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Journal of Toxicology
Volume 2013 (2013), Article ID 931785, 10 pages
http://dx.doi.org/10.1155/2013/931785
Research Article

In Vitro Toxicity Evaluation of Engineered Cadmium-Coated Silica Nanoparticles on Human Pulmonary Cells

1Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy
2Laboratory of Clinical Toxicology, IRCCS Maugeri Foundation, Medical Institute of Pavia, 27100 Pavia, Italy
3Department of Chemistry, University of Pavia, 27100 Pavia, Italy

Received 29 July 2013; Accepted 26 August 2013

Academic Editor: Michael Cunningham

Copyright © 2013 Uliana De Simone et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO2NPs (0.05–100 µg/mL) versus SiO2NPs and CdCl2 was evaluated by an in vitro test battery in A549 by assessing (i) mitochondrial function, (ii) membrane integrity/cell morphology, (iii) cell growth/proliferation, (iv) apoptotic pathway, (v) oxidative stress, after short- (24–48 h) and long-term (10 days) exposure. Both Cd-SiO2NPs and CdCl2 produced dose-dependent cytotoxic effects: (i) MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO2NPs pronounced effect than CdCl2. Cd-SiO2NPs induced mortality (about 50%) at 1 μg/mL, CdCl2 at 25 μg/mL; (ii) calcein-AM/PI staining: decrease in cell viability, noticeable at 25 μg/mL, enhanced markedly at 50 and 100 μg/mL, after 24 h. Cd-SiO2NPs induced higher mortality than CdCl2 (25% versus 4%, resp., at 25 μg/mL) with further exacerbation after 48h; (iii) clonogenic assay: exposure for longer period (10 days) compromised the A549 proliferative capacity at very low dose (0.05 μg/mL); (iv) a progressive activation of caspase-3 immunolabelling was detected already at 1 μg/mL; (v) GSH intracellular level was modified by all compounds. In summary, in vitro data demonstrated that both Cd-SiO2NPs and CdCl2 affected all investigated endpoints, more markedly after Cd-SiO2NPs, while SiO2NPs influenced GSH only.