Effect of hydroxyapatite as a component of biostable composites on population and proliferation of mesenchymal stem cells.

Three groups of biostable composite materials were studied. The initial binder polymers (polymethylmethacrylate, polyamide-12, superhigh-molecular-weight polyethylene) and hydroxyapatite-containing composites on the basis of these polymers were tested. Biostable polymers, including those containing hydroxyapatite, were nontoxic for fibroblasts and mesenchymal stem cells: the adhesion parameters for these cells were maximum for polyamide-12 and superhigh-molecular-weight polyethylene and did not depend on the presence of hydroxyapatite. Cell adhesion to "pure" polymethylmethacrylate was significantly lower than to other composites, but increased after integration of hydroxyapatite. The efficiency of proliferation of fibroblast and mesenchymal stem cell on the surface of polyamide-12 and superhigh-molecular-weight polyethylene was maximum and did not depend on the presence of hydroxyapatite. The efficiency of cell proliferation on the surface of "pure" polymethylmethacrylate was low, but increased significantly if it was combined with hydroxyapatite, particularly in areas of mineral particles accumulation. It seems that the presence of high amounts of hydroxyapatite in polymethylmethacrylate samples promotes cell adhesion and proliferation.