【作者】 侯莹；

【导师】 许并社； 魏丽乔；

【作者基本信息】 太原理工大学 ， 材料学， 2010， 硕士

【摘要】 随着科学技术的发展,与人类健康休戚相关的医用生物材料成为目前研究的热点。天然胶乳凭借其良好的生物相容性以及加工操作性能,在医用介入导管方面得到广泛的应用。但目前医用胶乳材料抗菌性能不足,易引发感染,从而增加了患者的痛苦与负担。因此,对天然胶乳有目的地进行抗菌改性,可以扩大其在生物医药领域的应用。壳聚糖是自然界唯一大量存在的天然碱性多糖,是目前研究最多的天然抗菌剂之一。它具有良好的生物相容性、可生物降解性及无毒副作用等特性,但是由于其溶解性差,限制了它在很多领域的应用。本文采用两种方法对壳聚糖进行水溶性改性,提高其溶解性能,一种是以壳聚糖（CTS）为原料,过氧化氢为氧化剂,通过氧化降解法制备低分子量壳聚糖,并对其进行纳米化处理;另一种是使用壳聚糖作为原料,异丙醇为介质,通过氯乙酸修饰,在碱性环境中制备O-羧甲基壳聚糖。分别探讨了反应过程中不同因素对反应结果的影响;使用红外光谱（IR）、扫描电镜（SEM）、透射电镜（TEM）、X射线衍射（XRD）分析观察了两种产物的微观形貌和结构变化;并采用吸光度法检测分析了两种产物对大肠杆菌的抗菌能力。结果表明:1、低分子量壳聚糖制备过程中m（H₂O₂）:m（CTS）=3:10、5gH₂O₂在4h内滴加完毕为宜,反应的最佳温度为60℃,最佳反应时间为5h;制备的低分子量壳聚糖环结构保持完整,氧化断键发生在β-（1,4）-糖苷键上;形貌为分散的、均匀的球状或类球状小颗粒,平均粒径为0.5μm左右;纳米化后平均粒径为20nm左右;降解后结晶度明显下降,水溶性提高;对大肠杆菌的抑菌率为94.1%,具有持续、良好的抗菌抑菌效果。2、O-羧甲基壳聚糖制备反应的最佳温度为30℃;在滴加氯乙酸的过程中,搅拌速度为200²30r/min,滴加停止时,80¹00r/min的搅拌速度为最佳;产物结构疏松分散,大部分呈颗粒状;结晶度有一定的下降,水溶性得到改善;对大肠杆菌的抑菌率为91.3%,具有持续、较好的抗菌抑菌效果。本文使用以上制备的两种改性壳聚糖作为抗菌剂,采用物理共混法使其与天然胶乳均匀混合,分别得到低分子量壳聚糖抗菌胶乳和O-羧甲基壳聚糖抗菌胶乳。探讨了反应过程中pH值、搅拌速度、温度对结果的影响;使用红外光谱（IR）、扫描电镜（SEM）等测试手段对共混改性前后天然胶乳的结构和形貌进行了观察、对比分析;通过抑菌环抗菌性能测试,研究了抗菌乳胶对大肠杆菌的抗菌抑菌能力。结果表明:最佳的反应条件为:pH值8.0⁹.0,搅拌速度200²80r/min,温度18℃²5℃;胶乳与低分子量壳聚糖混合后结合紧密,两者之间的结合界面没有明显的变化,与O-羧甲基壳聚糖混合后有细小的裂纹产生;抑菌环检测显示,低分子量壳聚糖抗菌胶乳形成抑菌环的直径为13.5 mm,O-羧甲基壳聚糖抗菌胶乳形成的抑菌环直径为12.5 mm,远远大于抗菌性能认定标准;对性能更好的低分子量壳聚糖抗菌胶乳进行动物体内相容性实验,结果表明其在动物体内相容性良好,无细胞毒性。更多还原

【Abstract】 With the development of science and technology, biomedical materials which are closely related to human health become hotspot in research. Natural latex has been applied extensively in the field of medical interventional catheter because it’s excellent biocompatibility and physical properties. However, the sufferers may be infected easily because medical natural latex without antibacterial property, which means more pain and more burdens. Hence, the antibacterial natural latex has been researched for expanding its applications in the filed of biology medical area. Chitosan is the only nature alkaline polysaccharide existing in great numbers. It has excellent biocompatibility, biodegradability and non-toxic or side effects. But its application is limited in many areas because of its poor solubility.In this paper, the chitosan were modified for enhance its water-solubility used two kinds of methods. The nanometer low molecular chitosan was prepared by oxidation methodology and nanotechnology with hydrogen peroxide as the oxidant. The O-carboxymethyl chitosan was prepared in alkaline cultures of isopropyl alcohol with chloroacetic acid as modified agent. The influence of different factors on the process of reaction was studied. The structures and morphologies of two kinds of products were characterized by IR, SEM, TEM and XRD, while antibacterial effect against Escherichia coli of the two products was tested by absorbance ratio method. These results as follows:1. The preparation technological conditions of low molecular chitosan were that: the molar ratio of hydrogen peroxide to chitosan was 3:10, the drop speed of hydrogen peroxide was 5g/4h, the reaction temperature was 60℃and the time of produce was 5h. The low molecular chitosan prepared have intact structure of pyran ring. The oxidizing bond breaking occurred inβ-(1,4)-glycosidic bond. Low molecular chitosan particles are spherical with particle sizes of 0.5μm and 10nm after nanotechnology. The crystallinity of chitosan decreased obviously and the solubility increased after degradation. Low molecular chitosan had excellent and sustaining anti-bacterial performance against Escherichia coli.2. During the preparation of O-carboxymethyl chitosan, the best temperature of reaction was below 30℃, the stirring speed was 200~230r/min, after dropping of chloroacetic acid, the stirring speed was dropped to 80~120r/min. The structure of the product is loose and decentralized. Most of its particles are granular. The crystallinity of chitosan decreased and the solubility increased. O-carboxymethyl chitosan had good and sustaining antibacterial performance against Escherichia coli.Two kinds of antibacterial latex were prepared used nanometer low molecular chitosan or O-carboxymethyl chitosan as antibacterial agent and natural latex by mechanical blending method. The influence of pH value, stirring speed and temperature on the process of reaction were investigated. The structure and morphologies of unmodified and modified natural latex were characterized by IR and SEM. Antibacterial performance of modified natural latex against Escherichia coli was analyzed by inhibition ring test method.The optimum parameters of blending reaction were pH value 8.0~9.0, stirring speed 200~280r/min and temperature 18℃~25℃. Low molecular chitosan particles were combined with latex closely and evenly dispersed in latex matrix. The bonding interface did not change significantly. Slightly cracks appeared on the surface of latex after blended with O-carboxymethyl chitosan. The result of inhibition ring test indicated that the two antibacterial latexes have well antibacterial property, with the inhibition ring’s diameter far more than 7mm. The experiment of compatibility in vivo was processed using low molecular chitosan antibacterial latex with better properties. The result showed the antibacterial latex had excellent compatibility and no cytotoxicity.更多还原