Researchers at MIT have developed a simple and versatile method to prevent scar tissue formation around implanted medical devices, such as pacemakers, which typically trigger immune reactions. By coating the devices with a layer of hydrogel adhesive, fibrosis can be avoided, ensuring the proper functioning of the devices. This approach can be applied not only to pacemakers but also to implantable devices used for drug delivery or cell therapy.
The "invisibility cloak" is made of a hydrogel containing a crosslinked polymer, polyacrylic acid, which rapidly absorbs moisture from wet tissues. Once water is absorbed, the NHS ester chemical groups embedded in the polyacrylic acid form strong bonds with proteins on the tissue surface in just about 5 seconds.
In experiments where the adhesive was applied to a polyurethane device and implanted in rats' abdominal walls, intestines, stomachs, lungs, or hearts, no significant scar tissue was found upon device removal weeks later. Similar results were observed in other animal models over a period of three months, showing no fibrosis regardless of the implantation site.
Analysis of the animals' immune responses through RNA sequencing and fluorescence imaging revealed that immune cells like neutrophils began to infiltrate the area and mount an attack upon the first implantation of the adhesive-coated device. However, the immune system quickly ceased its response before scar tissue formation, indicating a mechanical interaction between the adhesive and the tissue that prevents immune attacks.
