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 com-posite 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 prolifera-tion. 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 abil-ity 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
Liying SunShan LiKaifeng YangJunchao WangZhengjun LiNianhua Dan
Silicic acid,commonly derived from cheap and easily available sodium silicate,has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach.However,leather tanned with silicic acid alone is poor in storage stability,which limits its practical application in leather production.In this work,a new environment-friendly combination tannage based on silicic acid and plant tannin was developed to address this issue along with improving the comprehensive performances of leather.The obtained leather was characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and so on.The results showed that compared with leather tanned with silicic acid alone,the leather tanned with this combination method possessed improved thermal stability,enhanced mechanical properties,acceptable softness,appropriate hydrophilicity,and especially enhanced storage stability.More importantly,the combination tanned leather with 1:1 of the mass ratio of silicic acid to vegetable tannin(composed of valonea extract and mimosa extract with the same weight)had more prominent comprehensive performances.In addition,the results demonstrated that hydrogen bonding played an important role in the combination tanning process.Furthermore,the hydrogen bonds generated between phenolic hydroxyl groups of polyphenols with silicon hydroxyl groups of silicic acid molecules inhibited the excessive condensation of Si-OH groups between themselves.Subsequently,the assessment of environmental impact revealed the value of BOD 5/COD of the wastewater produced in this combination tanning process is more than 0.3,indicating the chrome-free combination tannage based on silicic acid and plant tannin was an environment-friendly tanning technology.These findings therefore indicated that a new chrome-free tanning method with silicon and biomass materials as main tanning agents has potential practical application prospect in leather production.
Zetian ZhangYang LiuJunchao WangTaoling XieLiying SunZhengjun Li
