Autofluorescence Lifetime Imaging of Retinal Pigment Epithelium Cells Using Two-photon Excitation

In this paper, we demonstrate that two-photon excitation fluorescence lifetime imaging can provide critical morphological information of the retinal pigment epithelium (RPE) cells and facilitate accurate differentiation of the endogenous fluorophores in RPE cells at subcellular level via time-resolved autofluorescence measurement. Morphological and lifetime analysis show that there are two lifetime components in the RPE cells, whose lifetimes are about 620 ps and 1.4 ns respectively. Our results also reveal the spatial distribution and components of the fluorophores in the RPE cells. Combined with a laser scanning confocal ophthalmoscope, two-photon excitation fluorescence lifetime imaging might provide a novel instrumentation for the clinical diagnosis and pathological studies of age related eye diseases.