Aspect Ratio Dependent Cytotoxicity and Antimicrobial Properties of Nanoclay

Abstract

Nanoclays may enter human body through various routes such as through the respiratory and gastrointestinal tract, skin, blood, etc. There is dearth of such studies evaluating the interaction of clay nanoparticles with human cells. In particular, the interaction of proteins and nucleic acids with nanoparticles of different aspect ratio remains a domain that is very poorly probed and understood. In the present study, we address the issue of cytotoxicity and antimicrobial attributes of two distinct nanoclay platelets namely, laponite (diameter = 25 nm and thickness = 1 nm) and montmorillonite (MMT, diameter = 300 nm and thickness = 1 nm), having different aspect ratio (25:1 vs 300:1). Cytotoxicity was assessed in both prokatyotes: Escherichia coli, eukaryotes-human embryonic kidney (HEK), and cervical cancer SiHa cell lines, and a comparative size-based analysis of the toxicity were made at different exposure time points by MTT assay. The antimicrobial activity of the nanoclays was evaluated by disc diffusion method (Kirbey-Bauer protocol). Laponite exhibited maximum efficacy as an antimicrobial agent against E. coli. Comparatively smaller size laponite could preferentially enter the cells, leading to relatively wider or larger zone of inhibition. On contradictory; laponite showed 74.67 % survival while MMT showed 89.02 % survival in eukaryotic cells at 0.00001 % (w/v) concentration. In summary, both MMT and laponite indicated cytotoxicity at 0.05 % concentration within 24 h of exposure on HEK and cervical cancer (SiHa) cell lines. The toxicity was possibly dependent on size, aspect ratio, and concentration.

Biocompatible laponite ionogels based non-enzymatic oxalic acid sensor

“…Clays are used in biosensors as immobilization matrices due to their large specific surface area, good absorbance ability and high cationic exchange capacity [3][4][5][6]. Due to the property of laponite to form non-ergodic soft solids in the aqueous dispersions, they have been used to cast films onto electrodes for the immobilization of proteins [7][8][9][10][11] Rawat et al have studied the aspect ratio and concentration dependent cytotoxicity and antimicrobial activity of laponite and Montmorillonite nanoclay [12,13].…”

Comparison of the toxicity of aluminum oxide nanorods with different aspect ratio

“…However, it is very difficult to compare cytotoxicity results across studies, because the most part of data are not obtained in the context of the same experimental setup, thus presenting an issue in the interpretation of the results. In addition, properties of nanomaterials including size, shape, surface charge, and aspect ratio play a key factor depending toxicity of nanomaterials, and many researchers compared toxicity of nanomaterials, which have the different properties to define the characterization of biocompatible and biosafe nanomaterials (Almeida et al 2011;ling and Hyeon 2013;DeBrosse et al 2013;Rawat et al 2014;lin et al 2014). However, the most part of these studies are limited in vitro or in vivo.…”

3D printing of hydrogel composite systems: Recent advances in technology for tissue engineering

“…Nanoclays are classified into several classes such as Laponite, montmorillonite, bentonite, nontronite, saponite, kaolinite, hectorite, and halloysite by their geometrical shape and chemical composition which can affect biocompatibility. Rawat et al investigated the cytotoxicity and antimicrobial properties of various shape and concentration of nanoclays [100] . They prepared Laponite with an aspect ratio of 25:1 and montmorillonite (MMT) with an aspect ratio of 300:1, The cytotoxicity and antimicrobial properties of both nanoclays with various concentration from 0.00005 ug/mL to 0.0125 ug/mL were assessed by eukaryoteshuman embryonic kidney (HEK), and cervical cancer SiHa cell and Kirbey-Bauer protocol method, respectively.…”