Chitosan composites with inorganics, morphogenetic proteins and stem cells, for bone regeneration

Resorbable composites are investigated as a means to regenerate bone lost to disease or trauma without auto- or allografts. Nano-sized hydroxyapatite, among various inorganics in composite preparations, is useful for enhancing the biochemical significance and the performances of chitosan in terms of cellular differentiation and proliferation. Composites are also envisaged to include bone morphogenetic proteins and drugs. Coatings of titanium prostheses with the aid of chitosan and hydroxyapatite permit to obtain lasting integration with living bone. Chitosan + silicate hybrids were also synthesized using γ-glycidoxypropyltrimethoxy silane whose epoxy group reacts with the amino group of chitosan. Major aspects of chemical relevance are composition, porosity, surface area and topography of the composites, along with degree of acetylation, molecular size, purity and chemical modification of chitosan.