Victor x3 uv vis spectrophotometer

Cell metabolic activity of hCMEC/D3 and HBVP cell lines upon treatment with magnetic nanocapsules was assessed by the WST-1 assay, as previously described [27] . The metabolic activity of cells was assessed at 24 and 72 h after the administration of the magnetic nanocapsules. Briefly, 10 4 cells/cm 2 were seeded in 48 well-plates. After overnight incubation, cells were treated with different concentrations of magnetic nanocapsules (10, 50, 100, 300 and 500 µg/mL), whereas untreated cells were used as a control. After 24 and 72 h of incubation, treatments were removed, and cells were incubated with 300 µL of WST-1 reagent diluted (1:20) in complete DMEM without phenol red (Gibco) at 37ºC for 40 min (hCMEC/ D3) or 2 h (HBVP) due to their different metabolic rates. Thereafter, absorbance was measured at 450 nm using a Perkin Elmer Victor X3 UV-Vis spectrophotometer. The absorbance of the blank (WST-1 1:20 dilution in phenol red-free DMEM) was subtracted from all measurements. The data were expressed as % of cell metabolic activity with respect to untreated controls. All WST-1 assays were performed in triplicate.