Infinite m 200 monochromator based multifunction microplate reader

The in vitro cytotoxicity was measured by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HeLa cells. Cells were initially seeded into a 96-well cell culture plate at 1 × 10⁴ per well and then incubated for 24 h at 37°C under 5% CO₂. DEME solutions of nanovehicle at concentrations of 100 mg mL^-1 were added to the wells. The cells were further incubated for 72 h at 37°C under 5% CO₂. The cells were washed three times with 0.2 mL PBS to remove the unbound nanoparticles. Subsequently, 0.2 mL DEME and 25 mL MTT (5 mg mL^-1) were added to each well and incubated for an additional 4 h at 37°C under 5% CO₂. Then, the medium solution was replaced by 0.15 mL DMSO solution. After 10 min, the optical density at 490 nm (absorption value) of each well was measured on a Tecan Infinite M 200 monochromator-based multifunction microplate reader (Männedorf, Switzerland). The corresponding nanovehicle with cells but not treated by MTT were used as controls. The cell vitality after labeling was compared with that of unlabeled cells and expressed as the relative ratio.

Cell viability was quantitatively evaluated by methyl thiazolyl tetrazolium (MTT) assays. Briefly, the cells were planted into a 96-well cell culture plate at 5 × 10⁴ per well and were cultured at 37 °C and 5% CO₂ for 24 h. After that, the cells were treated with different conditions (including the incubation of DOX, TR-UCNS at different concentration, and laser irradiations under different power densities) and further cultured at 37 °C and 5% CO₂ for another 24 h. Then, MTT (5 μl, 5 mg ml⁻¹) was added to each well and the cells were incubated at 37 °C and 5% CO₂ for additional 4 h. A total of 50 μl of 10% SDS was added in each well and the plate was held at room temperature for 12 h. The optical density OD₅₇₀ value (Abs.) of each well, with background subtraction at 690 nm, was detected by a Tecan Infinite M200 monochromator-based multifunction microplate reader. Cell viability (%) was calculated using Eq. 2, which is given below: $$\mathrm{Cell}\mathrm{viability}\left(\%\right)=\left(\frac{\mathrm{Mean}\mathrm{of}\mathrm{Abs}.\mathrm{value}\mathrm{of}\mathrm{treatment}\mathrm{group}}{\mathrm{Mean}\mathrm{Abs}.\mathrm{value}\mathrm{of}\mathrm{control}}\right)100\%$$