Evaluation of the mechanical properties, in vitro biodegradability and cytocompatibility of natural chitosan/hydroxyapatite/nano-Fe3O4 composite

The main goal of this research was the preparation and evaluation of the mechanical properties, in vitro biodegradability and cytocompatibility, of natural chitosan/hydroxyapatite/nano magnetite (nano-Fe3O4) composite. 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's 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. The obtained results revealed that Si 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 Si and S3 not only before immersion, but also after 9 weeks immersion. Although the bio-minerals were deposited on the surface of all samples during the immersion in Ringer's solution, S2 appeared to have the highest quantity of bio-minerals. According to the weight loss percentage (Delta W(%)), the biodegradation resistance of Si was the lowest. Finally, the cytocompatibility of Sl was greater than that of S2 and S3.