论文总字数：20937字

摘 要

壳聚糖氧化后可得到双醛基化壳聚糖（2,3-di-aldehyde chitosan DACT）；通过发散法制备三代赖氨酸树状多肽（PLLD G₃），其上的氨基可与DACT上的醛基发生席夫碱反应，通过化学交联制备抗菌复合水凝胶。利用FT-IR、¹H NMR和ESI-MS分别对DACT和PLLD G₃进行结构表征，并测定DACT的氧化度和分子量。利用流变仪探究DACT和PLLD G₃的物质的量的比、交联浓度等因素对凝胶化行为的影响，最后通过体外抗菌实验探究水凝胶对大肠杆菌的抑制情况。实验结果表明，成功制备基于DACT和PLLD G₃的抗菌复合水凝胶。DACT的氧化度约为25％，粘均分子量约为16000；PLLD G₃理论分子量为1728，其实际分子量与理论分子量相接近。流变学实验表明，随着PLLD G₃的含量增加，复合水凝胶的交联密度增加，储能模量提高，力学强度增大。体外抗菌实验从定性和定量两个角度表明，复合水凝胶的抗菌活性优于对照组水凝胶。

关键词：醛基化壳聚糖 树枝状赖氨酸多肽 席夫碱键 抗菌

Construction and antibacterial activity of a polysaccharide-polypeptide Hydrogel

Abstract

2,3-di-aldehyde Chitosan（DACT）was prepared by oxidation of Chitosan. Three-generation polylysine dendrimer (PLLD G3) was prepared by divergent method, in which the amino group and aldehyde group of DACT formed the Schiff base bond, making contribution to the preparation of antibacterial composite hydrogel. The structures of DACT and PLLD G3 were characterized by FT-IR,¹H NMR and ESI-MS, and the oxidation degree and molecular weight of DACT were determined. The effects of the ratio of DACT and PLLD G3, the concentration of crosslinking and other factors on the gelation behavior were investigated by rheometer. The results showed that the antibacterial hydrogel based on DACT and PLLD G3 was successfully prepared. The oxidation degree of DACT is about 25％; the average molecular weight of DACT is about 16000; the theoretical molecular weight of PLLD G3 is 1728, which is close to the actual molecular weight. The rheological experiments show that with the increase of PLLD G3 content, the crosslinking density and storage modulus of the composite hydrogel both increases, resulting a better mechanical strength. The antibacterial activity of the Composite Hydrogel was better than that of the control group in both qualitative and quantitative aspects.

Key words：2,3-di-aldehyde Chitosan; polylysine dendrimer; Schiff base bond; antibacterial composite hydrogel

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1引言 1

1.2壳聚糖的性质及改性 1

1.2.1壳聚糖的理化性质 1

1.2.2高碘酸钠氧化壳聚糖 2

1.2.3 壳聚糖水凝胶敷料 3

1.3树状赖氨酸多肽 4

1.3.1 树状赖氨酸多肽的性质 4

1.3.2 树枝状多肽水凝胶 6

1.4 通过席夫碱键交联制备水凝胶 6

1.5 本课题的主要研究内容和意义 8

第二章 实验部分 10

2.1 醛基化壳聚糖的制备 10

2.1.1 实验原料 10

2.1.2 醛基化壳聚糖的合成步骤 10

2.1.3 醛基化壳聚糖分子量测试 10

2.1.4 醛基化壳聚糖氧化度测试 10

2.2 树状赖氨酸多肽的制备 10

2.2.1 实验原料 10

2.2.2 二代赖氨酸树状多肽（PLLD G₂）的制备 11

2.2.3 三代赖氨酸树状多肽（PLLD G₃）的制备 11

2.3 水凝胶的制备 11

2.4 实验仪器 12

第三章 结果与讨论 13

3.1 醛基化壳聚糖的分子量和氧化度 13

3.2 醛基化壳聚糖的结构表征 13

3.3 树状赖氨酸多肽的结构表征 14

3.4水凝胶的凝胶机理验证 14

3.5水凝胶的力学性能 15

3.6 水凝胶体外抗菌实验 15

第四章 总结与展望 17

4.1 结论 17

4.2展望 17

参考文献 19

本科期间发表论文 22

致谢 23

第一章 绪论

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