Researchers have developed new injectable nanoparticles that may eliminate the need for patients with diabetes to constantly monitor their blood-sugar levels and inject themselves with insulin.
The nanoparticles were designed to sense glucose levels in the body and respond by secreting the appropriate amount of insulin, thereby replacing the function of pancreatic islet cells, which are destroyed in patients with Type 1 diabetes.
This type of system could ensure that blood-sugar levels remain balanced and improve patients' quality of life, according to the researchers.
"Insulin really works, but the problem is people don't always get the right amount of it. With this system of extended release, the amount of drug secreted is proportional to the needs of the body," said Daniel Anderson, associate professor of chemical engineering.
Currently, people with Type 1 diabetes typically prick their fingers several times a day to draw blood for testing their blood-sugar levels. When levels are high, these patients inject themselves with insulin, which breaks down the excess sugar.
The new system consists of an injectable gel-like structure with a texture similar to toothpaste, said Zhen Gu lead author of the paper.
The gel contains a mixture of oppositely charged nanoparticles that attract each other, keeping the gel intact and preventing the particles from drifting away once inside the body.
Using a modified polysaccharide known as dextran, the researchers designed the gel to be sensitive to acidity. Each nanoparticle contains spheres of dextran loaded with an enzyme that converts glucose into gluconic acid.
Glucose can diffuse freely through the gel, so when sugar levels are high, the enzyme produces large quantities of gluconic acid, making the local environment slightly more acidic.
That acidic environment causes the dextran spheres to disintegrate, releasing insulin. Insulin then performs its normal function.
Tests on mice with Type 1 diabetes showed that a single injection of the gel maintained normal blood-sugar levels for an average of 10 days.
Because the particles are mostly composed of polysaccharides, they are biocompatible and eventually degrade in the body.
