Insulin Injections Could be Replaced by Automatic Nanoparticle-Network
Scientists have developed a network of nanoscale particles with the ability to release insulin exactly when needed over a period of several days in a development that could radically simplify diabetes treatment. The sophisticated complex can be injected into the body were it simulates the natural function of reacting to rising blood-sugar levels, maintaining normal blood sugar levels for more than a week in animal-based laboratory tests. The work was done by researchers at North Carolina State University, the University of North Carolina at Chapel Hill, the Massachusetts Institute of Technology and Children's Hospital Boston.
"We've created a ‘smart' system that is injected into the body and responds to changes in blood sugar by releasing insulin, effectively controlling blood-sugar levels," says Dr. Zhen Gu, lead author of a paper. "We've tested the technology in mice, and one injection was able to maintain blood sugar levels in the normal range for up to 10 days."
The new, injectable nano-network is composed of a mixture containing nanoparticles with a solid core of insulin, modified dextran and glucose oxidase enzymes. When the enzymes are exposed to high glucose levels they effectively convert glucose into gluconic acid, which breaks down the modified dextran and releases the insulin. The insulin then brings the glucose levels under control. The gluconic acid and dextran are fully biocompatible and dissolve in the body.
Each of these nanoparticle cores is given either a positively charged or negatively charged biocompatible coating. The positively charged coatings are made of chitosan (a material normally found in shrimp shells), while the negatively charged coatings are made of alginate (a material normally found in seaweed).
When the solution of coated nanoparticles is mixed together, the positively and negatively charged coatings are attracted to each other to form a "nano-network." Once injected into the subcutaneous layer of the skin, the nano-network holds the nanoparticles together and prevents them from dispersing throughout the body. Both the nano-network and the coatings are porous, allowing blood - and blood sugar - to reach the nanoparticle cores.
"This technology effectively creates a ‘closed-loop' system that mimics the activity of the pancreas in a healthy person, releasing insulin in response to glucose level changes," Gu says. "This has the potential to improve the health and quality of life of diabetes patients."
Gu's research team is currently in discussions to move the technology into clinical trials for use in humans.
"Injectable Nano-Network for Glucose-Mediated Insulin Delivery", by Zhen Gu, North Carolina State University and the University of North Carolina at Chapel Hill; Alex Aimetti, Yunlong Zhang, Omid Veiseh, Robert Langer and Daniel G. Anderson, MIT and Children's Hospital Boston; Qun Wang, Tram T. Dang and Hao Cheng, MIT.
Published in ACS Nano on May 2