|A spongelike matrix carries a core of insulin and other drugs.--Courtesy of NC State|
To mimic the release of insulin by a healthy pancreas, researchers at the University of North Carolina have created a spongelike substance that surrounds an insulin core and releases the protein when triggered by a rise in blood sugar.
The material, made from chitosan, which is found in shrimp and crab shells, is a porous sphere that contains nanocapsules made of glucose oxidase or catalase enzyme polymers. The spongy matrix can be used to encapsulate insulin or, according the university, other drugs that require a similar form of delivery.
In the case of insulin, the glucose in the nanoparticles releases hydrogen ions when a diabetic patient's blood sugar rises. The ions bind to the chitosan material, giving it a positive charge, which causes them to push apart and allow the insulin to escape into the bloodstream. The entire capsule, only about 250 micrometers in diameter, can be injected into a patient and was effective in animal tests for up to 48 hours.
Lead researcher Zhen Gu and his team published a similar study in May using nanoparticles to release insulin for up to 10 days at a time. The new sponge technology, in a paper published in ACS Nano, has implications for further research, Gu said, and may also be used to carry cancer drugs.
"We wanted to mimic the function of healthy beta-cells, which produce insulin and control its release in a healthy body," Gu said in a statement. "But what we've found also holds promise for smart drug delivery targeting cancer or other diseases."
Special Report: The Future of Nanotech Delivery - 'Smart' insulin delivery