Pelka Joanna, Gehrke Helge, Esselen Melanie, Türk Michael, Crone Marlene, Bräse Stefan, Muller Thierry, Blank Holger, Send Winfried, Zibat Volker, Brenner Patrice, Schneider Reinhard, Gerthsen Dagmar, Marko Doris
Institut für Angewandte Biowissenschaften, Abteilung für Lebensmitteltoxikologie, Universitt Karlsruhe (TH), Karlsruhe, Germany.
Chem Res Toxicol. 2009 Apr;22(4):649-59. doi: 10.1021/tx800354g.
Supercritical fluid reactive deposition was used for the deposition of highly dispersed platinum nanoparticles with controllable metal content and particle size distribution on beta-cyclodextrin. The average particle size and size distribution were steered by the precursor reduction conditions, resulting in particle preparations <20, <100, and >100 nm as characterized by transmission electron microscopy and scanning electron microscopy (SEM). These particle preparations of different size distributions were used to address the question as to whether metallic platinum particles are able to invade cells of the gastrointestinal tract as exemplified for the human colon carcinoma cell line HT29 and thus affect the cellular redox status and DNA integrity. Combined focused ion beam and SEM demonstrated that platinum nanoparticles were taken up into HT29 cells in their particulate form. The chemical composition of the particles within the cells was confirmed by energy-dispersive X-ray spectroscopy. The potential influence of platinum nanoparticles on cellular redoxsystems was determined in the DCF assay, on the translocation of Nrf-2 and by monitoring the intracellular glutathione (GSH) levels. The impact on DNA integrity was investigated by single cell gel electrophoresis (comet assay) including the formation of sites sensitive to formamidopyrimidine-DNA-glycosylase. Platinum nanoparticles were found to decrease the cellular GSH level and to impair DNA integrity with a maximal effect at 1 ng/cm(2). These effects were correlated with the particle size in an inverse manner and were enhanced with increasing incubation time but appeared not to be based on the formation of reactive oxygen species.
超临界流体反应沉积法用于在β-环糊精上沉积具有可控金属含量和粒径分布的高度分散的铂纳米颗粒。通过前驱体还原条件控制平均粒径和粒径分布，经透射电子显微镜和扫描电子显微镜（SEM）表征，得到粒径<20nm、<100nm和>100nm的颗粒制剂。这些不同粒径分布的颗粒制剂用于研究金属铂颗粒是否能够侵入胃肠道细胞，以人结肠癌细胞系HT29为例，从而影响细胞氧化还原状态和DNA完整性。聚焦离子束与SEM联用表明，铂纳米颗粒以颗粒形式被HT29细胞摄取。通过能量色散X射线光谱法确认了细胞内颗粒的化学成分。通过DCF检测、Nrf-2的转位以及监测细胞内谷胱甘肽（GSH）水平，确定了铂纳米颗粒对细胞氧化还原系统的潜在影响。通过单细胞凝胶电泳（彗星试验）研究了对DNA完整性的影响，包括对甲酰胺嘧啶-DNA-糖基化酶敏感位点的形成。发现铂纳米颗粒会降低细胞内GSH水平并损害DNA完整性，在1 ng/cm²时效果最大。这些效应与粒径呈反比关系，并随着孵育时间的增加而增强，但似乎不是基于活性氧的形成。
