Self-rolling sensors take heart cell readings in 3D

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26 Aug, 2019

Self-rolling sensors take heart cell readings in 3D

A new organ-on-an-electronic-chip platform, published in Science Advances, uses self-rolling biosensor arrays to coil up and measure the electrophysiology of heart cells in 3D.

Researchers from Carnegie Mellon University (CMU) and Nanyang Technological University, Singapore (NTU Singapore) have developed an organ-on-an-electronic-chip platform, which uses bioelectrical sensors to measure the electrophysiology of the heart cells in three dimensions. These 3D, self-rolling biosensor arrays coil up over heart cell spheroid tissues to form an “organ-on-e-chip,” thus enabling the researchers to study how cells communicate with each other in multicellular systems such as the heart.

3D cardiac spheroid labeled with Ca2+ indicator dye encapsulated by the self-rolling sensor array.

The organ-on-e-chip approach will help develop and assess the efficacy of drugs for disease treatment—perhaps even enabling researchers to screen for drugs and toxins directly on a human-like tissue, rather than testing on animal tissue. The platform will also be used to shed light on the connection between the heart’s electrical signals and disease, such as arrhythmias. The research, published in Science Advances, allows the researchers to investigate processes in cultured cells that currently are not accessible, such as tissue development and cell maturation.

“For decades, electrophysiology was done using cells and cultures on two-dimensional surfaces, such as culture dishes,” says Tzahi Cohen-Karni, an associate professor of biomedical engineering and materials science and engineering. “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.”

A spheroid encapsulated by 3D self-rolling biosensor arrays (top) and a spheroid that is not encapsulated (bottom). Imaged at (i) 0 hours (immediately after encapsulation), (ii) 1 hour, (iii) 2 hours, and (iv) 3 hours. Green, red, and blue denote live cells, dead cells, and cell nuclei, respectively.

The “organ-on-e-chip” platform starts out as a small, flat rectangle, not unlike a microscale slap bracelet. A slap bracelet starts out as a rigid, ruler-like structure, but when you release the tension it quickly coils up to band around the wrist.

Highly flexible 3D biosensor array unrolling with a glass capillary.

The organ-on-e-chip starts out similarly. The researchers pin an array of sensors made of either metallic electrodes or graphene sensors to the chip’s surface, then etch off a bottom layer of germanium, which is known as the “sacrificial layer.” Once this sacrificial layer is removed, the biosensor array is released from its hold and rolls up from the surface in a barrel-shaped structure.

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Emily graduated Magna Cum Laude from the University of Pittsburgh in 2015 with a double major in English Writing (Poetry) and Anthropology (Archaeology). While attending Pitt, she worked closely with science writer Hali Felt, was the editor-in-chief of the interdisciplinary research and literary jou...

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