Fluorescence lifetime microscope for corneal metabolic imaging

Abstract

Assessing corneal metabolism may provide clinicians a tool for diagnosing corneal cells dysfunctions prior to its pathological expression. Flavin adenine dinucleotide (FAD), a metabolic co-factor, exhibits two lifetime components (long and short) upon blue light excitation. Due to that, fluorescence lifetime imaging microscopy (FLIM) may provide a method to evaluate corneal cells metabolism non-invasively. We are developing a single-photon, time-gated fluorescence lifetime microscope for in vivo corneal imaging using structured illumination to improve optical sectioning. Single-photon imaging is provided by a picosecond diode laser with emission at 443nm. Structured illumination is implemented by modulating the laser light through a Digital Micromirror Device (DMD). The fluorescence imaging acquisition is based on an ultrafast time-gated intensified CCD camera operating with gates down to 200ps. We present preliminary data regarding the timing and optical performance of the microscope.