Intracellular ATP level measurement

An ATP kit was used to measure the intracellular ATP level. 4T1 cells were seeded at a density of 1 × 10⁵ cells per well in 6-well plates for 24 h at 37 °C. The cells were treated with FeCO-MnO₂@MSN at the concentration of 100 μg mL⁻¹. After 24 h, the cells were lysed and centrifuged. Thus, intracellular ATP can be obtained from the supernatant collected after lysis centrifugation. The firefly luciferase and fluorescein mixture was used as a probe for detecting ATP. Firefly luciferase catalyzes the fluorescein to produce fluorescence, requiring ATP to provide energy. When there is an excess of luciferase and fluorescein, the ATP concentration is linearly related to the fluorescence intensity. The ATP level was calculated according to the change of fluorescence intensity.