The Biomimetic Mineralization Characteristics Of Modified Electrospun Silk Fibroin Scaffolds In Vitro

[Objectives] This issue by using electrospinning technique prepare modified silk fibroin scaffolds, then via the biomimetic mineralization technique to study the different characteristics of SF/PCL and SF/Gt composite scaffolds in the same conditions, and the difference of three kinds of mineralization methods for same material were investigated, in order to manufacture the ideal mineralization composite scaffold.[Methods]Firstly,to optimize the processing parameters, such as the concentration of spinning solution, distance and voltage, the SF,SF/PCL and SF/Gt composite scaffolds were fabricated by eletrospinning technique and analyzed by scanning electron microscopy(SEM). Secondly,the degradation of SF/PCL, SF/Gt composite scaffolds were tested in vitro. All scaffolds were detected via SEM, Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD).Thirdly,the ideal modified silk fibroin scaffolds were mineralized with ten times simulated body fluid(lOSBF) process, polymer-induced liquid-precursor (PILP) process and alternative soaking solutions(ASS) process.To further analyze the influences of the added componentsnon the scaffolds and the mineralized effects by three different mineralization approaches,all simples were also analyzed by SEM, Energy dispersive spectroscopyEDX, FTIR and XRD.[Results]1.The ideal electrospon conditions:The SF scaffold, concentration between10%to14%, voltage between20Kv～22Kv. The SF/Gt composite, concentration is10%, the voltage between20kV to22Kv, SF:Gt=80:20(w/w). The SF/PCL composite, concentration is10%, voltage is18kV, SF:PCL=70:30(w/w).The concentration of spinning solution is the most important factor influence the fiber diameter.2.Before degradation test, SF/Gt scaffold was treated with75%alcohol solution and anhydrous alcohol solution, SF/PCL scaffold was treated with75%alcohol solution. After the treatment, Solubility of SF/GT scaffold decreased from100%to23.32%,10.71%, and SF/PCL scaffold decreased from10%to less than1%.3.The degradation resction was kept in37℃deionized water for6days, all of smaples analyzed with SEM. The treatment group of SF/Gt scaffold was dissociated after7days, SF/PCL scaffold only found dissolution,and the volume significantly changed after53days, The dissolution of treatment group of SF/PCL scaffold started after72days.4.Hydroxyapatite and approximate hydroxyapatite can formated on the surface of silk fiborin scaffolds via10SBF, PILP and ASS process. The mineralization speed of10SBF is the fastest, and sufficient mineral volume formation by PILP and ASS process need more cycles. In the mineralization process, the quantity and diameter of the pore is as important as the scaffold material, both of them contribute to the mineral transform.[Conclusion] In this study, ideal SF/Gt and SF/PCL scaffolds was successful obtained by eletrospun, and their structure are very close to the extracellular matrix, could be used for tissue engineering. Hydroxyapatite and approximate hydroxyapatite were found on the surface of silk fiborin scaffolds via10SBF, PILP arid ASS process.