Differential toxicity of copper (II) oxide nanoparticles of similar hydrodynamic diameter on human differentiated intestinal Caco-2 cell monolayers is correlated in part to copper release and shape

Abstract

The potential toxic effects of copper oxide (CuO) nanoparticles (NPs) were studied on differentiated Caco-2 cell monolayers, a classical in vitro model of human small intestine epithelium. Two types of CuO NPs, with different specific surface area, different sizes as raw material but the same hydrodynamic diameter in suspension, differentially disturbed the monolayer integrity, were cytotoxic and triggered an increase of the abundance of several transcripts coding for pro-inflammatory cytokines and chemokines. Specific surface area was not a major variable explaining the increased toxicity when intestinal epithelium is exposed to rod-shaped CuO NPs, compared with spherical CuO NPs. The results suggest that release of Cu(II) cations and shape of these CuO NPs are likely to be implicated in the toxicity of these CuO NPs.

Dissolution and aggregation of Cu nanoparticles in culture media: effects of incubation temperature and particles size

“…In general, copper-containing NPs show a size-and species-dependent toxicity to organisms (Di Bucchianico et al 2013;Piret et al 2012). For instance, Chen et al (2006) found that CuNPs could induce more severely pathological injuries to the kidney, liver, and spleen of mice compared to copper at micrometer size.…”

A guide to nanosafety testing: Considerations on cytotoxicity testing in different cell models

“…These cells can undergo enterocytic differentiation (Jumarie and Malo 1991;Piret et al 2012) and represent the gastro-intestinal tract in this study. THP-1 cells are monocytes derived from human, male, acute monocytic leukaemia, and can be differentiated into macrophage-like cells (Chanput et al 2014).…”

“…To obtain a tight intestinal epithelium, Caco-2 cells were differentiated as described previously (Piret et al 2012). Briefly, 50,000 Caco-2 cells were grown on transwell polycarbonate filters (12 wells, pore diameter of 3 µm, 1.12 cm 2 growth area, Corning Costar) for 16 days.…”

“…BC was used at as positive control (Piret et al 2012) to verify the performance of the assays (Supplemental Table 2). In addition, TEER was measured on differentiated Caco-2 cells to evaluate the effect of NPs on the intestinal epithelium integrity.…”

“…Benzalkonium chloride (BC, Sigma-Aldrich), known to induce cell death in multi-layered engineered tissues like RHE and in differentiated Caco-2 monolayers was used as positive control (Supplemental Table 2) (Coquette et al 2003;Piret et al 2012;Vankoningsloo et al 2010). Zinc sulphate (Sigma-Aldrich) and Triton X-100 were used as positive chemical control for CD34-DCs or A549/THP-1 cells respectively (Supplemental Table 2).…”