Preparation, characterization and bioactivities of nano anhydrous calcium phosphate added gelatin-chitosan scaffolds for bone tissue engineering

Gelatin, chitosan and nano calcium phosphate based composite scaffold with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the physico chemical, mechanical and osteogenic properties of 3D porous scaffold by incorporation of dihydrogen calcium phosphate anhydrous (DCPA) nanoparticles into biopolymer matrix with variation in composition in the prepared scaffolds. Scaffolds were prepared from the slurry containing gelatin, chitosan and synthesized nano DCPA particle using lyophilization technique. DCPA nano particles were synthesized using calcium carbonate and phosphoric acid in water-ethanol medium. XRD pattern showed phase pure DCPA in synthesized nanopowder. Scaffolds were prepared by addition of DCPA nanoparticles to the extent of 5-10 wt% of total polymer into gelatin-chitosan solution with solid loading varying between 2.5 and 2.75 wt%. The prepared scaffold showed interconnected porosity with pore size varying between 110 and 200 micrometer. With addition of DCPA nanoparticles, average pore size of the prepared scaffolds decreased. With increase in nano ceramic phase content from 5 wt% to 10 wt% of total polymer, the compressive strength of the scaffold increased. Scaffold containing 10 wt% DCPA showed the highest average compressive strength of 2.2 MPa. Higher cellular activities were observed in DCPA containing scaffolds as compared to pure gelatin chitosan scaffold suggesting the fact that nano DCPA addition into the scaffold promoted better osteoblast adhesion and proliferation as evident from MTT assay and scanning electron microscopic (SEM) investigation of osteoblast cultured scaffolds. A higher degree of lamellopodia and filopodia extensions and better spreading behavior of osteoblasts were observed in FESEM micrographs of MG 63 cultured DCPA containing scaffold. The results demonstrated that both mechanical strength and osteogenic properties of gelatin-chitosan scaffold could be improved by addition of anhydrous dihydrogen calcium phosphate nanoparticles into it.