tissue engineering is a growing field where new materials are being developed for implantation into the body . one important area involves bone graft materials to replace areas of bone lost to trauma or disease . traditionally , graft material may be harvested from the bone of the individual receiving the graft material . however , this requires an additional surgery and additional recovery . bone also may be taken from others , or even cadavers , but this introduces biocompatibility problems as well as the risk of disease transfer . ideally , a biocompatible material is sought that will act as a filler with appropriate mechanical strength , encourage bone healing , and degrade to allow new bone ingrowth without the risk of disease transfer . the present invention is a new composite bone graft material made from biocompatible poly and nano - sized hydroxyapatite particles exposed on its surface using a gas foaming particle leaching method . a further embodiment of this invention involves coating this plga / hydroxyapatite biomaterial with an adherent , fast , uniform coating of a mineral such as apatite . the plga polymer portion of the composite provides sufficient mechanical strength to replace bone and is degradable over time to allow new bone tissue ingrowth . the incorporated hydroxyapatite particles increase the composite material &# 39 ; s osteogenic properties by providing sites for tissue attachment and propagation . finally , a uniform coating of mineral apatite on the surface of this novel biomaterial composite further enhances its osteogenic qualities .