| Objective: To construct 3D printed silk fibroin(SF)/polyvinyl alcohol(PVA)/ nano-hydroxyapatite(n-HA)composite scaffolds,and explore its feasibility as a scaffold for bone tissue engineering and its effect on osteogenesis and degradation,by testing its physical and chemical properties,biological properties,acute toxicity test.Methods: The SF/PVA/n-HA scaffolds and the PVA/n-HA scaffolds were respectively prepared by 3D printing technology to test the pore size,compressive mechanical properties and biocompatibility,acute toxicity detection,gross observation after replantation of rat renal capsule,HE staining and RT-PCR.When planting animals,the materials are divided into 3 groups: experimental group 1-SF /PVA /n-HA scaffolds;experimental group 2-PVA /n-HA scaffolds.Control group-empty scaffold group.Result:(1)Under scanning electron microscope,SF/PVA/nHA scaffold had regular scaffold structure and clear network structure,exhibited continuous communicating branch,well-connected overlap joint,and uniform scaffold space.Under the same multiples,the network structure continuity of PVA/nHA scaffold was poorer.(2)Compressive mechanical properties: Under the same stress(10 Mpa),the strain of SF/PVA/nHA scaffold was larger than that of PVA/nHA scaffold(P<0.05).(3)The pore size of group SF/PVA/nHA scaffold(59.87±1.33 %)was significantly larger than PVA/nHA scaffold(46.26±1.21 %)(P<0.05).(4)Cell toxicity detection: There was no significant difference in cell appreciation rate between two groups of scaffolds at different time points(1day,3day,5day)(P>0.05).(5)After intraperitoneal injection of material extract,the rats in each group survived well during the observation period of 72 h,and there was no difference in body weight between the groups(P>0.05).(6)HE staining:At the end of February,tissue ingrowth was observed in the solid scaffold material in group 1.RT-PCR: The Detected genes include Runx-2,Col,Rankl,IL-1.The expression of these four genes in experimental group 1 and experimental group 2 was high at the end of January and February,which had statistical significance compared with the control group(P<0.05).The expression of Col and Runx-2 in experimental group 1 was not different from that in experimental group 2 at the end of February(P>0.05),but the expression of Runx-2,Col,Rankl,IL-1 in experimental group 1 was higher than that in experimental group 2 at each time point(P<0.05).Conclusions: 3D printed SF/PVA/n-HA scaffolds have good biocompatibility,compressive mechanical properties and porosity.3D printed SF/PVA/n-HA scaffolds can promote the expression of osteogenesis-related genes(Runx-2,Col)and osteoclast-related genes(Rankl,IL-1).Based on HE staining of experimental group 1 at the end of February,we infer that 3D printed SF/PVA/n-HA scaffolds with silk fibroin can accelerate degradation. |
