Size- and shape-dependent foreign body immune response to materials implanted in rodents and non-human primates

The efficacy of implanted biomedical devices is often compromised by host recognition and subsequent foreign body responses. Here, we demonstrate the role of the geometry of implanted materials on their biocompatibility in vivo. In rodent and non-human primate animal models, implanted spheres 1.5 mm and above in diameter across a broad spectrum of materials, including hydrogels, ceramics, metals and plastics, significantly abrogated foreign body reactions and fibrosis when compared with smaller spheres. We also show that for encapsulated rat pancreatic islet cells transplanted into streptozotocin-treated diabetic C57BL/6 mice, islets prepared in 1.5-mm alginate capsules were able to restore blood-glucose control for up to 180 days, a period more than five times longer than for transplanted grafts encapsulated within conventionally sized 0.5-mm alginate capsules. Our findings suggest that the in vivo biocompatibility of biomedical devices can be significantly improved simply by tuning their spherical dimensions.
Juvenile Diabetes Research Foundation International (Grant 17-2007-1063)
Leona M. and Harry B. Helmsley Charitable Trust (Grant 09PG-T1D027)
National Institutes of Health (U.S.) (Grant EB000244)
National Institutes of Health (U.S.) (Grant EB000351)
National Institutes of Health (U.S.) (Grant DE013023)
National Institutes of Health (U.S.) (Grant CA151884)
National Cancer Institute (U.S.) (Koch Institute Support (Core) Grant P30-CA14051)
Tayebati Family Foundation
Juvenile Diabetes Research Foundation International (Postdoctoral Fellowship Grant 3-2013-178)
United States. Dept. of Defense. Congressionally Directed Medical Research Programs (Postdoctoral Fellowship Grant W81XWH-13-1-0215)