Sensors take 3D heart cell readings

Credit: Rebecca Enright/Art Editor Credit: Rebecca Enright/Art Editor

Researchers from Carnegie Mellon University and Nanyang Technological University in Singapore (NTU Singapore) have collaborated on a revolutionary “organ-on-an-electronic-chip platform.”

An organ-on-an-electronic-chip is a synthetic cell culture chip into which living human cells are placed to simulate how an organ acts in response to numerous situations. In this project, researchers from Carnegie Mellon and NTU Singapore created an organ-on-an-electronic-chip platform which contains bioelectrical sensors measuring the cardiac electrophysiology of heart cells in three dimensions.

Cardiac electrophysiology concerns the electrical activity of the cardiac system. The new biosensor arrays created by these researchers surround heart cell spheroid tissues, permitting researchers to observe the intercommunication of cells in the cardiac system and similar multicellular systems.

This organ-on-an-electronic-chip platform has a multitude of uses, including testing the effectiveness of drugs on human-like tissue rather than animal tissue (which is the current practice). Scientists will be able to more accurately predict the impact of drugs and toxins on human tissue. Another application is to study the interconnectivity between the heart’s electrical signals and various heart diseases. Finally, the platform enables future research in areas such as tissue development and cell maturation.

Tzahi Cohen-Karni, an associate professor of materials science and biomedical engineering, reports in an engineering press release, “For decades, electrophysiology was done using cells and cultures on two-dimensional surfaces, such as culture dishes. We are trying to circumvent the challenge of reading the heart's electrical patterns in 3D by developing a way to shrink-wrap sensors around heart cells and extracting electrophysiological information from this tissue."

Researchers like Cohen-Karni set up organ-on-an-electronic-chip platforms by first attaching a set of sensors to the chip’s surface. These sensors are typically composed of graphene sensors or metallic electrodes. The germanium composing the bottom layer of this set of sensors is removed, after which the set of sensors is free to move independently, and rolls around the surface of the chip.

Cardiac spheroids, long organoids containing heart cells and as wide as two or three human hairs, were the test surface upon which the researchers deployed their platform. The platform coils on its own over the spheroid, allowing the collection of precise and accurate electrical signal readings from the spheroids.

"Essentially, we have created 3D self-rolling biosensor arrays for exploring the electrophysiology of induced pluripotent stem cell-derived cardiomyocytes,” said Ph.D. student in biomedical engineering and lead author Anna Kalmykov. "This platform could be used to do research into cardiac tissue regeneration and maturation that potentially can be used to treat damaged tissue after a heart attack, for example, or developing new drugs to treat disease.”