二维碳纳米材料的抗菌性能探索

发布时间：2018-06-14 23:15

本文选题：抗药性 + 石墨烯　；参考：《中国科学技术大学》2016年博士论文

【摘要】：细菌抗药性的出现与扩散严重威胁全球公共卫生安全。发展新型抗菌药物是解决细菌抗药性的关键策略之一。石墨烯这种二维碳材料具有优越的物理性质和化学可修饰性,在生物医学领域具有良好的应用前景。本论文以氧化石墨烯类二维材料为研究对象,围绕它们的抗菌性能,从以下3个方面开展了一系列系统性的研究工作：一,揭示了导致氧化石墨烯的争议性抗菌性能的原因。有些文献报道称氧化石墨烯有广谱抗菌活性,而另一些则称氧化石墨烯没有抗菌活性、甚至对细菌生长有促进作用。那么氧化石墨烯是否具有抗菌活性、是什么原因导致它的抗菌性能具有争议?我们从建立有可比性的实验条件和实验方法着手,系统比较了在生理盐水与添加了少量细菌培养液的生理盐水(体积比≤10%)这两种条件下氧化石墨烯的抗菌活性,发现基面裸露的氧化石墨烯的确具有抗菌活性,但是其基面吸附某些培养液成分会导致不同程度失活。这种失活机制得到了采用胎牛血清白蛋白和色氨酸为模型吸附剂分子的类似实验的证实,而且也适用于解答氧化石墨烯对哺乳动物细胞到底有无毒性,显示氧化石墨烯的基面裸露程度决定其细胞毒性。二,以还原氧化石墨烯为光敏剂构建光控抗菌表面。光控抗菌表面具有可遥控性,但是当前光控抗菌表面基本都以半导体金属材料为光敏成分、因此只对紫外或者可见光具有响应性。与紫外可见光比,近红外光具有更大的组织穿透力和更小的组织伤害力。我们首次提出利用还原氧化石墨烯的近红外光热效应、构建光控抗菌表面。我们利用上述失活机制屏蔽了还原氧化石墨烯自身的抗菌性能,并通过层层自组装技术构建可抗菌表面,所得表面在避光条件下不具有抗菌活性、但在一个太阳光强照射下产生迅速局部升温并杀死90%的黏附其上的多种细菌(包含耐药菌)。进一步实验证实太阳光的近红外波段是导致上述抗菌性能的主要激发光,显示了这种光控抗菌表面在生物医学领域中具有应用前景。三,阐释了氧化石墨烯量子点的抗菌活性。石墨烯量子点有多种制备方式、对应也有多种来源材料。源于氧化石墨烯的氧化石墨烯量子点没有抗菌活性。与它不同,近期报道的源于富勒烯裂解碎片的氧化石墨烯量子点的碳原子同时具有六元环与五元环的排列方式。这种细节结构差异反映在抗菌性能上会导致何种相似与不同?我们以分别源于富勒烯裂解碎片的与源于有机小分子“自下而上”合成制得的氧化石墨烯量子点为研究对象,发现前者具有针对金黄色葡萄球菌的窄谱抗菌活性,而后者则与源于氧化石墨烯的氧化石墨烯量子点一样没有菌活性。进一步研究发现源于氧化石墨烯量子点可能通过黏附与细菌细胞表面并破坏其细胞壁与细胞膜的完整性导致细菌死亡,而氧化石墨烯量子点与目标细菌细胞的表面曲率是否匹配决定了氧化石墨烯量子点能否黏附于目标细菌细胞表面发挥后续抗菌作用。这个工作显示以目标细菌的形状大小为选择因子、定点清除目标细菌而不干扰其他细菌有望成为新型抗菌策略。
[Abstract]:The emergence and diffusion of bacterial resistance is a serious threat to global public health security. The development of new antimicrobial agents is one of the key strategies for the solution of bacterial resistance. The two dimensional carbon materials, such as graphene, have excellent physical properties and chemical modifiers, and have a good application prospect in the field of biomedicine. This paper is based on graphene oxide. A series of systematic studies have been carried out in the following 3 aspects: first, it reveals the cause of the controversial antibacterial properties that lead to graphene oxide. Some reports have reported that oxygen fossil Mexico has broad-spectrum antibacterial activity, while others say that graphene oxide has no antibacterial activity. It even promotes the growth of bacteria. Then, what is the reason for the antibacterial activity of graphene oxide is controversial? We have systematically compared the physiological saline with the addition of a small amount of bacterial culture (volume ratio less than 10%) from the establishment of experimental conditions and methods of comparison. The antibacterial activity of graphene oxide under two conditions was found. It was found that the exposed graphene oxide on the base surface did have antibacterial activity, but its base surface adsorbed some components of the medium to deactivate different degrees. This inactivation mechanism was confirmed by similar experiments with the use of fetal bovine serum albumin and tryptophan as a model adsorbent. It can also be used to solve the nontoxic effect of graphene oxide on mammalian cells. It shows that the exposure degree of the base surface of graphene oxide determines its cytotoxicity. Two, using the reduction of graphene oxide as a photosensitizer to construct a light controlled antibacterial surface. The surface of the light controlled antibacterial surface is remote-controlled, but the surface of the front photocontrolled antibacterial surface is basically semiconductor metal. As a photosensitive component, it is responsive only to UV or visible light. Compared with UV visible light, near infrared light has greater tissue penetration and smaller tissue damage. We first proposed the use of the near infrared photothermal effect of reduced graphene oxide to construct a light controlled antibacterial surface. The antibacterial properties of the original graphene oxide, and the antibacterial surface constructed by the layer self assembly technique, have no antibacterial activity on the surface, but the rapid local heating and killing 90% of the bacteria (including resistant bacteria) are produced under a solar light intensity. Further experiments confirm that the solar light is near. The infrared band is the main exciting luminescence that leads to the above antibacterial properties. It shows that the optically controlled antibacterial surface has a promising application in the biomedical field. Three, the antibacterial activity of the quantum dots of graphene oxide is explained. There are a variety of preparation methods for graphene quantum dots, and a variety of source materials. The graphene oxide is derived from graphene oxide. The quantum dots have no antibacterial activity. Unlike it, the recent reports that the carbon atoms of the graphene oxide quantum dots from the fullerene fragmentation fragment have simultaneous arrangement of six membered rings and five membered rings. What are the similarities and differences in the antibacterial properties of this detail structure? We are derived from the fragmentation fragments of fullerenes, respectively. The graphene oxide quantum dots, derived from the "bottom-up" synthesis of small organic molecules, have been found to have narrow antimicrobial activity against Staphylococcus aureus, and the latter has no bactericidal activity as the graphene oxide quantum dots originate from graphene oxide. The further study was found in the quantum dots of graphene oxide. The possibility of bacterial death by adhering to the surface of the cell and destroying the integrity of the cell wall and cell membrane, and whether the matching of the graphene oxide quantum dots and the surface curvature of the target bacterial cells determines whether the graphene oxide quantum dots can adhere to the following antibacterial action on the surface of the target bacterial cells. The size of the target bacteria is a selection factor. Targeted bacteria removal without interfering with other bacteria is expected to become a new antibacterial strategy.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R318.08;TQ127.11;TB383.1

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