Microspheres of collagen/beta-TCP with an open network fibrillar structure strengthened by chitosan

A novel method of preparing collagen/beta-tricalcium phosphate microspheres with chitosan as the mechanical strength enhancer has been developed in this study. The process involved firstly droplet formation by discharging a mixture of collagen, beta-tricalcium phosphates and alginate into an aqueous solution of CaCl(2) by extruding through an air jet-syringe at 4 degrees C. The gel beads thus formed were collected and subsequently coated with chitosan to stabilize the surface of gel bead. Collagen within the gel beads was then reconstituted while the entrapped alginate was liquefied and drained by incubating in phosphate buffer at 37 degrees C. Microspheres comprised of fibrillar collagen and well-dispersed beta-tricalcium phosphate particulates were obtained by this process. And the mechanical strength of these microspheres was significantly enhanced by chitosan coating. These chitosan-coated collagen/beta-tricalcium phosphate microspheres have an open fibrillar network structure with a great potential for future application as biodegradable bone grafting materials.