3.3. Cell Viability Assay

HUVEC viability was assessed by the MTT assay. The cells (5 × 10³ cells/well) were seeded in a 96-well plate with DMEM medium supplemented with 10% FBS. The culture medium was removed, and the cells were rinsed twice with PBS after the cells were allowed to adhere. HUVECs (5 × 10³ cells/well) were treated with fresh medium supplemented with 10% FBS and various concentrations of Ru (0, 1, 5, 10, 20, and 40 μM) at 37 °C for 48 h. After incubation, MTT solution (5 mg/mL) was added, and the plate was incubated for an additional 4 h. DMSO (100 μL) was added in each well, the resulting formazan deposit was solubilized in DMSO, and the optical density (OD) was recorded at 490 nm. All measurements were obtained in triplicate.