The development of nanozymes, artificial enzymes made from inorganic nanoparticles, is widely studied due to their affordability, durability, and strength. Gold nanoparticles (AuNPs) are employed to imitate peroxidase, glucose oxidase, lactate oxidase, superoxide dismutase, and catalase. The last one transforms intracellular hydrogen peroxide into molecular oxygen, whose deficiency is characteristic of the hypoxic tumor microenvironment. Thus, gold nanoparticles are thought to enhance the overall effectiveness of photodynamic therapy. However, the enzyme-like activity of nanoparticles rapidly decreases in biological media, due to the aggregation and formation of the so-called “protein corona”. In this study, polymeric submicrocapsules loaded with AuNPs and a photodynamic dye are fabricated via Layer-by-Layer (LbL) assembly. The enhancement of photodynamic treatment efficacy by in situ production of oxygen by the catalase-like effect of AuNPs is investigated. Polymeric capsules are thoroughly characterized in terms of physicochemical and catalytic properties, and as a proof of concept, their therapeutic potential is evaluated in vitro. Furthermore, encapsulated AuNPs shows significantly lower aggregation both upon storage and during the reaction course. The results shows that the polymer capsules, containing AuNPs and photodynamic dye, show significantly higher light-induced cytotoxicity in comparison to the individual photodynamic dye, suggesting a synergistic effect between the formation of molecular oxygen by catalase-like gold nanozymes and photodynamic action.

中文翻译：

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封装在亚微米聚合物壳中的金纳米酶和光动力染料引起的光致毒性

纳米酶（由无机纳米粒子制成的人工酶）的开发因其经济性、耐用性和强度而受到广泛研究。金纳米粒子 (AuNP) 用于模拟过氧化物酶、葡萄糖氧化酶、乳酸氧化酶、超氧化物歧化酶和过氧化氢酶。最后一种将细胞内的过氧化氢转化为分子氧，分子氧的缺乏是缺氧肿瘤微环境的特征。因此，金纳米颗粒被认为可以增强光动力疗法的整体效果。然而，由于所谓的“蛋白冠”的聚集和形成，纳米颗粒的酶样活性在生物介质中迅速降低。在这项研究中，通过逐层 (LbL) 组装制备了负载 AuNP 和光动力染料的聚合物亚微胶囊。研究了通过 AuNP 的过氧化氢酶样效应原位产生氧气来增强光动力治疗效果。聚合物胶囊的物理化学和催化特性得到了彻底的表征，并且作为概念证明，它们的治疗潜力在体外进行了评估。此外，封装的金纳米粒子在储存和反应过程中都表现出明显较低的聚集。结果表明，与单独的光动力染料相比，含有AuNPs和光动力染料的聚合物胶囊表现出明显更高的光诱导细胞毒性，这表明过氧化氢酶样金纳米酶形成分子氧与光动力作用之间存在协同效应。