Mechanical, physical, and biological properties of polycaprolactone/ Mg-doped SrFe12O19 nanocomposite scaffolds for bone tissue engineering applications

Abstract

Nowadays, the utilization of 3D printing has become common in the construction of composite scaffolds. In this research, the co-precipitation method was applied to synthesize pure strontium hexaferrite oxide (SrFe12O19) and magnesium-doped strontium hexaferrite oxide nanoparticles (Mg-SrFe12O19). The synthesized SrFe12O19 nanoparticles had a spherical morphology with a mean size of 60 nm and magnetization (Ms) value of 54.38 emu/g. The Mg-SrFe12O19 also had a spherical morphology with a mean particle size of 46 nm and a magnetization value of 29.89 emu/g. The produced polycaprolactone composite scaffolds containing different amounts (0, 25, 50, and 75 wt) of reinforcement were fabricated by the 3D robocasting printing method. Based on the results of the compression test, the 25 wt addition of the pure SrFe12O19 nanoparticles to the polycaprolactone scaffold increased the compressive strength from 2.87 to 11.68 MPa compared to the 100 wt pure polycaprolactone scaffold. Furthermore, the polycaprolactone nanocomposite scaffold containing 25 wt Mg-SrFe12O19 also increased the compressive strength compared to the pure polycaprolactone scaffold to 12.94 MPa. Therefore, the 25 wt reinforced scaffold was chosen as the optimal sample. The contact angles of the pure polycaprolactone SrFe12O19 and Mg- SrFe12O19 reinforced polycaprolactone scaffolds were 77.17, 68.53, and 35.58 degrees, respectively. The values indicate the significant effect of doping magnesium on the wettability. The degradability of the 3D-printed scaffolds containing 25 wt of the two different reinforcements was evaluated for 28 days immersing in phosphate-buffered saline (PBS) solution. The results revealed that the degradability was higher for the Mg-SrFe12O19 after 28 days compared to the composite scaffold reinforced by pure SrFe12O19 reinforcement. Moreover, it was shown that the bioactivity and cell adhesion of MG63 cells for the scaffolds reinforced by Mg-SrFe12O19 have increased in laboratory conditions. Based on the MTT test, it was observed that both of the scaffolds were non-toxic. The results obtained in this study, suggest that polycaprolactone nanocomposite scaffolds containing 25 wt of Mg-SrFe12O19, made by the 3D robocasting printing method, are suitable for bone tissue engineering.