Light-Activated Silver Nanoparticles to Eliminate Antibiotic Resistant Bacteria and Genes

摘要 微生物对抗菌剂耐药性的发展是当今世界最大的公共卫生问题之一。 21世纪世纪。抗生素耐药菌（ARB）在美国造成280多万例耐药感染。 美国每年有超过35,000人因此死亡。抗生素耐药的主要途径 发展与内在细菌的能力有关，通过突变迅速进化， 这些靶标或其合成途径改变或降解抗生素，或将抗生素泵出体外。 cell.此外，至关重要的是，所有这些耐药机制都是由抗生素编码的， 抗性基因（ARG），是DNA中编码的稳定分子，可以传递给子细胞 或通过水平基因转移转移到邻近的病原体。尽管做出了巨大的努力， 尽管有一系列抗生素发现平台战略，但它们的成功充其量只是渐进式的。因此有 迫切需要制定有效的方法，同时消除ARB和ARG。近日 已探索使用具有抗菌活性的纳米材料作为对抗ARB和ARG的新替代品。 银纳米颗粒（AgNPs）已被报道具有作为抗微生物剂的无数应用。在 此外，光动力灭活（PDI）也是消除ARB和ARG的可行策略。的显著 AgNP的特征，例如大的表面积、携带和释放Ag+离子的能力以及调节 微生物流入/流出泵;和PDI，如ROS的有效产生和不产生ROS的事实， 进一步的耐药性使这些治疗方式成为ARB和ARG失活的有希望的替代方案。 我们假设，通过将PDI和AgNP这两种方法结合在同一平台上， 消除ARB和销毁ARG的目标将得以实现。该项目的主要目标是开发一种光激活的 银纳米颗粒系统用于有效治疗ARB和ARG。该项目包括三个目标： 在目标1中，我们将合成和表征负载原卟啉IX（PpIX）的AgNPs。这一目标将证明 制造一个合理设计的AgNP平台将使大量有效载荷的PpIX能够在稳定的 具有可调表面性质的配方。对于目标2，我们将研究以下物质的化学和胶体稳定性： PpIX-AgNP材料在不同的培养基和光照条件下。这一目标将提供关键 用于优化平台的信息以及环境对ROS生成的影响 和Ag+离子。最后，在目标3中，我们将研究PpIX-AgNP对一组ARB的抗微生物功效， ARGs降解动力学和纳米颗粒在哺乳动物细胞中的细胞毒性。获得的信息 这一目标将使我们能够将这个平台推向治疗应用。

Abstract The development of microbial resistance to antimicrobial agents is one of the biggest public health issues of the 21st century. Antibiotic-resistant bacteria (ARB) cause more than 2.8 million antibiotic-resistant infections in the U.S. each year, and more than 35,000 people die as a result. The principal ways of antibiotic resistance development are related to the intrinsic bacteria’s ability to evolve rapidly through mutations to either modify these targets or the pathways for their synthesis, alter or degrade the antibiotic, or pump the antibiotic out of the cell. Moreover, of critical importance is that all of these resistance mechanisms are encoded by antibiotic resistance genes (ARGs), which are stable molecules encoded in the DNA and can be passed to daughter cells or transported by horizontal gene transfer to neighboring pathogens. Despite tremendous efforts utilizing a wide range of antibiotic discovery platform strategies, their success has been at best incremental. Therefore, there is a critical need to develop effective approaches to simultaneously eliminate both ARB and ARGs. Recently, the use of nanomaterials with antimicrobial activity has been explored as a new alternative against ARB and ARGs. Silver nanoparticles (AgNPs) have been reported to have myriad applications as antimicrobial agents. In addition, photodynamic inactivation (PDI) is also a feasible strategy to eliminate ARB and ARGs. The remarkable features of AgNPs such as large surface area, capability to carry and release Ag+ ions, and ability to modulate the microbial influx/efflux pumps; and PDI like efficient generation of ROS and the fact that does not generate further resistance make these treatment modalities a promising alternative for the inactivation of ARB and ARGs. We hypothesize that by combining both approaches, PDI and AgNPs, in the same platform a synergistic effect to eliminate ARB and destroy ARGs will be achieved. The main goal of this project is to develop a light-activated silver nanoparticulate system for the effective treatment of ARB and ARGs. This project consists of three aims: in Aim 1, we will synthesize and characterize protoporphyrin IX (PpIX)-loaded AgNPs. This aim will demonstrate that fabricating a rationally designed AgNP platform will enable a large payload of PpIX to be carried in a stable formulation with tunable surface properties. For Aim 2, we will investigate the chemical and colloidal stability of PpIX-AgNP materials under different culture medium and light irradiation conditions. This aim will provide key information for the optimization of the platform and the influence of the environment on the generation of ROS and Ag+ ions. Finally, in Aim 3, we will study the antimicrobial efficacy of PpIX-AgNPs against a panel of ARB, the ARGs degradation kinetics and the nanoparticles cytotoxicity in mammalian cells. The information obtained in this aim will allow us to move forward this platform to therapeutic applications.