The Frabrication Of CW/PCL Nanocompositetubular Scaffold By Electrostatic Spinning

Polycaprolactone (PCL) has a good application prospect in the field of biomedical materialsdue to its excellent biocompatibility, biodegradability and permeability. However, the lowmechanical properties and poor hydrophilicityof PCL limited its application of scaffold forcardiovascular tissue engineering. Chitosan is a natural biomaterial which has a great applicationin the field of biomedical engineering, food, chemical engineering due to its great properties suchas non-toxic, excellent biocompatibility, good biodegradability, anti-bacteria, easy to form fibersand films.In this work,CW(Chitin Whisker)/PCL nano-composite tubular scaffold was fabricatedby electrostatic spinning, taking advantage of CW, a kind of good reinforcement nanofillerobtained from chitinby hydrochloric acid hydrolysis, to form a three dimensional netstructure inthe matrix, thus enhancing the mechanical properties of this composite.Then, CW/PCLnano-composite tubular scaffold was modified by the loading of heparin. The main details are asfollows:(1) The CW/PCL nano-composite tubular scaffoldwas obtained by electrostatic spinning,with a size of about80nm in length,5nm in innerdiameter,5.5nm in external diameter. Theresearch showed that the diameter of obtained nano-composite fibers and thecrystallizationtemperature of obtained nano-composite fiber tubular scaffold were reduced, andthe melting point, the porosity, the degree of crystallinity and especially the hydrophilicity ofobtained nano-composite fiber tubular scaffold were enhanced as the increase of the concentrationof CW. When the concentration of CWwas20wt%, the surface of nano-compositefiber becamesmooth, and the distribution of diameter was of most great uniformity. And the tensile strengthand the radial compression strength (compressibility is50%) were maximum,3.71MPa and312.7cN, respectively.(2) The modified CW/PCL nano-composite fibertubular scaffold was obtained by adding ofheparin into CW/PCL spinning solution system.Then the release of heparin was studied. It was found that the rate of release and accumulative total release quantity were relatively good whenthe loading content of heparin was0.5%. Then theblood compatibility of this material was alsostudied.The resultsshowed that when the loading content of heparin was0.5%or above, thequantity of platelet adhesion decreased significantly, and the hemolysis rate also greatly reduced.When the loading content of heparin was1.0%, the hemolysis rate was3.1%, which was lessthanthat of medical standard of5%. The recalcification time of this materialhadalso beenprolonged that would delaythe activation of original clotting pathway.