Preparation, Characterization Of Electrospun P(LLA-CL) Based Nanofibers And Their Application In Biomedical Areas

Native extracellular matrix (ECM) is a chemically and physically cross-linked complex network of three important classes of biomacromolecules secreted locally by cells. These are fibrous proteins, proteoglycans, and non-fibrous proteins. In a typical connective tissue, structural fibers such as collagen fibers and elastin fibers have diameters ranging from several ten to several hundred nanometers. The nanoscaled fibers entangle with each other to form a nonwoven mesh that provides tensile strength and elasticity for the tissues. The morphology of polymer nanofibers are similar to ECM, and can supply a 3-D environment and more acceptor sites for cell adherence and growth. In this study, electrospinning has been used to fabricate nanofibers as biomemitic ECM for excellent biomaterials. There are many research fields such as materials fabrication, mechanical design and medical device were involved as following in this paper.(1) Chitosan-P(LLA-CL) complex was electrospun into nanofibers as biomemitic ECM first time. In this study, SEM, FTIR, XRD, contact angle, and materials test machine were used to characterize the nanofiber. The cells of fibroblast and PIECs were seeded onto nanofiber mats for adherence and proliferation studies. A new collector with a rotary mandrel has been design and used to fabricate tubular scaffold or aligned nanofiber fibric. The results showed that chitosan-P(LLA-CL) complex nanofiber and its fibric have shown valuable potential application as biomaterials for tissue engineering scaffold, wound dressing, and so on.(2) Heparin contained core-shell fibers and fibric were fabricated using coaxial electrospinning technique. Through TEM, SEM test and Image J software, the morphology and diameter of core-shell fiber were investigated. In cell culturing test, heparin contained fibers have shown obvious inhibit affect on proliferation of fibroblast. Due to the special structure, this kind of fibers are very useful in application as heparin release and tissue engineering scaffold.(3) A new type of covered stent was successfully developed with electropinning technique and the rotary mandrel collector in our study. Electrospun fibers covered stent could be well fixed on the balloon of delivery device, and showed good mechanical properties and morphology in dilation process. After expanding, the fiber fabric on stent could maintain their morphology well and be fixed in artery. As a new type of covered stent with low recoil and infiltration, electropun fibers covered stent showed potential application in clinical treatment of aneurysm..