Built-in Fluorescence Anisotropy: an in vivo Imaging Probe for bis-Retinoid Products in Retina

Abstract: Non-degradable fluorophores that accumulate as Lipofuscin in retinal pigment epithelium (RPE) cells has been a major source of intrinsic biomarker for quantifying the progression of several diseases, including age-related macular degeneration, Stargardt disease and, more. Recent progression in quantifying these diseases is entertained mostly by a few noninvasive imaging techniques, relied either on the life-time of the retinoid-fluorophores or, their linear and, non-linear absorption cross-sections. Apart from these intrinsic properties, a native, excited state dipole-dipole interaction mediated typical spectroscopic phenomenon that is excitation dependent emission-wavelength shifting is observed from these bis-retinoid fluorophores. Here, we emphasize the spectroscopic origin of this phenomenon and exploit one of its associated-properties, that is built-in fluorescence anisotropy as a noninvasive, in vivo imaging probe for bis-retinoid products in mouse eyes.