An osteogenic grafting complex combining human periosteal sheets with a porous poly( l -lactic acid) membrane scaffold: Biocompatibility, biodegradability, and cell fate in vivo

In this in vitro study, novel porous poly(l-lactic acid) membranes were developed to improve periosteal sheets by promoting initial adhesion of periosteal tissue segments and stimulating the formation of a viable multilayered cellular sheet. The biocompatibility, biodegradability, and osteogenicity were evaluated using human periosteal tissue segments cultured on porous poly(l-lactic acid) membranes; the periosteal sheets were osteogen induced and were then implanted in the dorsal subcutaneous tissue of nude mice. In vivo, the membrane degraded into clusters of membrane particles separated by wide cracks; fibroblastic cells invaded along with small blood vessels from the surrounding mouse connective tissue. In osteoinduced periosteal sheets, the membrane clusters were surrounded by numerous capillaries and a number of tartrate-resistant acid phosphatase–positive, multinucleated cells. Neither severe inflammation nor fibrous encapsulation was observed throughout the implantation (~12 weeks). These porous poly(l-lactic acid) membranes were highly biocompatible and functioned well as biodegradable scaffolds that could enhance the use of osteogenic periosteal sheets in therapy.