ABSTRACT
In prior work we have studied the mineralization of collagen, in the absence of other non-collagenous proteins, by nucleation and precipitation of calcium phosphates. 1 In this article we describe the results of an in vivo experiment with this mineralized collagen. The experiment is designed to test the material as a potential substitute for autograft bone and for delivering bone growth factors like BMPs (bone morphogenic proteins) to foster bone formation. Collagenous matrix 2 and demineralized bone 3–5 are being used for delivering such bone inducing growth factors. Other bio-active matrices being considered are polylactide-glycolide co-polymers, 6 fibrin, 7 porous hydroxyapatite, 8 tricalcium phosphate 9 and other calcium-rich minerals. 10,11 The overall objective of this study is the evaluation of mineralized collagen, nanophase composite of collagen and hydroxyapatite, for its osteoconductivity and its ability to express the incorporated bone morphogenic protein-2 (BMP-2) in vivo. Further these properties of mineralized collagen are compared with other bioactive matrices: [a] type-I collagen, [b] polylactide glycolide (1:1) co-polymer, and [c] fibrin glue. The results of the study demonstrate that mineralized collagen may serve as a substitute for autograft bone and for the delivery of BMP-2.
