Polymer vesicle regulates glucose levels in mice without added insulin

Chinese researchers hope that their new polymersome—a polymer vesicle—has the potential to regulate glucose levels in diabetes without insulin. Yufen Xiao, Hui Sun, and Jianzhong Du of Tongji University make their polymersomes of a sugar-containing copolymer with a poly(ethylene oxide) tail (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.7b03219). Sugar side chains in the copolymer interact with the sugar-binding protein concanavalin A, which is then immobilized inside the vesicle by cross-linking. The polymersome soaks up glucose when the surrounding concentration is high and releases it when the concentration is low because concanavalin A has a higher affinity for free glucose than for the sugar side chain attached to the vesicle. The researchers tested this glucose sponge in mice with chemically induced elevated blood glucose levels. The blood glucose level of these mice dropped and stayed at normal levels for at least 36 hours after injection of the vesicles. “As a concept this is rather clever, and the demonstration in mice looks promising,” says Cameron Alexander, an expert on polymer therapeutics at the University of Nottingham. “The caveat is that these are complex systems, and a lot of development and tolerability studies will be needed before these are anywhere close to being used in humans.”