Effect of SiO2 in situ cross-linked CS/PVA on SrFe12O19 scaffolds prepared by 3D gel printing for targeting

The design of magnetic composite scaffolds with superior properties has the potential to construct a targeted delivery platform with hyperthermia. In this study, strontium hexaferrite (SrFe12O19, SrM) magnetic nanoparticles (MNPs) were obtained by the chemical precipitation method. Non-toxic cross-linked biogels were prepared for adhesive ceramic scaffolds, and chitosan/polyvinylalcohol (CS/PVA)-bonded SrM magnetic nanoscaffolds were successfully prepared by 3D gel printing (3DGP) method. The effects of PVA physical cross-linking and in situ formed SiO2 on the properties of CS-bonded scaffolds were evaluated, and the compressive strengths were increased from 6.13 +/- 2.45 MPa to 8.80 +/- 2.02 MPa and 17.18 +/- 2.15 MPa, respectively. The results showed that the saturation magnetization of SiO2/CS/PVA/SrM composite scaffolds was 59.96 emu/g. In vitro immersion experiments showed that the degradation rates of SiO2/CS/PVA/SrM scaffolds were 4.90% after 28 days, and the in situ SiO2 improved the deposition of calcium salts on the scaffolds. The experiments showed that the SrM magnetic scaffolds could not only concentrate magnetic fields to improve the efficiency of targeting deposition but also achieve a weak targeting process without external magnetic field assistance. In vitro cell proliferation test showed that MC3T3-E1 cells had good adhesion and proliferation on the surface of SiO2/CS/ PVA/SrM scaffolds, which indicated that the scaffolds may be used for bone repairing.