1：Experimental Design and Method Selection:

The probe Mito-NRT-HP was designed based on a naphthalimide derivative with a triphenylphosphonium group for mitochondrial targeting and a 2-fluoro-5-nitrobenzoate moiety as the receptor for H2Sn. The sensing mechanism involves H2Sn-induced nucleophilic substitution and intramolecular cyclization, leading to a ratiometric fluorescence response.

2：Sample Selection and Data Sources:

HeLa and BHK cells were used for in vitro imaging. Tissue samples from LPS-induced acute organ injury model mice (intestine, lung, liver, kidney, spleen) were used for ex vivo imaging.

3：List of Experimental Equipment and Materials:

Instruments included JNM-ECS 400M NMR spectrometer, Bruker Esquire 6000 Ion Trap System for ESI-MS, Edinburgh Instrument FLS920 spectrophotometer for quantum yield and two-photon fluorescence, Varian Cary 5000 UV-Vis-NIR spectrophotometer, Hitachi F-7000 spectrophotometer, Leica TCS SP8 confocal microscope, Olympus FV1000 MPE two-photon microscope. Reagents included various chemicals from commercial sources, Mito Tracker Red CMXRos, Lyso Tracker Red DND-99, CellTiter 96? AQueous One Solution Cell Proliferation Assay.

4：Experimental Procedures and Operational Workflow:

Synthesis of Mito-NRT-HP involved multi-step organic synthesis. Spectroscopy studies were performed in PBS buffer. Cell culture and imaging involved incubating cells with the probe and various treatments (e.g., Na2S2, NMM, LPS, L-Cys). For in vivo application, mice were injected with LPS or saline, then with Mito-NRT-HP, and tissues were harvested for imaging.

5：Data Analysis Methods:

Fluorescence spectra were analyzed for intensity ratios (I546 nm/I478 nm, I470 nm/I532 nm). Two-photon absorption cross sections were measured using fluorescein as a reference. Cell viability was assessed using MTS assay. Colocalization analysis was performed using fluorescence intensity profiles and scatter plots.