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.

种植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，这些生物膜对抗生素和宿主的免疫系统具有高度耐药性。这往往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。抗菌植入物表面和活性物质已被用于预防或治疗。然而，这些都有一个缺点，即细菌细胞不能在不对人类细胞造成长期损害的情况下得到选择性和有效的治疗。因此，迫切需要创新的抗感染策略，扩大治疗窗口。在本项目中，将开发靶向银金合金纳米颗粒(AgAU-NP)，该纳米颗粒具有对选定病原菌的特定活性。这涉及到结合抗菌但又具有细胞毒性的Ag-NP和高度生物相容性的Au-NP的特性。在这里，银通过释放银离子而起到杀菌活性，而金的作用是提高粒子稳定性，控制离子释放，并通过金-硫醇化学与靶标特异性适配子结合。为此，利用一种先进的基于激光的方法合成了稳定的AgAu-NPs，这种方法允许合成成分可控的合金纳米颗粒，同时得到的NPs与硫化适配子序列异位连接。在此背景下，系统地考察了粒子组成(AgAU)和粒子大小对金属离子释放、表面覆盖率和结合效率的影响，以及在不同介质中可溶和不溶银物种的形成。由于这些Agau-NP结合物与相关细菌如金黄色葡萄球菌和牙龈假单胞菌的细菌膜特异结合，病原体暴露在颗粒附近发现的高局部Ag+浓度下，即使在其他菌株存在的情况下，也选择性地抑制该细菌的生长。为了得到理想的NP组分，并达到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检测和细胞培养试验。这包括不同细菌菌株以及平行于人类细胞的相关细菌的共培养模型。选择性结合实验将探索AgAU-NP结合物与细菌发生特定结合的可能性，同时还将检测细胞摄取，以阐明杀菌活性的机制。计划中的实验为治疗细菌感染提供了一种高度创新的程序，并将阐明关于NP组成如何影响生物结合的基本科学知识。