By using larger spherical components, Massachusetts Institute of Technology researchers have found a way to reduce the immune system from rejecting biomedical implant devices. The bigger spheres are better able to maintain their function and avoid scar-tissue buildup.
The researchers tested spheres in two sizes — 0.5 and 1.5 millimeters in diameter. The implanted cells could replace patients’ pancreatic islet cells, which are nonfunctional in Type I diabetes.
In tests of diabetic mice, the spheres were implanted within the abdominal cavity, and the researchers tracked their ability to accurately respond to changes in glucose levels. The devices prepared with the smaller spheres were completely surrounded by scar tissue and failed after about a month. The larger ones were not rejected and continued to function for more than six months.
The larger spheres also evaded the immune response in tests in nonhuman primates. Smaller spheres implanted under the skin were engulfed by scar tissue after only two weeks, while the larger ones remained clear for up to four weeks.
The MIT team hopes to use the insight to further develop an implantable device that could mimic the function of the pancreas, potentially offering a long-term treatment for diabetes patients.
