Transistor Chip for Continuous Monitoring of 3D Cell Cultures

A team led by researchers at the University of Cambridge has developed a 3D “organ-on-a-chip” with a difference – the cells in the device grow within an electrode that allows for continuous electrical monitoring.

The researchers have dubbed the device a transistor in a tube, or “Tubistor,” and hope that it can advance knowledge about a variety of diseases, potentially leading to new treatments.

Organ-on-a-chip devices are becoming increasingly popular as an alternative to laboratory animal models of disease, and allow researchers to model a variety of organs, specific diseases, and test new treatments. However, these devices often employ 2D cell cultures, which are limited in how closely they approximate real tissues.

“Two-dimensional cell models have served the scientific community well, but we now need to move to three-dimensional cell models in order to develop the next generation of therapies,” said Dr. Róisín Owens, a researcher involved in the study. “Three-dimensional cell cultures can help us identify new treatments and know which ones to avoid, if we can accurately monitor them,” said Dr. Charalampos Pitsalidis, the first author on the study.

One way to monitor cell cultures in real time is to attach electrodes to them that measure electrical activity. “The majority of the cells in our body communicate with each other by electrical signals, so in order to monitor cell cultures in the lab, we need to attach electrodes to them,” said Owens. “However, electrodes are pretty clunky and difficult to attach to cell cultures, so we decided to turn the whole thing on its head and put the cells inside the electrode.”

The team used a spongy polymer as a scaffold on which to grow cells. However, the polymer material is electrically conductive, and provides an alternative to traditional rigid metal electrodes. By housing the scaffold in a plastic tube, the researchers formed a “transistor” that can rapidly relay information on the electrical properties of cells grown in it. The tube also allows nutrients to flow through it, which help the cells to grow.

As the device doesn’t need to be dismantled to provide results, the researchers are able to conduct long-term experiments. “With this system, we can monitor the growth of the tissue, and its health in response to external drugs or toxins,” said Pitsalidis. “Apart from toxicology testing, we can also induce a particular disease in the tissue, and study the key mechanisms involved in that disease or discover the right treatments.”

The researchers are in the process of establishing a “brain on a chip” and a “gut on a chip” in the device, which they intend to connect to study the link between the microbiome and brain activity.