Nanomaterials with enzyme-like activity, generally referred to as ‘nanozymes’, find myriad potential in various biomedical fields. More importantly, the nanoparticles that can functionally mimic the activity of cellular antioxidant enzymes attract tremendous interest owing to their possible therapeutic candidature in oxidative stress-mediated disorders. Oxidative stress culminating due to excess reactive oxygen species (ROS) level and dysregulated cellular antioxidant machinery is implicated in the development and progression of various pathophysiological disorders such as cancer, diabetes, cardiovascular and neurodegenerative diseases. Moreover, the optimum essentiality of ROS due to its pivotal role in cell signaling evokes the requirement of novel artificial antioxidant enzymes that can circumvent the detrimental effects of enhanced ROS levels without perturbing the basal redox status of cells. In recent years, the fast emanating artificial enzymes, i.e. nanozymes with antioxidant enzyme-like activity, has made tremendous progress with their broad applications in therapeutics, diagnostic medicine, bio-sensing, and immunoassay. Among various antioxidant nanoparticles reported till-date, the metal oxide nanozymes have emerged as the most efficient and successful candidates in mimicking the activity of first-line defense antioxidant enzymes, i.e. superoxide dismutase, catalase, and glutathione peroxidase. This review intends to exclusively highlight the development of representative metal oxide-based antioxidant nanozymes capable of maintaining the cellular redox homeostasis and their potential therapeutic significance.

中文翻译：

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抗氧化金属氧化物纳米酶：在细胞氧化还原稳态和治疗中的作用

具有酶样活性的纳米材料，通常被称为“纳米酶”，在各种生物医学领域都有着巨大的潜力。更重要的是，可以在功能上模拟细胞抗氧化酶活性的纳米颗粒由于在氧化应激介导的疾病中可能的治疗候选资格而引起了极大的兴趣。由于过量的活性氧（ROS）水平和细胞抗氧化剂机制失调而导致的氧化应激最终与各种病理生理疾病（例如癌症，糖尿病，心血管疾病和神经退行性疾病）的发生和发展有关。而且，由于ROS在细胞信号转导中起关键作用，因此其最佳必要性引发了对新型人工抗氧化剂酶的需求，该酶可避免ROS水平升高的有害影响，而又不会干扰细胞的基础氧化还原状态。近年来，快速产生的人工酶，即具有抗氧化酶样活性的纳米酶，在其在治疗，诊断医学，生物传感和免疫测定中的广泛应用取得了巨大的进步。在迄今为止报道的各种抗氧化剂纳米颗粒中，金属氧化物纳米酶已成为模仿一线防御抗氧化剂酶（超氧化物歧化酶，过氧化氢酶和谷胱甘肽过氧化物酶）活性的最有效和成功的候选者。