Fabrication of recombinant human bone morphogenetic protein-2 coated porous biphasic calcium phosphate-sodium carboxymethylcellulose-gelatin scaffold and its In vitro evaluation

Fabrication of bone substitutes, which are a combination of bio-ceramics and bio-polymer, is performed to meet the demand for bone regeneration after fracture or disease. In this study, sodium carboxymethylcellulosegelatin (NaCMC-GEL) hydrogel scaffold where the ratio of NaCMC and GEL was 1:2 and biphasic calcium phosphate (BCP) loaded NaCMC-GEL where the ratio of BCP, NaCMC and GEL was 1:1:2 hydrogel scaffold were fabricated successfully by the freeze-drying method. These hydrogel scaffolds were crosslinked by 0.75wt% genipin solution to check the swelling and ensure optimum degradation. Then BCP-NaCMC-GEL hydrogel was coated with recombinant human bone morphogenetic protein-2 (rhBMP-2). Detailed morphological and material characterization, such as porosity, micro-structural analysis, and chemical constituents of NaCMC-GEL and BCP-NaCMC-GEL hydrogel scaffolds was carried out. The study demonstrates that these hydrogel scaffolds have a porous structure and the pore size is optimum for bone tissue regeneration. PBS uptake and degradation behavior of the NaCMC-GEL, BCP-NaCMC-GEL and BMP-2-BCP-NaCMC-GEL hydrogel scaffolds were also observed. BMP-2-BCP-NaCMCGEL hydrogel scaffold showed higher cell viability, cell attachment, and proliferation of pre-osteoblast MC3T3-E1 cells than the NaCMC-GEL, BCP-NaCMC-GEL scaffolds, which was confirmed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, live-dead assay, and immunofluorescence assay. The BMP-2 release profile from BMP-2-BCP-NaCMC-GEL scaffold was also shown. The observations show that BMP-2-coated BCPNaCMC-GEL hydrogel scaffold is a promising material for bone tissue regeneration.