2.8. Fluorescence microscopic examination
The morphological characterisation of HT-29 cells was performed
by using propidium iodide (PI) and acridine orange (AO)
double staining according to the method described by Ng et al.
(2013) and observed under a fluorescence microscope. Briefly,
HT-29 cells were plated at a density of 1 106 cells/ml in a
25 ml culture flask and treated with the IC50 concentration of
WTE determined from MTT assay at varying time points of incubation.
The cells were incubated in an atmosphere of 5% CO2 at 37 C
for 8, 12 and 24 h. Then the cells were harvested and washed twice
using PBS after centrifuging at 1800 rpm for 5 min to remove the
remaining media. An equal volume of fluorescent dye (AO/PI) containing
AO (10 lg/ml) and PI (10 lg/ml) were added to the cellular
pellet and freshly stained cells were observed under a UVfluorescence
microscope within 30 min before the fluorescence
colour started to fade.