As you probably already know, a problem with implantable devices can involve rejection by the immune system because it is not “self.” The foreign-body reaction occurs in response to implants made of many materials, including teflon, polyurethane, silicone rubber, polyethylene, poly(methyl methacrylate), poly(ethylene glycol) (PEG), Dacron, gold, titanium and alumina, including other hydrogels, such as poly(2-hydroxyethyl methacrylate) (PHEMA). Engineers at the University of Washington recently reported being successful in using a synthetic hydrogel biomaterial. These zwitterionic hydrogels fully resisted the body’s natural attack response to foreign objects for at least 3 months after subcutaneous implantation in mice and promoted angiogenesis in surrounding tissue. The UW researchers plan to test this material in humans, likely by working with manufacturers to coat an implantable device with the polymer, then measuring its ability to ward off protein build-up.
Lei Zhang et al., Zwitterionic hydrogels implanted in mice resist the foreign-body reaction, Nature Biotechnology, 2013, DOI: 10.1038/nbt.2580