Evaluating EGCG Hydrogel Lens Cytotoxicity

The cytotoxicity of EGCG loaded starch hydrogel/contact lens composites was evaluated based on the effects of contact lenses extracts on the proliferation of human corneal epithelial cells (HCECs, Seoul, Korea) through cell counting kit-8 (CCK-8) assay. 2.5 and 5 mg of different type contact lenses were respectively dipped in 10 ml DMEM/F12 (Sigma-Aldrich) containing 10% (v/v) fetal bovine serum (Sigma-Aldrich) and 1% (v/v) antibiotic/antimycotics (Sigma-Aldrich) in 37°C, 5% CO₂ incubator for 24 h to obtain contact lenses extracts with concentrations of 1:4 and 1:2 (Li et al., 2020 (link)). While the HCECs were plated into a 96-well plate at 2000/well and cultured in standard culture medium (DMEM/F12, 10% FBS, 1% antibiotic/antimycotics) for 24 h in 37°C, 5% CO₂ incubator. Then, the culture medium of all the wells was taken out and different group cells were cultured with the prepared contact lens extracts along with fresh standard culture medium, respectively. After culturing in 37°C, 5% CO₂ incubator for 1, 3, 5 and 7 days, CCK-8 detection reagent (Dojindo Laboratories Kumamoto, Japan) was added to measure the absorbance of the cells at 450 nm wavelength with SpectraMax M2 (Molecular Devices, United States).