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人类最大的公共卫生问题之一。 21世纪。抗生素耐药细菌(ARB)导致超过280万人感染抗生素耐药 每年，超过3.5万人死于此病。抗生素耐药的主要途径 发育与内在细菌的能力有关，通过突变或改变 这些靶点或合成途径，改变或降解抗生素，或将抗生素泵出 手机。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)，这是在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传播给邻近的病原体。尽管付出了巨大的努力，但还是利用了广泛的 抗生素发现平台的一系列战略，他们的成功充其量是渐进式的。因此，有 迫切需要开发有效的方法来同时消除ARB和ARG。最近， 利用具有抗菌活性的纳米材料作为对抗ARB和ARGs的新选择已经被探索出来。 银纳米颗粒(AgNPs)作为抗菌剂具有广泛的应用前景。在……里面 此外，光动力灭活(PDI)也是消除ARB和ARGs的一种可行策略。令人瞩目的 AgNPs具有比表面积大、携带和释放Ag+离子的能力以及调节能力等特点 微生物流入/排出泵；和PDI喜欢高效地产生ROS，而不产生 进一步的耐药性使这些治疗方式成为ARB和ARGs失活的有希望的替代方案。 我们假设，通过将PDI和AgNPs这两种方法结合起来，在同一平台上产生协同效应 将实现消除ARB和销毁ARG。这个项目的主要目标是开发一种光激活的 银纳米粒子系统用于有效治疗ARB和ARGS。该项目由三个目标组成： 在目标1中，我们将合成并表征负载原卟啉IX(PpIX)的AgNPs。这一目标将证明 构建合理设计的AgNP平台将使PPIX的大有效载荷能够在稳定的情况下携带 表面性质可调的配方。对于目标2，我们将研究其化学稳定性和胶体稳定性。 不同培养基和光照射条件下的PPIX-AgNP材料。这一目标将提供关键 平台优化的信息和环境对RO产生的影响 和Ag+离子。最后，在目标3中，我们将研究PPIX-AgNPs对一组ARB的抗菌效果， 纳米颗粒在哺乳动物细胞中的降解动力学和细胞毒性。所获得的信息 这一目标将使我们能够将这一平台推向治疗应用。

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.