Clinical Research Center for Hair and Skin Science, Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Berlin, Germany.
ACS Nano. 2012 Aug 28;6(8):6829-42. doi: 10.1021/nn301622h. Epub 2012 Jul 19.
In this study, the skin penetration and cellular uptake of amorphous silica particles with positive and negative surface charge and sizes ranging from 291 ± 9 to 42 ± 3 nm were investigated. Dynamic light scattering measurements and statistical analyses of transmission electron microscopy images were used to estimate the degree of particle aggregation, which was a key aspect to understanding the results of the in vitro cellular uptake experiments. Despite partial particle aggregation occurring after transfer in physiological media, particles were taken up by skin cells in a size-dependent manner. Functionalization of the particle surface with positively charged groups enhanced the in vitro cellular uptake. However, this positive effect was contrasted by the tendency of particles to form aggregates, leading to lower internalization ratios especially by primary skin cells. After topical application of nanoparticles on human skin explants with partially disrupted stratum corneum, only the 42 ± 3 nm particles were found to be associated with epidermal cells and especially dendritic cells, independent of their surface functionalization. Considering the wide use of nanomaterials in industries and the increasing interest for applications in pharmaceutics and cosmetics versus the large number of individuals with local or spread impairment of the skin barrier, e.g., patients with atopic dermatitis and chronic eczema, a careful dissection of nanoparticle-skin surface interactions is of high relevance to assess possible risks and potentials of intended and unintended particle exposure.
在这项研究中，研究了带正电荷和负电荷的不同尺寸（291 ± 9 至 42 ± 3nm）的无定形二氧化硅颗粒在皮肤中的渗透和细胞摄取。动态光散射测量和透射电子显微镜图像的统计分析用于估计颗粒聚集的程度，这是理解体外细胞摄取实验结果的关键方面。尽管在转移到生理介质后部分颗粒发生聚集，但颗粒仍以尺寸依赖的方式被皮肤细胞摄取。颗粒表面的功能化用带正电荷的基团增强了体外细胞摄取。然而，这种正效应与颗粒形成聚集的趋势形成对比，导致特别是原发性皮肤细胞的内化比率降低。在人体皮肤外植体上局部破坏角质层后，应用纳米颗粒后，只有 42 ± 3nm 的颗粒与表皮细胞，特别是树突状细胞相关，而与颗粒的表面功能化无关。考虑到纳米材料在工业中的广泛应用，以及在药物和化妆品中的应用兴趣日益增加，而皮肤屏障局部或广泛受损的个体数量众多，例如特应性皮炎和慢性湿疹患者，仔细剖析纳米颗粒与皮肤表面的相互作用对于评估预期和非预期颗粒暴露的潜在风险和潜力具有重要意义。
