The preparation of chitosan nanowires and its application to hemostasis

• Main Authors: Ying-Chiang Ho, 何應強
• Other Authors: YI-CHANG CHUNG
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/88783806637783089959

碩士 === 國立高雄大學 === 生物科技研究所 === 101 === We used chitosan nanowires as hemostatic materials in this research according to the hemostasis property of chitosan, which can also absorb and activate platelets and enhance the formation of fibrin. The nanowire form of chitosan was expected to display high aspect ratios and high surface areas to interact with blood cells. By treatment of crosslinker, the nanowires was fixed for their morphology and formed a network structure in order to intercept more platelets and erythrocytes to speed up hemostasis occurance. In the preparation of nanowires, we improved the traditional electro-spinning process to fabricate short nanowires by using high-boiling-pointed acetic acid and low-molecular-weighted chitosan. Due to low evaporating property of the solution and less entanglement between polymer chains, the shortened chitosan nanowires could be obtained via collecting nanowires passing through a grounded metal mesh in a basic alcoholic solution. The diameters of nanowires could be controlled via some parameters: precipitating agents, operation voltages, and working distances, and so on. Higher operation voltage generated relatively narrow nanowires. the precipitating agents using different NaOH/ethanol ratios could dominate the morphology of nanowires, affect the precipitation, and change diameters of nanowires. Furthermore, we also used chitosan/PVA to form the co-precipitated nanofibers, and then dispersed via ultrasonic treatment (15 W for 3 min) to form shortened chitosan/PVA nanowires. After drying, purifying, and re-dispersing the nanowires into PBS, the wire-like structure of nanowires could be maintained well. In blood coagulation tests, using tripolyphosphate (TPP) and alginate to crosslink the nanowire surfaces displayed different results for blood coagulation. TPP could enhance fibrin formation but take more time; while alginate-crosslinked chitosan might exhibit high water adsorption to intercept more blood and cells. However, surface-crosslinked chitosan might be neutralized on those positive ammonium groups, decreasing the positive charges on surfaces and also the adsorption and activation of platelets.