Implantable medical devices that intimately interact with the human body are often subject to the immune system’s foreign body response (FBR). This creates scarring around the implants, reducing their functionality over time. Now, scientists at MIT have developed a way to embed crystallized immunosuppressant drugs into implantable devices so that there is no serious localized immune reaction.
“We developed a crystallized drug formulation that can target the key players involved in the implant rejection, suppressing them locally and allowing the device to function for more than a year,” said Shady Farah, an MIT and Boston Children’s Hospital postdoc and co-first author of the study appearing in Nature Materials.
As a proof-of-concept, the team used their drug crystals to protect encapsulated islet cells that are being researched as a treatment option for type 1 diabetes. These were implanted in rodents and monkeys and survived for at least 1.3 years and six months, respectively.
Crystallizing the immunosuppressant allowed the researchers to densely concentrate it, making the whole package small and practical to use. Because crystals take time to dissolve, it allows the approach to work for months at a time. By mediating the shape and size of the crystals, the researchers were able to control how long the mechanism will work for.
“We showed that the drugs released very slowly and in a controlled fashion,” added Farah. “We took those crystals and put them in different types of devices and showed that with the help of those crystals, we can allow the medical device to be protected for a long time, allowing the device to keep functioning.”
Study in Nature Materials: Long-term implant fibrosis prevention in rodents and non-human primates using crystallized drug formulations