Cytotoxic effects induced by unmodified and organically modified nanoclays in the human hepatic HepG2 cell line

Abstract

The term 'nanoclay' generically refers to the natural clay mineral, montmorillonite, with silica and alumina as the dominant constituents. The incorporation of nanoclays into polymeric systems dramatically enhances their barrier properties as well as their thermal and mechanical resistance. Consequently, nanoclays are employed in a wide range of industrial applications with recent studies reporting potential use in the modulation of drug release. With the increase in manufacturing of nanoclay-containing products, information on the toxicological and health effects of nanoclay exposure is warranted. Thus, the objective of the present study was to evaluate the cytotoxicity of two different nanoclays: the unmodified nanoclay, Cloisite Na+ ®, and the organically modified nanoclay, Cloisite 93A®, in human hepatoma HepG2 cells. Following 24 h exposure the nanoclays significantly decreased cell viability. Cloisite Na+ induced intracellular reactive oxygen species (ROS) formation which coincided with increased cell membrane damage, whilst ROS generation did not play a role in Cloisite 93A-induced cell death. Neither of the nanoclays induced caspase-3/7 activation. Moreover, in the cell culture medium the nanoclays aggregated differently and this appeared to have an effect on their mechanisms of toxicity. Taken together, our data demonstrate that nanoclays are highly cytotoxic and as a result pose a possible risk to human health.

Toxicological evaluation of clay minerals and derived nanocomposites: A review

“…In this sense, Cloisite s Na þ (CNa þ ) did not show signs of cytotoxicity in Caco-2 cells, although Cloisite s 30B (C30B) induced approximately 40% cytotoxicity at the highest concentration tested (226 mg/mL) after 24 h of exposure (Sharma et al, 2010). In addition, the cytotoxicity induced by CNa þ on HepG2 cells was lower than that obtained after exposure to Cloisite s 93A (C93A) for 24 h (Lordan et al, 2011). In addition, active bentonite, which is bentonite that is industrially treated with H 2 SO 4 , produced greater damage in human B lymphoblast cells than the native bentonite (Meibian et al, 2010).…”

Multi-functional coating of cellulose nanocrystals for flexible packaging applications

“…Therefore, considering also environmental problems, the interest in bio-39 based materials, such as poly lactic acid (PLA) (Vert et inevitable disadvantages that include a tendency to crack (Priolo et al, 2010) and 55 potential health risks (Lordan et al, 2011). Therefore, a sound strategy consists in 56 partially replacing conventional petrol-based plastics with bio-based materials, for 57 instance, utilizing bio-coatings with the two-fold aim of improving the original 58 plastic properties and reducing the plastic use.…”

Organically modified clays as binders of fumonisins in feedstocks

“…Han et al, [21] working on cells from different organs concluded that the toxicity of two organoclays on the viability and membrane damage was not severe. Contrasting results were obtained by Lordan et al [22] in experiments aimed to assess the cytotoxicity of a montmorillonite and an organically modified clay by measuring liver cells function and membrane integrity. Both materials were cytotoxic but the montmorillonite gave a worse performance than the modified clay in two of the three parameters attesting the cytotoxicity.…”