MB-m-borate 

MB-m-borate is a double-locked near-infrared fluorescence-activated probe (Ex/Em ≈ 647 nm/684 nm). MB-m-borate undergoes cascade activation by hydrogen peroxide and tyrosinase to release the fluorophore methylene blue, thereby generating a fluorescence activation response. MB-m-borate enables precise detection of melanoma in melanoma cells and mouse models. MB-m-borate can be used for melanoma research^[1].

MB-m-borate (20 μM; 2 h) generates strong and selective fluorescence in human melanoma A375 cells, while producing extremely low signals in non-melanoma cell lines and normal melanocyte lines. Moreover, the generation of this fluorescence depends on the activity of H₂O₂ and TYR^[1].

Guidelines (The following is our recommended protocol, which serves only as a guide and should be modified according to your specific needs).
1. Reagent Preparation: Prepare MB-m-borate stock solution (dissolved in DMSO), and dilute it to 20 μM with cell culture medium or PBS immediately before use.
Tyrosinase inhibitor: Kojic acid (HY-W050154) (200 μM)
ROS scavenger/antioxidant: N-acetyl-L-cysteine (HY-B0215) (NAC) (200 μM)
2. Experimental Procedure:
2.1 Cell Seeding: Seed target cells (e.g., human melanoma A375 cells) into 3.5 cm confocal dishes and culture them to an appropriate density.
2.2 (Optional) Inhibitor Pretreatment: To verify specificity, pretreat cells with culture medium containing 200 μM Kojic acid or NAC for 2 hours.
2.3 Probe Incubation:
Add 20 μM MB-m-borate working solution (if inhibitors are used, they must be present in the incubation solution simultaneously).
Incubate the cells under standard cell culture conditions (37°C, 5% CO₂) for 2 hours.
2.4 Washing: Aspirate the probe solution, and wash the cells 3 times with PBS or fresh culture medium to remove unbound probes.
2.5 Imaging Detection:
Observe directly using a confocal microscope.
Excitation (λex): 647 nm
Emission (λem): Collect signals from the 663-738 nm channel (NIR signal after MB release, with a peak at ~684 nm).

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

MB-m-borate (2 mM, 100 μL; intratumoral injection; single dose) induces over 3-fold higher fluorescence intensity at subcutaneous melanoma xenograft sites in BALB/c-nu female nude mice compared to vehicle controls, enabling specific detection of melanoma^[1].

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

558.54

C₃₁H₃₉BN₄O₃S

CN(C1=CC=C2C(SC3=C(N2C(NCCC4=CC(B5OC(C)(C(C)(O5)C)C)=CC=C4)=O)C=CC(N(C)C)=C3)=C1)C

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Peng H, et al. Dual-Locked Near-Infrared Fluorescent Probes for Precise Detection of Melanoma via Hydrogen Peroxide-Tyrosinase Cascade Activation. Anal Chem. 2022;94(2):1070-1075.