Comparative Bone Regeneration Potential Studies of Collagen, Heparin, and Polydopamine-Coated Multichannelled BCP Granules.

The current study is a comparative assessment of the bone regeneration potentiality of bone substitutes composed of bioactive polymer-coated biphasic calcium phosphate (BCP) granules. The bone substitutes were primarily composed of multichanneled BCP granules, which were coated separately with biochemical polymer coatings, namely collagen, heparin, or polydopamine (PD), using chemical methods. The morphologic features and chemical structure of the granules and surface coatings were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The biological characterizations in terms of cellular interaction with the bone substitutes in vitro (MTT assay and proliferation) and in vivo (bone regeneration efficacy) were performed and compared with uncoated BCP granules. It was found that PD-coated BCP granules were superior to the others with respect to promoting more rapid healing. Therefore, PD multichannel BCP granule system can be used as a promising injectable bone substitute for clinical applications.

Incorporation of BMP-2 loaded collagen conjugated BCP granules in calcium phosphate cement based injectable bone substitutes for improved bone regeneration.

The objective of the present study was to incorporate surface modified porous multichannel BCP granule into CPC to enhance its in vivo biodegradation and bone tissue growth. The multichannel BCP granule (15wt%) was first coated with collagen subsequent to BMP-2 loading (ccMCG-B). It was then embedded into CPC to form CPC-ccMCG-B system. The newly developed CPC-ccMCG-B system was then examined for SEM, EDX, XRD, setting time, compressive strength, injectability, pH change, BMP-2 release, in vitro as well as in vivo studies and further compared with CPC. Optimized CPC (0.45mL/g) was found based on setting time and compressive strength studies. In vivo studies exhibited improved new bone formation and better degradation of CPC after 2 and 4weeks of implantation as compared to CPC as resulted from effective BMP-2 signaling. Our results suggest that CPC-ccMCG-B system might be used as a promising injectable bone substitutes in clinical applications.