Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Central Campus, Navrangpura, Ahmedabad 380009, Gujarat, India.
Global Innovative Center for Advanced Nanomaterials (GICAN), Faculty of Engineering and Built Environment (FEBE), The University of Newcastle, Callaghan, New South Wales 2308, Australia.
J Colloid Interface Sci. 2020 May 1;567:154-164. doi: 10.1016/j.jcis.2020.01.099. Epub 2020 Jan 27.
An alarming increase in bacterial resistance towards various types of antibiotics makes it imperative to design alternate or combinational therapies to treat stubborn bacterial infections. In this perspective, emerging tools like nanozymes, nanomaterials with biological enzyme like characteristics, are being utilised to control infections caused by bacterial pathogens. Among several nanozymes used for antibacterial applications, FeO nanoparticles (NP) received great attention due to their effective peroxidase like activity. The pH dependent peroxidase activity of FeO NP results in generation of OH radical via the unique Fenton chemistry of iron. However, their pH dependent activity is restricted to acidic environment and dramatic loss in antibacterial activity is observed at near neutral pH. Here we describe a novel strategy to overcome the pH lacunae of citrate coated FeO NP by utilizing adenosine triphosphate disodium salt (ATP) as a synergistic agent to accelerate the OH radical production and restore its antibacterial activity over a wide range of pH. This synergistic combination (30 µg/mL FeO NP and 2.5 mM ATP) shows a high bactericidal activity against both gram positive (B. subtilis) and gram negative (E. coli) bacterial strains, in presence of HO, at neutral pH. The synergistic effect (FeO NP + ATP) is determined from the viability assessment and membrane damage studies and is further confirmed by comparing the concentration of generated OH radicals. Over all, this study illustrates ATP assisted and OH-mediated bactericidal activity of FeO nanozyme at near neutral pH.
各种类型的抗生素对细菌的耐药性令人震惊地增加，这使得设计替代或联合疗法来治疗顽固的细菌感染变得势在必行。在这方面，像纳米酶这样的新兴工具，即具有生物酶特性的纳米材料，正被用于控制由细菌病原体引起的感染。在用于抗菌应用的几种纳米酶中，由于其有效的过氧化物酶样活性，FeO 纳米颗粒（NP）受到了极大的关注。FeO NP 的 pH 依赖性过氧化物酶活性通过铁的独特 Fenton 化学导致 OH 自由基的生成。然而，它们的 pH 依赖性活性仅限于酸性环境，在接近中性 pH 时观察到抗菌活性显著丧失。在这里，我们描述了一种通过利用三磷酸腺苷二钠盐（ATP）作为协同剂来克服柠檬酸包覆的 FeO NP 的 pH 缺陷的新策略，以加速 OH 自由基的产生并在广泛的 pH 范围内恢复其抗菌活性。在中性 pH 下，这种协同组合（30 μg/mL FeO NP 和 2.5 mM ATP）在 HO 的存在下，对革兰氏阳性（枯草芽孢杆菌）和革兰氏阴性（大肠杆菌）细菌菌株均显示出高杀菌活性。协同效应（FeO NP + ATP）是通过存活率评估和膜损伤研究来确定的，并通过比较生成的 OH 自由基的浓度进一步得到证实。总的来说，这项研究说明了在接近中性 pH 时，FeO 纳米酶的 ATP 辅助和 OH 介导的杀菌活性。
