Research team develops biotransistors able to hear small beats of life

By December 23, 2019January 9th, 2020IBEC

Researchers at the Institute for Bioengineering of Catalonia (IBEC), a BIST centre, and at ICMAB have developed a flexible, cheap, and biocompatible transistor platform able to record an electrocardiogram of cells and micro-tissues during long periods of time.

The platform, based on organic transistor technology (EGOFET), can also measure the effect of drugs on beating cells, as cardiomyocytes, opening the door to several applications such as implantable devices for health.

One of the tests that almost every patient must face before a surgery or other health intervention is an electrocardiogram. To perform this screening, medical doctors traditionally use a set of electrodes, which are able to record the electrical activity of the heart. The question is: what happens when the signal is much smaller, for instance, when you want to hear the beat of small clusters of cells or groups of cells within tissues?

Scientists have been addressing this issue for years, since solving this drawback may pave the way for drug development and screening. Of equal importance, the development of these techniques together with the use of pluripotent stem cell derivatives opens the door not only to immediate applications in the cardiac field, but in other important areas of research, such as the neural field as well.

Now, experts at the Institute for Bioengineering of Catalonia (IBEC), in collaboration with the Institute of Materials Science of Barcelona (ICMAB-CSIC), have achieved a new milestone. By developing a bio-platform that integrates an organic electronic device called an Electrolyte Gated Organic Field Effect Transistor (EGOFETs) in its core, researchers have been able to monitor the electrical signal of cells and micro-tissues during long periods of time. The work is the result of a fruitful multidisciplinary collaboration between an organic electronic devices team (led by Dr. Marta Mas-Torrent from ICMAB), a bioengineering team (led by UB Professor Gabriel Gomila at IBEC) and a stem-cell tissue engineering team (led by ICREA Research Professor Núria Montserrat at IBEC), along with an instrumentation development collaboration with Dr. Tobias Cramer of the University of Bologna in Italy.

“It was amazing to see how the electrophysiological platform developed with seeded cardiac cells was functional for several weeks without degrading its performance. This capability opens endless applications in biology and biomedicine.” Said Dr. Adrica Kyndiah, first author of the paper and researcher at IBEC.

Printed and flexible transistors were fabricated by Dr. Marta Mas-Torrent’s group at ICMAB-CSIC. Then the surface of the EGOFET, and the full platform, was adapted to interface the cardiac cell clusters derived from human pluripotent stem cells for long time periods (several weeks). According to the authors of the paper published in the Biosensors and Bioelectronics Journal, the main advantage of using such EGOFETs for bioelectronics recording is three-fold:

First of all, EGOFETs are made of an organic material on a mechanically flexible substrate, they are biocompatible in nature, and they show a robust performance when operated in physiological environment. Secondly, a transistor offers intrinsic signal amplification without the use of external amplifiers as compared to conventional electrodes thus resulting in high signal to noise ratio. And third, it operates at low voltages preventing cell damage or unintentional cell excitation.

Researchers at IBEC not only tested the device on cardiac cells and cardiac micro-tissues, but also investigated the effect of two well known drugs affecting cardiac performance. Thus, screening of new compounds in cardiomyocytes and other pluripotent stem-cell derived electrical cells (such as neurons) would now be possible. This advance in turn would result in the reduction of animal models for these applications.

According to the multidisciplinary team, the results are a proof of concept, which could be extended from in vitro studis towards in vivo recordings of organs and tissues and to implantable devices to monitor health.

More information can be found on the IBEC website.