Patch with beta cells
For many decades, researchers have been trying to reproduce the functions of pancreatic beta cells that are disrupted in diabetes mellitus. In healthy people, these cells synthesize, accumulate and release the hormone insulin, which is necessary for the utilization of glucose, the content of which in the bloodstream increases after eating. However, in patients with diabetes mellitus, these cells are either damaged or lose the ability to produce enough insulin to maintain normal blood glucose levels.
Insulin injections are a painful and often imperfect alternative, and transplantation of donor beta cells is associated with a high risk of rejection and the development of side effects of taking immunosuppressive drugs.
Scientists from the University of North Carolina at Chapel Hill and North Carolina State University, working under the guidance of Dr. Zhen Gu, have proposed a new solution to the problem: a synthetic patch filled with beta cells capable of synthesizing insulin doses, if necessary, to normalize blood glucose without the risk of hypoglycemia.
As a basis for the new patch, the authors took the innovative technology "smart insulin patch", described in one of last year's issues of Proceedings of the National Academy of Sciences. Both versions of the patch are thin squares of biocompatible polymer material the size of a 25-cent coin, covered with tiny needles. However, whereas in the earlier version these needles are filled with insulin-containing bubbles, the needles of the new "smart patch" are populated with living beta cells.
The smallest needles of the new patch are filled with a nutrient medium in which thousands of beta cells are immersed, encapsulated in alginate, a biocompatible polysaccharide isolated from algae. When applying the patch to the skin, the microneedles penetrate into the capillaries, providing contact between the internal environment and the cells inside the patch.
The needles also contain "glucose signal amplifiers" – synthetic nanobubbles filled with three chemical compounds that ensure the ability of beta cells to register an increase in blood glucose and react accordingly.
An image of a "smart patch" covered with microneedles.
Experiments on a mouse model of type 1 diabetes mellitus demonstrated the ability of the new patch to quickly respond to a rapid increase in blood glucose levels and reduce it to normal values for a period of up to 10 hours.
In order to test the patch's ability to regulate glucose levels without developing hypoglycemia, the researchers applied a second patch to the animal's skin, which, as they hoped, did not lead to the release of excess insulin and the development of hypoglycemia. Instead, the second patch extended the period of effective regulation of glucose levels to 20 hours.
In order to introduce the new development into clinical practice, further improvements are needed, as well as conducting preclinical and clinical studies. However, to date, the authors believe that the results they have obtained are proof of the viability of an experimental approach that can become a safer and easier-to-use alternative to existing methods of hormone replacement therapy for diabetes mellitus.
Article by Yanqi Ye et al. Microneedles Integrated with Pancreatic Cells and Synthetic Glucose-Signal Amplifiers for Smart Insulin Delivery is published in the journal Advanced Materials.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of North Carolina Health Care: Scientists create a painful patch of insulin-producing beta cells to control diabetes.
16.03.2016