Recombinant human bone morphogenetic protein 2 (rhBMP-2) delivery from collagen sponges for bone formation is an important clinical example of growth factors in tissue engineering. Side effects from rhBMP-2 burst release and rapid collagen resorption have led to investigation of alternative carriers. Here, keratin carriers with tunable erosion rates were formulated by varying disulfide crosslinking via ratios of oxidatively (keratose) to reductively (kerateine) extracted keratin. In vitro rhBMP-2 bioactivity increased with kerateine content, reaching levels greater than with collagen. Heterotopic bone formation in a mouse model depended on the keratin formulation, highlighting the importance of the growth factor carrier.
Keywords: bone morphogenetic protein 2; collagen; drug delivery; kerateine; keratose; synthetic bone graft.