cells do not choose one signal over the other.

According to Levchenko, this holds the prevailing theory that it is possible for one cue to trigger different responses depending on a cell's surroundings.

"The ability to combine several different stimuli in the chip resembles a more realistic environment that nerve cells will encounter in the living animal," said Ming.

This in turn will make future studies on the role of neuronal cells in development and regeneration more accurate and complete.

A report on the work will be appearing in the recent issue of the British journal Lab on a Chip.

ANI