CONICET | Buscador de Institutos y Recursos Humanos

Metal nanoparticles ?NPs? (10-100 nm) have an important antimicrobialactivity which suggests possible biomedical applications. Zinc NPs (ZnNPs) arewidely used for different products. The aim of this work was to investigate thetoxicity of ZnNPs biosynthesized by microorganisms, in a human keratinocyte cellline (HaCaT).ZnNPs were synthesized using Pseudomonasaeruginosa (ATCC 27853) and were characterized by UV-Vis spectroscopy andby transmission electron microscopy. HaCaT cells were incubated for 4 h and 24h at different ZnNPs dilutions (1/2, 1/5, 1/10). RPMI 1640 culture medium with5% FBS, a metal precursor salt solution of ZnSO4 (0.1 and 0.25 mM),and a bacterial growth control of biosynthesis (BGC), were used as controls.Cell viability was evaluated by MTT assay, crystal violet and neutral red tests;reactive oxygen species (ROS) were studied by DCF-DA; superoxide dismutase(SOD) activity was determined by riboflavin-NBT method; and reduced glutathione(GSH) by Ellman reactive. ZnNPs cell capture assays were performed byfluorescence microscopy and changes in cell migration were evaluated by woundhealing assay.As determined by fluorescence microscopy ZnNPs were able to enter HaCaTcells. The toxicity assays indicated that cell viability was significantlyaltered by ZnNPs 1/2 and BGC conditions after 4 h and 24 h incubation. ROSlevels increasedafter 4 h incubation with ZnNPs 1/2, 1/5, and BGC, while a 24 h incubation,1/10 dilution also augmented ROS. SOD activity increases at all ZnNPs dilutionstested, and with BGC. GSH was not modified by any treatment. Finally, thepresence of ZnNPs and BGC in the culture media affected cell migration.Altogether these results suggest that ZnNPs are able not only to enterinto skin cells but also to modify human keratinocyte viability,oxidant/antioxidant cell balance and cell migration. More studies are needed tounravel the mechanisms underlying these alterations.

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