Quenched coumarin derivatives as fluorescence lifetime phantoms for <scp>NADH</scp> and FAD

Abstract Two‐photon fluorescence lifetime imaging is a versatile laboratory technique in the field of biophotonics and its importance also growing vivo diagnostics for medical purposes. After years experience dermatology, endoscopic implementations are now posing new technical challenges. To develop, test, compare instrumental solutions this purpose suitable reference samples have been devised tested. These can serve as reliable NADH‐ FAD‐mimicking optical phantoms 2‐photon imaging, they be prepared relatively easily with reproducible stable characteristics quite relevant diagnostic technique. The (mixtures coumarin 1 6 ethanol amounts 4‐hydroxy‐TEMPO) tuned to exhibit spectral temporal very similar those NADH FAD, two molecules most frequently utilized characterize cell metabolism.