Cytotoxicity Evaluation of Modified Montmorillonites

HCEC-B4G12 (human corneal cell line) was obtained from Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH (DSMZ, Braunschweig, Germany) and cultured according to the recommended conditions. These cells were maintained in a complete medium, which consisted of 89% Dulbecco’s modified eagle medium, 10% FBS, and 1% penicillin/streptomycin. All cell cultures were incubated at 37 °C in a humidified environment with 5% CO₂. Next, the five types of Mt (Na-Mt, H-Na-Mt, C-H-Na-Mt, Ca-Mt, and MMt) were respectively dispersed in phosphate-buffered saline (PBS) to prepare stock solutions (50 mg/mL). The stock solutions were diluted to different concentrations within a culture medium containing 2% FBS and 1% penicillin/streptomycin, just before the cells’ treatment. The cells were adjusted to a concentration of 1 × 10⁵ cells/mL, in a volume of 100 μL per well in 96- well plates, for the below toxicity assays.