磁性纳米多重抗菌复合材料的制备及性能研究

发布时间：2018-03-03 00:03

本文选题：环境友好　切入点：层层静电自组装　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着人民生活水平的不断提高,人们对健康生活环境的渴望也日益强烈。然而随着社会进步,人与人之间的接触和交流也越来越频繁,这也无形中为细菌的传播提供了便利,新型"超级细菌"也应运而生,传统的抗菌剂或抗菌材料已经难以发挥有效的作用。为应对各类细菌的挑战同时又满足人们对健康环保的要求,新型环境友好型强效抗菌材料的开发已经刻不容缓。本论文中,我们通过一种简便且绿色环保的方法—"层层静电自组装",以Fe_3O_4磁性纳米粒子为载体,在Fe_3O_4表面构建了聚阳电解质季铵化壳聚糖和聚阴电解质海藻酸钠抗菌多层膜。然后以聚电解质多层膜为模板,以抗坏血酸为还原剂将银离子原位还原成纳米银负载在多层膜上,制备得到了可回收的季铵化壳聚糖/纳米银型双重磁性纳米粒子抗菌复合材料(CG7@Ag)。并研究了不同组装条件和载银条件对制得的复合抗菌纳米材料的影响。具体研究过程如下:1、首先通过共沉淀法制备得到了磁性纳米粒子颗粒,然后通过聚丙烯酸的修饰使Fe_3O_4表面羧基化引入负电荷,再通过静电力的吸附作用依次吸附带异种电荷的聚电解质,构建多层抗菌膜。接着以抗坏血酸为还原剂还原吸附在多层膜上的银离子,生成纳米银。利用红外光谱(FT-IR)、热重分析(TG)、透射电镜(TEM)、Zeta电位和动态光散射粒径分析(DLS)对制备得到的双重抗菌复合材料的自组装过程,化学组成,表面形貌以及磁性等进行了全面系统的表征。通过电感耦合等离子质谱(ICP)对银离子释放过程进行了监测。以革兰氏阳性菌(S.aureus)和革兰氏阴性菌(E.coli)为样本,对双重磁性纳米粒子抗菌复合材料进行了一系列抗菌表征,包括"抑菌圈测试"、"抗菌动力学测试"和"循环抗菌测试"。抗菌结果显示,CG7@Ag双重抗菌复合粒子对S.aureus和E.coli都表现出快速有效的抗菌性能,且经过5轮循环抗菌后仍表现出较强的抗菌作用。2、探究了 Fe_3O_4表面羧基化过程中聚丙烯酸(PAA)的加入量;磁性纳米粒子分散液与聚电解质溶液加入的先后顺序;组装液浓度和组装时间这4个因素对静电自组装结果的影响。通过Zeta电位和动态光散射粒径分析(DLS)对组装过程进行跟踪和分析,最终确定了较佳的组装条件。3、通过透射电镜(TEM)观察载银过程中不同银离子浓度对负载的银纳米粒子尺寸的影响,并通过抑菌圈实验和抗菌动力学实验比较了不同载银粒径对最终制得的复合抗菌纳米材料抗菌性能的影响,结果发现负载的银纳米粒子的尺寸较小时,所制得的复合抗菌材料的抗菌性能越好。
[Abstract]:With the continuous improvement of people's living standards, people's desire for a healthy living environment has become increasingly strong. However, with the progress of society, contacts and exchanges between people have become more and more frequent, which has virtually facilitated the spread of bacteria. New "super bacteria" have emerged as the times require. Traditional antimicrobial agents or antimicrobial materials have been difficult to play an effective role. In order to meet the challenges of all kinds of bacteria and meet people's requirements for health and environmental protection, The development of new environment-friendly strong antibacterial materials is urgent. In this paper, we adopt a simple and green method, "layer by layer electrostatic self-assembly", using Fe_3O_4 magnetic nanoparticles as the carrier. Quaternary ammonium chitosan and sodium alginate polynegative electrolyte multilayers were constructed on the surface of Fe_3O_4, and then the polyelectrolyte multilayers were used as templates, and ascorbic acid was used as reducing agent to reduce silver ions in situ to nanoscale silver loaded on the multilayer films. The recoverable quaternary chitosan / nano-silver double magnetic nanoparticles antibacterial composite (CG7) was prepared. The effects of different assembling conditions and silver carrier conditions on the composite antibacterial nanomaterials were studied. The process is as follows: 1. First, magnetic nanoparticles were prepared by coprecipitation. Then the surface carboxylation of Fe_3O_4 was modified by polyacrylic acid to introduce negative charge, and then the polyelectrolyte with dissimilar charge was sequentially adsorbed by hydrostatic adsorption. A multilayer antibacterial film was constructed. Then ascorbic acid was used as reducing agent to reduce the silver ions adsorbed on the multilayer film. Nanocrystalline silver was produced. The self-assembly process and chemical composition of the prepared double antibacterial composites were studied by FTIR, TGX, TEM, TEM and DLSs. The surface morphology and magnetic properties were systematically characterized. The silver ion release process was monitored by inductively coupled plasma mass spectrometry (ICP). The samples of S. aureus and E.coli were Gram-positive bacteria and Gram-negative bacteria. A series of antimicrobial characterization of double magnetic nanoparticles antibacterial composite was carried out. These include "bacteriostasis test", "antimicrobial kinetic test" and "cyclic antibacterial test". The antibacterial results show that the double antibacterial composite particles of CG7 @ @ Ag exhibit rapid and effective antibacterial properties against S. aureus and E. coli. After 5 rounds of antibacterial cycle, it still showed strong antibacterial effect. 2. The addition amount of polyacrylic acid (PAA) in the carboxylation process of Fe_3O_4, the sequence of addition of magnetic nanoparticles dispersion and polyelectrolyte solution, and the order of addition of PAA and PAA in the process of carboxylation of Fe_3O_4 surface were investigated. The influence of the concentration of the solution and the assembly time on the electrostatic self-assembly results was studied. The assembly process was tracked and analyzed by Zeta potential and dynamic light scattering particle size analysis (DLS). Finally, the better assembly condition was determined. The effect of silver ion concentration on the size of silver nanoparticles was observed by TEM (TEM). The effects of different silver particle sizes on the antibacterial properties of the composite antibacterial nanomaterials were compared by the bacteriostasis test and the antibacterial kinetic experiment. The results showed that the size of the loaded silver nanoparticles was small. The antibacterial properties of the composite antibacterial materials are better.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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