Spectral measurements of fluorescence lifetimes for RPE lipofuscin with MM-fiber coupled SNSPD FLIM system
Pavel V.Morozov 1, 2, Vladislav Andreev 1,2,3, Marina Yakovleva 4,5, Tatiana Feldman 4,5, Anastasiya Ryabova 5, I. Romanishkin 5, and G.N.Goltsman1,2,3; 1Moscow Pedagogical State University, Moscow, Russia
2Superconducting Nanotechnology, Moscow, Russia; 3National University Higher School of Economics, Moscow, Russia; 3N.M. Emanuel Institute of Biochemical Physics RAS, Moscow, Russia; 4Lomonosov Moscow State University, Moscow, Russia; 5Prokhorov General Physics Institute, RAS, Moscow, Russia;
Abstract
The present work analyses the spectral dependence of the fluorescence lifetimes in lipofuscin granules. Measurements were performed using a confocal galvanometric laser scanner integrated with a large-active-area superconducting nanowire single-photon detector coupled to the standard multimode fiber (core diameter 50 μm). The object is a water solution suspension of lipofuscin granules (LGs) from retinal pigment epithelial (RPE) cells. LGs were photooxidized for 20 minutes using a 395 nm LED at a light density of 3 W/cm2 and were considered as a model of age-related macular degeneration (AMD). After exposure, changes were detected in the VIS-NIR fluorescence spectra as well as in the distribution of fluorescence lifetimes for LGs which were approximated by the three-exponential model. A notable increase in the mean fluorescence lifetimes τm for LGs was observed, rising from ~397 ps before irradiation to ~626 ps after it. A reciprocal spectral dependence of fluorescence lifetimes in LGs was discovered — with increasing of the registration wavelength from 500 to 800 nm the mean fluorescence lifetimes for component τm of LGs decrease from 580 ps to 195 ps for non-oxidized samples, and from 815 ps to 392 ps (registration wavelength range 500–800 nm) for photooxidized samples respectively.
Keywords— lipofuscin, FLIM, fluorescence lifetimes spectroscopy, A2E, bisretinoids, RPE, large area SSPD, decay curves, TCSPC
Speaker
Morozov Pavel
Moscow Pedagogical State University
Russia
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