Because muscle sells can stretch themselves many times their own length, scientists have been looking for a platform with which to study them under motion. Now a collaboration of researchers from Purdue and Stanford universities has developed stretchable electrode arrays to do the job.
MIT Tech Review explains:
The new system, developed by a team led by Babak Ziaie, a professor of electrical and computer engineering at Purdue, consists of a stretchy polymer containing a small array of gold-coated pins. These pins act as microelectrodes that can send and record electrical signals. In the past, the difficulty in designing these electrode arrays has been developing electrical connections for the electrodes that can be stretched without degrading their performance. In the Purdue system, electrical current is carried to and from the electrodes by a liquid metal alloy that flows through channels within the polymer.
The stretchy electrode arrays maintain their electrical properties better than any flexible electrode previously developed. Using a liquid alloy means that resistance to electrical current does not drop when the array is stretched.
This makes them a useful tool for studying and stimulating cardiac cells, says Rebecca Taylor, one of the Stanford researchers working on the project. The heart’s muscle cells receive regular electrical stimulation that causes them to beat. They also experience regular mechanical stresses caused by the beating of the tissue around them. These stimuli tell heart cells to keep acting like heart cells, so mimicking them in the lab is an important first step toward engineering tissue to repair the damage caused by heart attacks or congenital heart defects.
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Image: This system, made of a stretchy polymer embedded with four microelectrodes, can be stretched by a micromanipulator (the black clamp) to mimic the electrical and mechanical activity of the heart. Credit: Babak Ziaie