| Biodegradable polyester with good biodegradability and biocompatibility has been a very large potential candidate in biomedical field. With further study on tissue engineering and guided tissue repairing, the higher requirements for biodegradable polyester fiber membrane are put forward. Then many efforts are made to develop the various functions of biodegradable polyester to meet the needs of biomedical applications, such as the insufficient mechanical performance, new drug loading, inflammatory response caused by immune rejection, induced cell growth and other issues. In this paper, biodegradable polyester is functionalized based on the electrospinning method.1. Mechanics: PLLA nanofiber membrane was crosslinked by chemical crosslinking with dicumyl peroxide(DCP) and triallyl isocyanurate(TAIC). By regulating the concentration of DCP and TAIC and a cross-linking temperature, the mechanical properties of the nanofiber membrane are adjusted. Their corresponding properties such as morphology, thermodynamics, mechanics, degradation and cytotoxicity are investigated. Morphology of PLLA fiber is maintained after crosslinking, but its crystallization and melting temperature is influenced by chemical crosslinking. The membranous tensile strength and modulus not only climb with TAIC concentration increasing, but also depend strongly on crosslinked temperature which the best is 140 oC. Compared to neat PLLA, degradation rate of the crosslinked PLLA membrane is slower. The results suggest that the chemical crosslinking improves the mechanics properties of PLLA fiber membrane and keeps its mechanics stability longer, making it more suitable for tissue engineering.2. Drug release: Electrospun poly(lactide-co- glycolide)(PLGA) fiber membrane loaded XN was prepared using a co-solvent system of chloroform and dimethylformamide. To eHA-g-PLLAnce its biological functionality as tissue engineering scaffolds, 5 wt% hydroxyapatite grafted poly(L-lactic acid)(HA-g-PLLA) was blended into the spinning solution. The purpose of the present work was to disclose the effect of blending HA-g-PLLA on the corresponding properties of the medicated fiber membrane including morphology, thermodynamics, wettability, drug release as well as mechanics. XN and HA-g-PLLA could be well blended with PLGA to make fibers. Blending HA-g-PLLA not only turned amorphous XN-loaded PLGA fiber membrane into crystal structure, but also changed the membranous wettability. Various medicated fiber membranes exhibited the sustained controlled release profiles. And the drug release rate of the ternary membrane blended with HA-g-PLLA was slower compared to XN-loaded PLGA binary membrane. For the ternary membrane, the drug release accelerated with increasing XN content. A model was proposed to account for the drug release process. Tensile testing also showed that at 10 wt% of XN, the comprehensive mechanics of the ternary membrane was preferable to the binary.3. Conductive property: To improve interface compatibility of polypyrrole(PPy) with bio-polyesters, poly(e-caprolactone) grafted PPy(PPy-g-PCL) are synthesized in this section. Then it is blended with PLGA to make parallel orientation structure composite nano-fiber membrane via adjusting drum speed. The effects of PPy-g-PCL on the membranous properties such as morphology, thermal stability, electrochemical activity, wettability, mechanical properties are evaluated. The results showed that blending PPy-g-PCL had no significant effect on the fibrous morphology, but the improvement of the membranous hydrophilic and tensile properties. In view of a microscopic electrical conductivity of PPy-g-PCL and fibrous parallel arrangement structure, the composite fibrous membrane has great potential in inducing cell growth, guided repair muscle tissue, nerve tissue, etc. has directivity organization, taking into account... |
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