Electrical Pulses Teach Lab-Grown Pancreatic Cells to Act Like the Real Thing

Growing insulin-producing cells in a laboratory dish is technically straightforward. Growing them well enough to function like the cells destroyed by Type 1 diabetes is another matter entirely. Lab-grown pancreatic islet cells derived from stem cells often fail to complete their maturation - they develop the right shape and gene expression patterns, but they do not release insulin reliably in response to blood sugar changes the way natural islet cells do.

A collaboration between the Perelman School of Medicine at the University of Pennsylvania and the School of Engineering and Applied Sciences at Harvard University has now found a way to bridge that gap. By embedding an ultrathin mesh of conductive wires into growing pancreatic organoids and delivering a controlled 24-hour electrical rhythm, the researchers prompted the cells to mature fully and coordinate their hormone secretion. The results, published in Science, suggest a potential route toward transplantable pancreatic tissue that does not require donors or permanent immunosuppression.

The Maturation Problem

In Type 1 diabetes, the immune system destroys clusters of hormone-secreting cells called islets, eliminating the body's ability to regulate blood sugar. The U.S. Centers for Disease Control estimated that approximately two million Americans of all ages had Type 1 diabetes as of 2021. In the most severe cases, the only lasting treatment is a transplant - either a full pancreas, part of one, or isolated islet cells.

Transplants are severely limited by donor availability. Patients often wait a year or more, and after receiving a transplant they must take immunosuppressant drugs for the rest of their lives. Lab-grown islet cells from stem cells would circumvent both problems - if only they would mature properly. Clinical trials testing stem cell-derived islet transplants are already underway, but the maturation gap remains a critical obstacle.

"I like to call it when cells get their PhDs," said Juan Alvarez, PhD, assistant professor of Cell and Developmental Biology at Penn, who led the project with Jia Liu of Harvard. "It is when cells stop being undecided undergrads, and commit to their career path of being pancreatic or islet cells."

The Cyborg Organoid

The approach involves placing a stretchable mesh - thinner than a single human hair - between layers of developing pancreatic cells. The cells then cluster around the mesh, forming islets with the electronic lattice woven through them. This hybrid of biological tissue and electronic device gave rise to the "cyborg organoid" description.

The mesh serves two roles simultaneously. It records the electrical activity of individual islet cells over time - something not previously possible in three-dimensional tissue - and it delivers controlled electrical signals back to the cells.

Using recordings from the mesh, the team found that immature islet cells lack coordinated electrical activity. They do not work together. After exposing the organoids to a controlled 24-hour electrical rhythm - mirroring the body's natural circadian cycle - the cells began firing in synchrony. After just four days of this induced rhythm, the cells continued cycling on their own, as though the external signal had reset an internal clock.

The electrical data showed that not only did individual cells change their behavior, but they began acting as a coordinated ensemble rather than independent units. Hormone secretion followed: the mature cells released insulin and glucagon at the appropriate times and in appropriate quantities in response to glucose.

Two Paths to Transplantation

Alvarez described two possible clinical applications. In the first, lab-grown islet cells could be electrically "primed" before transplantation, then implanted without the mesh and left to function independently. In the second, the mesh stays in place after transplantation, monitoring the cells continuously and delivering corrective stimulation if they begin to lose function - a response that can occur under physiological stress or disease.

That second possibility points toward AI-driven management. "In the future, we could have a system that runs without human intervention," Alvarez said, describing a closed-loop system that monitors islet cell electrical activity and delivers stimulation autonomously.

The comparison to pacemakers and deep brain stimulation is direct. Those devices use electrical signals to regulate heart rhythm and neurological function respectively. A pancreatic version would apply the same principle to metabolic regulation.

What Remains to Be Demonstrated

The current work establishes feasibility in organoids - three-dimensional clusters of cells grown outside the body. Organoids are powerful research tools, but they do not fully replicate the vascular supply, immune environment, or mechanical conditions of a living organ. Whether electrically matured islet cells survive transplantation, integrate with host tissue, and maintain function over months or years in a living body has not yet been demonstrated.

The researchers also have not yet shown that the electronic mesh is biocompatible over long periods in vivo, or that the immune system would tolerate it as an implant. These are standard questions for any tissue-electronics hybrid device entering preclinical development.

The work was supported by the NIH, Breakthrough T1D, the JDRF, the JPB Foundation, and the Diabetes Research Center at the University of Pennsylvania.