Preparation Of PGS Based Porous Elastomer Scaffolds For Skin Tissue Engineering

In this paper,porous PGS scaffolds,porous mSF/PGS compound scaffolds and porous CS/PGS compound scaffolds with excellent elasticity,tunable degradation rate and good biocompatibility were fabricated through particulate leaching method by using poly(glycerol sebacate)(PGS)as a matrix and the silk fibroin microfibers and chitosan as modifiers.Through analyzing the micromorphology,porosity,water absorption,in vitro degradation and cell culture experimental results,the relationship among the mass ratio of porogen,the types and concentration of modifier,and the degradability and biocompatibility of these porous scaffolds were discussed.In this case,the influence factors and change tendency of the degradability and biocompatibility of the scaffolds can be obtained,which can provide new technologies for the design,fabrication and investigation of PGS based compound scaffolds,and especially provide theoretical and experimental foundation for the applications of PGS based compound scaffolds in the field of skin tissue engineering.Firstly,the appropriate crosslinking time for PGS was determined by the rheological experiments,and the porous PGS scaffolds with different porosity were fabricated by particulate leaching method with sodium chloride as the porogen.The influences of the porous structure and different mass ratio of porogen on the micromorphology,wettability,water absorption,crosslinking degree,degradation rate and biocompatibility of porous scaffolds were discussed.The experimental results reveal that porosity and connectivity between pores increase with the proportion of sodium chloride.Compared with dense PGS scaffolds,porous PGS scaffolds show a bit worse hydrophilicity,but higher water absorption due to the porous structure.The higher the mass ratio of porogen is,the greater the crosslinking degree is,and the slower the degradation rate of PGS is.The vitro cell culture experimental results indicate that the 65NaCl-PGS scaffold shows the best biocompatibility.Therefore,the porous PGS compound scaffolds were fabricated with 65wt% porogen.Secondly,the silk fibroin microfibers(mSF)were prepared by hydrolyzation method,and then were blended with PGS prepolymer to fabricate the porous mSF/PGS compound scaffolds.Similar to the porous PGS scaffolds,the porous mSF/PGS compound scaffolds show very high pore connectivity.The addition of silk fibroin microfibers slows down the degradation rate of PGS.The in vitro cell culture experimental results show the successful attachment,proliferation and migration of the fibroblast on the scaffolds,and prove that the silk fibroin microfibers can promote the growth of cells.Compared with the porous PGS scaffolds,the cells on the mSF/PGS scaffolds secrete collagenous fibers.Thirdly,porous CS/PGS compound scaffolds were prepared by blending chitosan(CS)with PGS prepolymer.The CS/PGS compound porous scaffolds exhibit high pore connectivity.The crosslinking degree of the CS/PGS scaffolds increases with the concentration of chitosan,but the increment is smaller than that of mSF/PGS scaffolds.Although the addition of chitosan makes the PGS scaffolds hydrophobic,the scaffolds still show very high water absorption as a result of the existence of porous structures.The degradation experimental results imply that chitosan slows down the degradation rate of PGS to some extent.Due to the antibacterial effect of chitosan,CS/PGS scaffolds show better cell proliferation than mSF/PGS scaffolds.Finally,further investigation expectation of PGS was brought forward.The research outcomes of PGS in skin tissue engineering not only expand our understanding toward the PGS material itself,but also obtain the detailed conditions of PGS used in artificial skin field.A preliminary research frame is established,and it can provide reliable experimental and theoretical basis for the application of PGS in the fields of artificial skin and tissue engineering.