3.11. Cytotoxicity Test by MTT Assay

The MTT assay was used to determine the effect of the peptide on the viability of MDCK cells [5,46]. The 96-well plates were used to culture the MDCK cells. After adding 10 μL of PBS containing MTT (0.5 mg/mL) into each well, the solution was incubated at 37 °C for 4 h. After removing the supernatant, 200 μL of DMSO was added into each well. The optical density (OD) for each well was determined at 570 nm. The IC₅₀ was calculated as the concentration of the sample at which the number of viable cells was decreased to 50% of that in the cell control.