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

摘要

Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO_2NPs (0.05-100 mug/mL) versus SiO_2NPs and CdCl_2 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-SiO_2NPs and CdCl_2 produced dose-dependent cytotoxic effects: (i) MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO_2NPs pronounced effect than CdCl_2. Cd-SiO_2NPs induced mortality (about 50%) at 1 mug/mL, CdCl_2 at 25 mug/mL; (ii) calcein-AM/PI staining: decrease in cell viability, noticeable at 25 mug/mL, enhanced markedly at 50 and 100 mug/mL, after 24 h. Cd-SiO_2NPs induced higher mortality than CdCl_2 (25% versus 4%, resp., at 25 mug/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 mug/mL); (iv) a progressive activation of caspase-3 immunolabelling was detected already at 1 mug/mL; (v) GSH intracellular level was modified by all compounds. In summary, in vitro data demonstrated that both Cd-SiO_2NPs and CdCl_2 affected all investigated endpoints, more markedly after Cd-SiO_2NPs, while SiO_2NPs influenced GSH only.