Enhanced biomineralization and protein adsorption capacity of 3D chitosan/hydroxyapatite biomimetic scaffolds applied for bone-tissue engineering

This work presents the enhanced biomineralization and protein adsorption capacity of 3D chitosan/hydroxyapatite (CS/HAp) biomimetic scaffolds synthesized from natural sources applied for bone-tissue engineering (BTE). The scaffolds were prepared by the freeze-drying method, then characterized by X-ray diffraction, scanning electron microscopy, liquid substitution, swelling behavior, and mechanical strength. Fourier transform infrared spectroscopy was also conducted to investigate the interaction between chitosan (CS) and hydroxyapatite (HAp). The biodegradation, biomineralization and protein adsorption capabilities of the scaffolds were evaluated through tests in vitro. Results showed that the 3D CS/HAp scaffolds exhibited highly porous structures with an average pore size of 265 μm, and mean porosity of 75.01%, respectively; the tensile strength of the scaffolds was 2.45 MPa, matching well with that of cancellous bone. The addition of HAp into the CS matrix efficiently decreased the swelling percentage of the CS/HAp scaffolds and retained the suitable degradation rate of the composite scaffolds; the degradation percentage of the CS/HAp scaffolds was 46.37% after 28 days immersed in a physiological solution. The CS/HAp scaffolds demonstrated a higher biomineralization capability than that of the CS scaffolds, releasing a bone-like apatite layer on their surface after 15 days of incubation in simulated body fluids. The presence of HAp mimicking biological apatite in the composite scaffolds facilitated a higher protein adsorption capability, compared to that of the CS scaffolds. The obtained results suggest that the CS/HAp scaffolds have great potential as biocompatible materials for BTE applications.