Polycaprolactone strengthening keratin/bioactive glass composite scaffolds with double cross-linking networks for potential application in bone repair

In this study,we aimed at constructing polycaprolactone（PCL） reinforced keratin/bioactive glass composite scaffolds with a double cross-linking network structure for potential bone repair application.Thus,the PCL-keratin-BG composite scaffold was prepared by using keratin extracted from wool as main organic component and bioactive glass（BG） as main inorganic component,through both cross-linking systems,such as the thiol-ene click reaction between abundant sulfhydryl groups of keratin and the unsaturated double bond of 3-methacryloxy propyltrimethoxy silane（MPTS）,and the amino-epoxy reaction between amino groups of keratin and the epoxy group in（3-glycidoxymethyl）methyldiethoxysilane（GPTMS） molecule,along with introduction of PCL as a reinforcing agent.The success of the thiol-ene reaction was verified by the FTIR and 1H-NMR analyses.And the structure of keratin-BG and PCL-keratin-BG composite scaffolds were studied and compared by the FTIR and XRD characterization,which indicated the successful preparation of the PCL-keratin-BG composite scaffold.In addition,the SEM observation,and contact angle and water absorption rate measurements demonstrated that the PCL-keratin-BG composite scaffold has interconnected porous structure,appropriate pore size and good hydrophilicity,which is helpful to cell adhesion,differentiation and proliferation.Importantly,compression experiments showed that,when compared with the keratin-BG composite scaffold,the PCL-keratin-BG composite scaffold increased greatly from 0.91±0.06 MPa and 7.25±1.7 MPa to 1.58±0.21 MPa and 14.14±1.95 MPa,respectively,which suggesting the strong reinforcement of polycaprolactone.In addition,the biomineralization experiment and MTT assay indicated that the PCL-keratin-BG scaffold has good mineralization ability and no-cytotoxicity,which can promote cell adhesion,proliferation and growth.Therefore,the results suggested that the PCL-keratin-BG composite scaffold has the potential as a candidate for application in bone regeneration field.