Preparation and Biodegradation Behavior of Natural Chitosan/Hydroxyapatite/Nano-Fe₃O₄ Composite for Bone Tissue Engineering

Objectives: The main goal of this research was to prepare and evaluate the mechanical properties, in vitro biodegradability and cytocompatibility, of natural chitosan/hydroxyapatite/nano magnetite (nano-Fe₃O₄) composite.
Methods: Different ratios of these components were investigated, including chitosan/hydroxyapatite: 4/4 (S1), chitosan/hydroxyapatite: 4/6 (S2), and chitosan/hydroxyapatite: 6/4 (S3). Mechanical properties of fabricated composites were examined using bending and compression tests before immersion, and after 2 and 9 weeks of immersion in the ringer solution. Scanning electron microscope (SEM) was employed for observing the bending fracture surface and analyzing the degradation morphology. Human mesenchymal stem cells (hMSC) were also cultured on the samples in order to assess the cytocompatibility.

Results: The obtained results demonstrated that S1 had the highest bending strength before immersion, while S3 had the highest bending strength after 9 weeks immersion. Compressive strength of S2 was greater than that of S1 and S3 not only before immersion, but also after 9 weeks of immersion. Although the bio-minerals were deposited on the surface of all samples during the immersion in ringer solution, S2 appeared to have the highest quantity of bio-minerals. According to the weight loss percentage (ΔW(%)), the biodegradation resistance of S1 was the lowest. Finally, the biological studies demonstrated that the cytocompatibility of the S1 sample was greater than the S2 and S3 samples.

Conclusions: The obtained experimental results ascertain that natural chitosan/hydroxyapatite/nano-Fe₃O₄ composite deserves consideration for bone tissue engineering.