Diabetes: Synthetic beta cells could lead to skin patch treatment

A team of scientists has created synthetic pancreatic beta cells that automatically release insulin when they sense high blood sugar.

 In the journal Nature Chemical Biology, researchers from the University of North Carolina at Chapel Hill and North Carolina State University in Raleigh describe how they developed and tested the synthetic cells.

Senior author Zhen Gu, a professor in biomedical engineering at both universities, and team hope that one day, the cells could be used in a noninvasive skin patch to treat diabetes.

They found that just one injection of the synthetic beta cells kept blood sugar in diabetic mice at normal levels for 5 days.

Diabetes is a disease that develops when the body has problems with using or producing insulin, a hormone that helps cells to take in and convert blood sugar, or glucose, into energy.
The body produces insulin in the pancreas, which is a glandular organ behind the stomach that houses the beta cells that make and release the right amount of the hormone, depending on glucose levels.

Need for noninvasive insulin delivery

Around 6 million of the 30 million people in the United States with diabetes manage the disease using insulin treatments, either by regular injections or with infusion pumps.
Over the years, there have been attempts to develop a pill form of insulin treatment, but they have encountered problems — including the fact that the body's strong digestive system breaks down the large molecules in the pill before they make it to the bloodstream.

It is also possible to treat some cases of diabetes with transplanted pancreatic cells. However, these treatments are costly, need drugs that suppress immune reactions to the transplant, and rely on donated tissue, which is scarce. There is also a high risk that the transplanted cells will perish anyway.

In their study paper, the scientists explain that biological engineers have made several attempts to "recreate the key functions" of pancreatic beta cells for therapeutic purposes. They give examples, such as nano particles cloaked in cell membranes and microgels that slowly release drugs.

Synthetic cells need to be smarter

But a common problem with previous approaches to mimic beta cells is their "single-compartment" structure and their "relatively passive" way of interacting with the biology of the body, note the authors.

Some researchers have tried to create multi-compartment structures to mimic beta cells — for instance, to deliver a mixture of drugs or produce a cascading effect.

But none so far have managed to "mimic the higher-order functions" of the natural beta cells whose sophisticated systems "can precisely sense the external environment, make internal decisions, and trigger feedback."

The new study marks nearly a decade of work in which Prof. Gu and his team have been wrestling with this problem. The result is a synthetic beta cell that very closely mimics the key processes of natural pancreatic beta cells.