A cure may not be around the corner, but scientists are hard at work on ways to replicate the functions of the pancreas. Researchers are using rodents to develop a system for targeted non-user initiated insulin delivery.
It turns out that attaching a programmable continuous glucose monitor to a pump isn’t the only way to develop a closed loop artificial pancreas system. Instead of using a mechanical device programmed with a set of algorithms to determine insulin delivery, a cohort of researchers at the North Carolina State University, the University of North Carolina at Chapel Hill, the Massachusetts Institute of Technology and the Children’s Hospital in Boston have developed an injectable nanoparticle network that releases insulin when it senses the presence of glucose.
Nanoparticles are ultra-small particles that are now being used as delivery systems for drugs when it is important that the drug precisely aim for a specific organ or tissue site. The particles are generally between 1 and 100 nanometers (an ant is approximately 5 million nanometers) and have many promising applications in biotechnology and engineering.
The closed loop system the researchers developed is like a network of connected onions each composed of a series of layers. At the center of each onion is a core of insulin surrounded by the enzyme glucose-oxidase.
Each nanoparticle’s surface is covered with a negatively or positively charged modified dextran molecule. The opposing charges between the individual nanoparticles form an electrostatic interaction which keeps the network together. Being porous, blood can freely travel through the network reaching the insulin core of the particles. When glucose levels are elevated, glucose oxidase converts glucose into gluconic acid. The acid eats away at the dextran outer layer and releases insulin into the circulation. In studies on mice, the network was able to keep the animals’ blood glucose in range for up to ten days with no unacceptable side effects.
How this technology would work in humans remains unknown but it does speak to the many possibilities there may be to approach the design of a replacement pancreas.