Synthesis of biomimetic collagen-whitlockite composite bone filler

The field of in situ polymer-bioceramic composites represents a novel domain that imparts advancements in bone tissue engineering by its dual angiogenic and osteogenic potential. In this study, we focused on developing an in-situ synthesised collagen-whitlockite (CO-WH) composite for the regeneration and revascularization of small bone defects. The in-situ CO-WH bone filler was prepared in the quantitative ratio of 0.5: 3.6 (i.e. 1:7) of CO: WH. The prepared composite was characterised using TEM, EDAX, XRD, FTIR, TGA and XPS. TEM results indicated the irregular morphology of the in situ CO-WH particles and showed an average particle size of 30 ± 10nm. EDAX and XPS analysis confirmed the presence of the characteristic elements within the composite and while XRD confirmed its crystallinity. FTIR studies confirmed the presence of amine, carboxyl and phosphate functional groups within the developed composite and TGA confirmed its thermal stability upto 900 °C. The ion release was evaluated using ICP analysis, confirming the controlled release of Ca²⁺, Mg²⁺, and PO₄^3– ions from the in situ CO-WH composite. The composite was found to be biocompatible in DFSCs. In vitro cell migration and tube formation assays conducted in HUVECs demonstrated the angiogenic potential of the composite. Similarly, in vitro osteogenic mineralization, differentiation and alkaline phosphatase activity of CO-WH were studied, demonstrating enhanced osteogenic property in DFSCs. Therefore, the synthesised CO-WH composite bone filler acts as a promising application in regenerating small bone defects due to its angiogenic and osteogenic properties.