1：Experimental Design and Method Selection:

The study used an ex vivo Langendorff system to induce myocardial infarction in rat hearts, with NIR-II fluorescence imaging to visualize damaged tissues using Ag2S nanodots functionalized with angiotensin II peptide (ATII) or PEG. The rationale was to leverage the overexpression of AT1R receptors in damaged tissues for targeted imaging.

2：Sample Selection and Data Sources:

Sprague-Dawley rats (3 months old) were used, with hearts subjected to varying ischemia durations (15, 30, 45, 60 min) and reperfusion. Samples included myocardial tissues for Western blot analysis and hearts for imaging.

3：List of Experimental Equipment and Materials:

Ag2S-PEG and Ag2S-ATII nanodots (purchased from SINANO Int.), laser diodes (808 nm, Lumics and LIMO), InGaAs CCD cameras (Andor iDus DU490A and Xeva1.7-320), spectrometers (Andor Shamrock 193i and 163), optical filters (e.g., Thorlabs FEL850), dynamic light scattering equipment (Zetasizer Nano ZS, Malvern), Western blot apparatus (BioRad Molecular Imager ChemiDoc XRS System), Langendorff perfusion system, and various biochemical reagents.

4：7-320), spectrometers (Andor Shamrock 193i and 163), optical filters (e.g., Thorlabs FEL850), dynamic light scattering equipment (Zetasizer Nano ZS, Malvern), Western blot apparatus (BioRad Molecular Imager ChemiDoc XRS System), Langendorff perfusion system, and various biochemical reagents. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Hearts were cannulated and perfused with Krebs-Henseleit buffer; ischemia was induced by ligating coronary arteries or stopping perfusion; reperfusion was performed with nanodot solutions; fluorescence imaging was conducted with 808 nm excitation and NIR-II detection; Western blot was used to quantify AT1R protein levels.

5：Data Analysis Methods:

Fluorescence intensity and area were analyzed from images; statistical analysis included normalization and comparison of means; Western blot data were quantified by densitometry.