A carrier for clinical use of recombinant human BMP-2: dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge.

The clinical applicability of a dehydrothermally cross-linked composite of fibrillar and denatured atelocollagen sponge (DCFD-AS), as a carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) was evaluated in the rat subcutaneous pouch. After four weeks, DCFD-AS with rhBMP-2 formed compact bone, without undergoing significant changes in shape and size, by means of intramembranous ossification. The ultimate size, shape and location of induced new bone was accurately controlled by the carrier. Low antigenicity of soluble atelocollagen, cross-linking without chemicals, the combination of gelatin with fibrillar collagen, and the spongy structure probably all contributed to new bone formation through intramembranous ossification without inducing an inflammatory response. Atelocollagen sponge is easily sterilized, can be stored at room temperature, and can act as a rhBMP-2 carrier without the need for complex procedures.