Feb 20 2018
In order to create a power source for advanced implantable technologies, a research team led by Michael Mayer from the University of Fribourg, together with researchers from the University of Michigan and UC San Diego, created an electric eel-inspired device that generated 110 volts from gels filled with water, known as hydrogels. Their results exhibit potential for a soft power source to rely on a biological system's chemical energy.
Electric Eel-Inspired Device Reaches 110 Volts: This photo depicts the printed, high voltage implementation of the artificial electric organ. A 3D bioprinter was used to deposit arrays of gel precursor droplets onto plastic substrates, which were then cured with a UV light to convert them into solid gels. Alternating high-salinity and low-salinity gels (red and blue gels, respectively) were printed onto one substrate, and alternating cation-selective and anion-selective gels (green and yellow gels, respectively) were printed onto a second substrate. When overlaid, these gels connect to form a conductive pathway of 612 tetrameric gel cells that can be used to generate up to 110 volts. (Image credit: Anirvan Guha and Thomas Schroeder)
Anirvan Guha, a graduate student at the University of Fribourg's Adolphe Merkle Institute, will present the paper at the 62nd Biophysical Society Annual Meeting, held February 17-21, in San Francisco, California. Guha and his colleagues drew inspiration from the electric eel's ability to generate hundreds of volts and stacked hydrogels full of different strengths of salt water.
Ions are charged molecules or atoms and when ions collect on either side of a cell membrane, they form an ion gradient. The researchers harnessed energy from the electric potential, or voltage, across the ion gradients. As additional hydrogels were stacked on top of each other, the voltage increased further. The researchers were able to generate up to 110 volts.
To stack the numerous individual hydrogels needed to produce over 100 volts, the researchers used a printer that "deposits little droplets of gel ... with the precision and spatial resolution to print an array of almost 2,500 gels on a sheet the size of a normal piece of printer paper," Guha said.
The team's following goal is to increase the current traveling through the hydrogel. "Right now, we're in the range of tens to hundreds of microamperes [the basic unit for measuring an electrical current], which is too low to power most electronic devices," Guha said.
In the future, the research team expects their results will help create power sources for implantable devices that can "utilize the [ion] gradients that already exist within the human body," Guha said. "Then you may be able to create a battery which continuously recharges itself because these ionic gradients are constantly being re-established within the body."