1：Experimental Design and Method Selection:

The study involved designing and synthesizing a fluorescent probe based on imidazo[1,5-α]pyridine scaffold, utilizing excited-state intramolecular proton transfer (ESIPT) and photoinduced electron transfer (PET) processes for detection.

2：Sample Selection and Data Sources:

Human lung carcinoma cell lines (A549) were used for cytotoxicity assays and cell imaging. Hydrogen polysulfides were derived from Na2S2 prepared according to literature.

3：List of Experimental Equipment and Materials:

Instruments included UV-Vis spectrophotometer (Shimadzu UV-2550), spectrofluorometer (Edinburgh Instruments FS5), NMR spectrometer (Bruker ACF-300), mass spectrometer (Agilent 1100 Series LC/MSD, Mariner ESI-TOF), HPLC (Agilent 1260), confocal laser-scanning microscope (Zeiss LSM700), microplate reader (Tecan US), and pH meter (PB 10). Materials included chemicals from Bidepharm and KeyGEN BioTECH.

4：0). Materials included chemicals from Bidepharm and KeyGEN BioTECH. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis of NIPY-NF via esterification reaction; fluorometric analysis in PBS buffer with CTAB; cytotoxicity assay using MTT method; cell imaging with probe incubation and stimulation by Na2S2 or LPS; colocalization studies with LysoGreen.

5：Data Analysis Methods:

Fluorescence intensity measurements, linear regression for detection limit calculation, statistical analysis for cytotoxicity, and image analysis using ZEN and Image-Pro Plus software.