Study On Preparation Of POC Elastomer Micro/Nanofibers By Electrospinning

Biomaterials have gradually penetrated into various fields of medicine. In numerous suitable materials, poly(1,8-octanediol citrate)(POC) is a kind of thermoset elastomer with excellent biological compatibility and its synthetic process is simple and non-toxic. The micro/nanofibers made by electrospinning can mimic the extracellular matrix, and have great application prospects in drug controlled release, wound healing and tissue engineering scaffolds.In this paper, the synthesized POC prepolymer was used as raw material, and poly(L-lactic acid)(PLLA) as supporter polymer or pullulan(Pullulan) as shell polymer for electrospinning to obtain micro/nanofiber mats.The advantages of the POC and electrospinning were combined to take full advantage of the elastomeric characteristic of POC to apply it in regenerative medicine field.The main results are as follows:1. POC prepolymer was prepared by melt polycondensation. The mixture of POC prepolymer and PLLA with different proportions were used for electrospinning and POC/PLLA blend fiber mats were obtained after thermosetting. The morphology and properties of the POC/PLLA fiber mats were characterized by SEM, DSC, DMA and other testing methods. The conclusions were as follows: fibrous mats could be obtained when the proportion of POC and PLLA was not more than 50/50. With the increase of POC, fiber diameter increased gradually, the hydrophilicity enhanced, the in vitro degradation rate increased and mechanical properties of the blend fiber mats were improved in comparison to PLLA fiber mat. The comprehensive mechanical performance of POC/PLLA:50/50 fiber mat was the best. The addition of POC caused the thermal stability of the fiber mats decreased. The in vitro studies of fibroblast cells(L929) showed that POC/PLLA was not cytotoxic and had good histocompatibility.2. POC/PLLA:50/50 electrospun micro/nanofiber mats/scaffolds with different properties were prepared by conjugate electrospinning, and using high-speed rotation roller and tubular scaffold roller. SEM, DSC, WAXD and other testing methods were used to characterize their properties. Fibers from high-speed rotation were neatly and closely arranged with small diameter and low porosity. L929 fibroblast spread along the fiber orientation direction and the tensile strength in this direction was as high as 8.39±0.83 MPa; Fibers from conjugate electrospinning were crimping with larger porosity and pores, which was appropriate for the cells to transfer into the inner layers from the surface; Fibes in tubular scaffold was disorderly arranged with the minimum porosity, had the highest crystallinity and could withstand repeated compression..3. The POC/Pullulan fiber mats were prepared by coaxial electrospinning, and the POC elastomer fiber mats were obtained after thermosetting and washing by water. The structure and properties were characterized by FTIR, TEM, DMA, etc. The higher concentration of POC solution was used in the core layer, the larger diameter and pore the fiber mats had. The thermal stability and mechanical performance of the fiber mats were the best when POC concentration was 50%. Its tensile strength was 1.21±0.13 MPa, its tensile modulus was 5.58±0.66 MPa, and its elongation at break was 111.70±8.68%. It had a good biocompatibility, which met the basic characteristics of the bioelastomer.