Selectively Antibacterial Silver-Gold Alloy Nanoparticles Conjugated with Target Specific Aptamer Sequences

与目标特异性适体序列缀合的选择性抗菌银金合金纳米粒子

• 批准号: 356685838
• 负责人: Professor Dr.-Ing. Stephan Barcikowski
• 金额: --
• 依托单位: Lehrstuhl für Technische Chemie I
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/356685838?language=en
• 关键词: Selectively; Antibacterial; Silver; Gold; Alloy

Implant- associated infections occur in many different medical disciplines and are one of the most important challenges in modern medicine. These infections are caused by bacteria organised in complex biofilms which are highly resistant to antibiotics and to the host's immune system. This can often lead to loss of the implant and - in some disciplines - even to life-threatening complications. Antibacterial implant surfaces and active substances have been used for prophylaxis or therapy. However, these have the disadvantage that bacterial cells cannot be selectively and effectively treated without causing long-term damage to human cells too. Consequently, there is great need for innovative anti-infective strategies with a broadened therapeutic window.In this project, targeting silver-gold alloy nanoparticles (AgAu-NP) with specific activity against selected pathogenic bacteria will be developed. This involves combining the properties of antibacterial but also cytotoxic Ag-NP and highly biocompatible Au-NP. Here silver is responsible for the bactericidal activity by Ag+ ion release, whereas gold is meant to increase particle stability, to control ion release and to allow conjugation with target-specific aptamers via gold-thiol chemistry. To this end stable AgAu-NPs are synthesised by using an advanced laser-based method, which allows synthesis of these alloy nanoparticles with controlled composition, while the resulting NPs are conjugated ex situ with thiolated aptamer sequences. In this context the influence of particle composition (AgAu) and particle size on metal ion release, surface coverage and conjugation efficiency during bioconjugation as well as the formation of soluble and insoluble silver species in different media will be systematically examined. Due to specific binding of these AgAu-NP-conjugates to the bacterial membrane of relevant bacteria like S. aureus and P. gingivalis the pathogens are exposed to a high local Ag+ concentrations found in the vicinity of the particles which selectively inhibits the growth of this bacterium, even in the presence of other strains. In order to deduce the ideal NP composition and to achieve maximal antibacterial activity combined with minimal toxicity, a variety of systematic molecular biological assays and cell culture tests will be performed. This includes co-culture models of different bacteria strains as well as of relevant bacteria parallel to human cells. Selective binding experiments will explore the possibility of a specific association of the AgAu-NP-conjugates to the bacteria, while, furthermore, cellular uptake is examined in order to elucidate the mechanism of bactericidal activity. The planned experiments provide a highly innovative procedure for the treatment of bacterial infections and will elucidate basic scientific knowledge on how bioconjugation is affected by NP composition.

植入体相关感染发生在许多不同的医学学科中，是现代医学中最重要的挑战之一。这些感染是由组织在复杂生物膜中的细菌引起的，这些细菌对抗生素和宿主的免疫系统具有高度耐药性。这通常会导致植入物的丢失，在某些学科中甚至会导致危及生命的并发症。抗菌种植体表面和活性物质已用于预防或治疗。然而，这些方法有一个缺点，即细菌细胞不能被选择性和有效地治疗，而不会对人类细胞造成长期损害。因此，非常需要具有拓宽治疗窗口的创新抗感染策略。本项目将开发针对特定致病菌具有特异性活性的靶向银金合金纳米颗粒（AgAu-NP）。这包括结合抗菌和细胞毒性Ag-NP和高度生物相容性Au-NP的特性。在这里，银通过银离子释放负责杀菌活性，而金的目的是增加颗粒稳定性，控制离子释放，并通过金-硫醇化学与目标特异性适配体结合。为此，稳定的AgAu-NPs通过一种先进的基于激光的方法合成，这种方法可以控制这些合金纳米颗粒的组成，而所得的NPs则与巯基适配体序列进行非原位共轭。在此背景下，颗粒组成（AgAu）和颗粒大小对金属离子释放、表面覆盖和生物偶联效率的影响，以及在不同介质中形成可溶性和不溶性银的影响将被系统地研究。由于这些agau - np偶联物与相关细菌（如金黄色葡萄球菌和牙龈卟啉卟啉菌）的细菌膜的特异性结合，病原体暴露于颗粒附近的高浓度局部Ag+，这选择性地抑制了这种细菌的生长，即使在其他菌株存在的情况下也是如此。为了推断出理想的NP组成并实现最大的抗菌活性和最小的毒性，将进行各种系统的分子生物学测定和细胞培养试验。这包括不同细菌菌株的共培养模型以及与人类细胞平行的相关细菌。选择性结合实验将探索agau - np偶联物与细菌特异性结合的可能性，同时，进一步研究细胞摄取以阐明杀菌活性的机制。计划中的实验为细菌感染的治疗提供了一个高度创新的过程，并将阐明关于NP组成如何影响生物偶联的基本科学知识。