Abstract Natural antioxidants, such as epigallocatechin-3-gallate and related phenolic compounds from tea, enhance particle cell-interactions and cellular uptake. In this study, surface of superparamagnetic iron oxide nanoparticles prepared by co-precipitation of Fe chlorides was modified with silica, polyethylenimine, poly(ethylene glycol), and poly( l -lysine) to protect the iron oxide core from redox-reactions with phenols, enhance uptake by the cells, prevent the particle aggregation, or enable conjugation with several phenol-based antioxidants. To reveal the relation between the particle uptake and chemical structure of the phenolic antioxidants, five of them were selected, namely phenol, phloroglucinol, chlorogenic, gallic, and tannic acid. After incubation of the phenol-modified nanoparticles with U87MG human glioma cells, intracellular levels of the reactive oxygen species were reduced in a similar manner, as measured by flow cytometry. Colorimetric iron assay revealed a comparable level of cell-associated particles, which was mostly independent on the applied external magnetic field. The results suggest that the poly( l -lysine)-based coating is responsible for the antioxidant effects of the particles; the phenol- and poly( l -lysine)-coatings enable effective colloidal stability in aqueous media and enhance cellular internalization of the nanoparticles.

中文翻译：

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抗氧化聚合物改性磁赤铁矿纳米粒子

摘要 天然抗氧化剂，例如来自茶的表没食子儿茶素-3-没食子酸酯和相关酚类化合物，可增强颗粒细胞相互作用和细胞摄取。在这项研究中，通过共沉淀氯化铁制备的超顺磁性氧化铁纳米粒子的表面用二氧化硅、聚乙烯亚胺、聚（乙二醇）和聚（l-赖氨酸）改性，以保护氧化铁核免受酚类的氧化还原反应，增强细胞吸收，防止颗粒聚集，或与几种酚类抗氧化剂结合。为了揭示酚类抗氧化剂的颗粒吸收和化学结构之间的关系，选择了其中五种，即苯酚、间苯三酚、绿原、没食子和单宁酸。苯酚修饰的纳米粒子与 U87MG 人脑胶质瘤细胞孵育后，通过流式细胞术测量，细胞内活性氧的水平以类似的方式降低。比色铁测定揭示了相当水平的细胞相关颗粒，这主要与施加的外部磁场无关。结果表明，基于聚（l-赖氨酸）的涂层负责颗粒的抗氧化作用；酚-和聚（l-赖氨酸）-涂层能够在水性介质中实现有效的胶体稳定性，并增强纳米颗粒的细胞内化。结果表明，基于聚（l-赖氨酸）的涂层负责颗粒的抗氧化作用；酚-和聚（l-赖氨酸）-涂层能够在水性介质中实现有效的胶体稳定性，并增强纳米颗粒的细胞内化。结果表明，基于聚（l-赖氨酸）的涂层负责颗粒的抗氧化作用；酚-和聚（l-赖氨酸）-涂层能够在水性介质中实现有效的胶体稳定性，并增强纳米颗粒的细胞内化。