title: Cobalt Oxide Nanoparticles: Behavior towards Intact and Impaired Human Skin and Keratinocytes Toxicity.
abstract: Skin absorption and toxicity on keratinocytes of cobalt oxide nanoparticles (Co3O4NPs) have been investigated. Co3O4NPs are commonly used in industrial products and biomedicine. There is evidence that these nanoparticles can cause membrane damage and genotoxicity in vitro, but no data are available on their skin absorption and cytotoxicity on keratinocytes. Two independent 24 h in vitro experiments were performed using Franz diffusion cells, using intact (experiment 1) and needle-abraded human skin (experiment 2). Co3O4NPs at a concentration of 1000 mg/L in physiological solution were used as donor phase. Cobalt content was evaluated by Inductively Coupled-Mass Spectroscopy. Co permeation through the skin was demonstrated after 24 h only when damaged skin protocol was used (57 ± 38 ng·cm⁻²), while no significant differences were shown between blank cells (0.92 ± 0.03 ng cm⁻²) and those with intact skin (1.08 ± 0.20 ng·cm⁻²). To further investigate Co3O4NPs toxicity, human-derived HaCaT keratinocytes were exposed to Co3O4NPs and cytotoxicity evaluated by MTT, Alamarblue and propidium iodide (PI) uptake assays. The results indicate that a long exposure time (i.e., seven days) was necessary to induce a concentration-dependent cell viability reduction (EC50 values: 1.3 × 10-4 M, 95% CL = 0.8-1.9 × 10⁻⁴ M, MTT essay; 3.7 × 10⁻⁵ M, 95% CI = 2.2-6.1 × 10⁻⁵ M, AlamarBlue assay) that seems to be associated to necrotic events (EC50 value: 1.3 × 10⁻⁴ M, 95% CL = 0.9-1.9 × 10⁻⁴ M, PI assay). This study demonstrated that Co3O4NPs can penetrate only damaged skin and is cytotoxic for HaCat cells after long term exposure.
authors.affiliation: Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Via della Pietà, Trieste 19-34129, Italy. marcella.mauro82@gmail.com.
authors.forename: Marcella
authors.initials: M
authors.lastname: Mauro
authors.affiliation: Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Via della Pietà, Trieste 19-34129, Italy. gadami@units.it.|Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Giorgeri 2, Trieste 1-34127, Italy. gadami@units.it.
authors.forename: Matteo
authors.initials: M
authors.lastname: Crosera
authors.affiliation: Department of Life Sciences, University of Trieste, Via L. Giorgeri 7/9, Trieste 34127, Italy. mpelin@units.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Pelin
authors.affiliation: Department of Life Sciences, University of Trieste, Via L. Giorgeri 7/9, Trieste 34127, Italy. florio@units.it.
authors.forename: Chiara
authors.initials: C
authors.lastname: Florio
authors.affiliation: Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Via della Pietà, Trieste 19-34129, Italy. bellomo.francesca@gmail.com.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bellomo
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Giorgeri 2, Trieste 1-34127, Italy. gadami@units.it.
authors.forename: Gianpiero
authors.initials: G
authors.lastname: Adami
authors.affiliation: Dipartimento di Specialità Medico Chirurgiche, Scienze Radiologiche, Sanità Pubblica, University of Brescia, Piazza del Mercato, Brescia 15-25121, Italy. apostoli@med.unibs.it.
authors.forename: Piero
authors.initials: P
authors.lastname: Apostoli
authors.affiliation: Dipartimento di Specialità Medico Chirurgiche, Scienze Radiologiche, Sanità Pubblica, University of Brescia, Piazza del Mercato, Brescia 15-25121, Italy. giuseppe.depalma@unibs.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Palma
authors.affiliation: Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Via della Pietà, Trieste 19-34129, Italy. bovenzi@units.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bovenzi
authors.affiliation: IMEM-CNR Institute, Parco Area delle Scienze 37/A, Parma 43124, Italy. marco.campanini@imem.cnr.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Campanini
authors.affiliation: Clinical Unit of Occupational Medicine, Department of Medical Sciences, University of Trieste, Via della Pietà, Trieste 19-34129, Italy. larese@units.it.
authors.forename: Francesca Larese
authors.initials: FL
authors.lastname: Filon
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D003035:Cobalt / Q000633:toxicity*; D004249:DNA Damage; D004058:Diffusion; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000473:pathology; D053758:Nanoparticles / Q000633:toxicity*; D010087:Oxides / Q000633:toxicity*; D012867:Skin / Q000187:drug effects* / Q000473:pathology; D012869:Skin Absorption
chemical_list: D010087:Oxides; D003035:Cobalt; C060728:cobalt oxide
keywords: cobalt oxide; human skin absorption; in vitro; keratinocytes toxicity; nanoparticles