Biosilicated collagen/beta-tricalcium phosphate composites as a BMP-2-delivering bone-graft substitute for accelerated craniofacial bone regeneration

Abstract

Background: Bioceramic beta-tricalcium phosphate (beta-TCP) is used as a bone-grafting material and a therapeutic drug carrier for treatment of bone defects in the oral and maxillofacial regions due to the osteoconductivity and biocompatibility. However, the low mechanical strength and limited osteoinductivity of beta-TCP agglomerate restrict bone regenerating performance in clinical settings. Methods: Herein, a biomimetic composite is proposed as a bone morphogenetic protein-2 (BMP-2)-delivering bone graft substitute to achieve a robust bone grafting and augmented bone regeneration. Results: The sequential processes of brown algae-inspired biosilicification and collagen coating on the surface of beta TCP enable the effective incorporation of BMP-2 into the coating layer without losing its bioactivity. The sustained delivery of BMP-2 from the biosilicated collagen and beta-TCP composites promoted in vitro osteogenic behaviors of pre-osteoblasts and remarkedly accelerated in vivo bone regeneration within a rat calvarial bone defect. Conclusions: Our multicomposite bone substitutes can be practically applied to improve bone tissue growth in bone grafting applications with further expansion to general bone tissue engineering.