Fig. 3
From: In vivo imaging of endogenous enzyme activities using luminescent 1,2-dioxetane compounds
CIEEL energy transfer imaging of enzyme activities in cells. a Chemical structures and optical properties of three membrane-targeting fluorescent dialkylcarboncyanines, DiI, DiD, and DiR. The blue shaded region indicates the self-decomposition light emission of Galacton-plus. b Human HCT116/LacZ colon cancer cells were single-stained with DiI, DiD, DIR or double-stained with both DiD and DiR prior to CIEEL imaging with Glalacton-plus. The cells were stably transfected with a LacZ construct for bacterial β-galactosidase expression and Galacton-plus activation. The total luminescence emission was imaged without an emission filter (open), and then scanned from 500 to 680 nm. Fluorescence imaging was also performed to determine the input levels of dyes. The DiD + DiR double-stained cells contained half fluorescence intensity for each dye in comparison with the corresponding single-stained cells. c Quantitative representation of the luminescence emission profiles as in b