MC-PSE

Guidelines (The following is a recommended experimental protocol for guidance only, and should be adjusted according to your specific requirements)
1. Stock Solution Preparation
1.1 Solvents: DMSO; buffer solution (alternative).
1.2 Concentration recommendation: A high-concentration stock solution of 1-10 mM is generally recommended.
2. Working Solution Preparation
2.1 Diluents: DPBS/DMSO (v/v = 7:3, pH 7.4); PBS/DMSO (v/v = 7:3).
2.2 Working concentrations: 10 μM for in vitro fluorescence and photoacoustic experiments; 200 μM for in vivo intratumoral injection.
2.3 Notes: The working solution concentration can be adjusted as needed; prepare and use immediately.
3. Staining Procedures
3.1 Description of sample types
3.1.1 In vitro aqueous solution samples (photophysical property/selectivity test)^[1]:
3.1.2 In vivo subcutaneous tumor-bearing mouse models/tumor-bearing animal samples^[1]: Intratumoral and normal tissue injection sites.
3.2 Incubation conditions
3.2.1 In vitro aqueous solution samples^[1]: Incubate 10 μM MC-PSE with GSH (L-Glutathione reduced) (HY-D0187) (0-140 μM) for up to 15 min for fluorescence response testing; incubate 10 μM MC-PSE with 100 μM GSH or interfering substances for selectivity testing.
3.2.2 In vivo subcutaneous tumor-bearing mouse models/tumor-bearing animal samples^[1]: Inject 200 μM MC-PSE (20 μL) into intratumoral and normal tissue sites; perform imaging at 5, 10, 20, 40, and 60 min after injection (fluorescence intensity reaches its peak at approximately 20 min). For inhibition studies, inject NEM 30 min prior to MC-PSE injection. Fluorescence enhancement at 940 nm is triggered via reaction with glutathione (GSH).
3.3 Washing step: Omitted.
4. Control Setup
4.1 Set up negative controls, positive controls, and blank controls:
4.1.1 Negative control: Incubate MC-PSE with physiological concentrations of non-GSH biological thiols (Cys, Hcy), common ions, or ROS/RNS; pre-treat in vivo sites with NEM to deplete GSH.
4.1.2 Blank control: Tissue regions in mouse models without reagent injection.
4.1.3 Positive control: Incubate MC-PSE with 100 μM GSH in in vitro experiments; tumor sites without NEM pre-treatment in in vivo experiments.
4.2 Positive controls are used to validate the experimental system; blank controls are used to exclude interference from the inherent fluorescence of reagents.
5. Detection and Analysis
5.1 Instrument types: NIR-II fluorescence imager; photoacoustic imager.
5.2 Excitation/emission wavelengths
5.2.1 Fluorescence: Ex = 808 nm, Em = 940 nm (NIR-II window); an 1100 nm long-pass filter is required for in vivo imaging.
5.2.2 Photoacoustic: Detect wavelengths at 900 nm and 980 nm for ratiometric analysis.
5.3 Result analysis
5.3.1 Changes in fluorescence intensity: After reaction with GSH, the NIR-II fluorescence intensity at 940 nm increases by up to 20-fold; the tumor region shows time-dependent fluorescence enhancement, with a signal-to-background ratio (SBR) up to 4.2-fold higher than that of normal tissue. Activated NIR-II fluorescence is observable after reaction with GSH.
5.3.2 Changes in photoacoustic signals: In GSH-rich regions, the PA intensity at 980 nm decreases significantly, while the PA intensity at 900 nm remains stable; the PA₉₀₀/PA₉₈₈ ratio increases by up to 4-fold in in vitro experiments, and the ratio in tumor tissue is 2-fold higher than that in normal tissue in in vivo experiments.
5.3.3 Localization and differentiation: Fluorescence signals localize to tumor regions; NIR-II fluorescence and ratiometric photoacoustic dual-modal imaging can be used to distinguish normal tissue from tumor tissue in tumor-bearing mice.
5.3.4 Control group results: Fluorescence and PA signal changes are minimal in sites pre-treated with NEM; non-GSH interfering substances do not cause significant changes in fluorescence or PA ratios.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.