Synthesis, Characterization and in-vitro Study of Chitosan/Gelatin/Calcium Phosphate Hybrid Scaffolds Fabricated Via Ion Diffusion Mechanism for Bone Tissue Engineering

Abstract

In this study, biomimetic scaffolds were designed to investigate calcium phosphate formation via a double diffusion mechanism within a gelatin/chitosan hydrogel in biological pH and temperature. Three types of samples with initial percentages of chitosan (20, 30 and 40 wt. %) were prepared. Diffusion of calcium and phosphate ions through the hydrogel formed a precipitation layer. Samples were freeze dried to form porous scaffolds and soaked in glutaraldehyde to increase their mechanical properties. X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM) were employed to investigate the microstructure and to characterize the prepared scaffolds. Analysis of precipitation indicated the presence of brushite and hydroxyapatite. The amorphous calcium phosphate phase converted into crystalline hydroxyapatite after immersion in simulated body fluid which mimics the formation of hydroxyapatite in the human body. FTIR results suggested the presence of structural hydroxyl and phosphate bonds in the structure of the prepared scaffolds which could be due to the formation of hydroxyapatite. With increasing amount of chitosan in the composite scaffold, the water up-take ability was increased from 380 to 660 %, yield strength and Young’s modulus slightly decreased and the crystalinity of the precipitated phase increased. Mechanical properties obtained from the samples were in the range of cancellous bone. MTT assay results and alkaline phosphatase activity showed prepared scaffolds had proper biocompatibility.