Three–Four Photon Transition Mn(II) Complex Monitoring Lysosome-Related ATP in Real Time <i>via</i> Fluorescence Lifetime Imaging

Abstract

Currently, in situ monitoring of the adenosine triphosphate (ATP) level in lysosomes is critical to understand their involvement in various biological processes, but it remains difficult due to the interferences of limited targeting and low resolution of fluorescent probes. Herein, we report a classic Mn(II) probe ( FX2-MnCl 2 ) with near-infrared (NIR) nonlinear (NLO) properties, accompanied by three–four photon transition and fivefold fluorescence enhancement in the presence of ATP. FX2-MnCl 2 combines with ATP through dual recognition sites of diethoxy and manganese ions to reflect slightly fluorescence lifetime change. Through the synergy of multiphoton fluorescence imaging (MP-FI) and multiphoton fluorescence lifetime imaging microscopy (MP-FLIM), it is further demonstrated that FX2-MnCl 2 displays lysosome-specific targeting behavior, which can monitor lysosome-related ATP migration under NIR laser light. This work provides a novel multiphoton transformation fluorescence complex, which might be a potential candidate as a simple and straightforward biomarker of lysosome ATP in vitro for clinical diagnosis.