Cyanine5.5 Maleimide is a near-infrared fluorescent probe and the maleimide derivative of Cyanine5.5. Its maleimide group covalently reacts with thiol (-SH) groups on proteins, antibodies, and other biomolecules to form stable thioether bonds. Emitting in the near-infrared window, this dye reduces biological autofluorescence and improves tissue imaging performance. Cyanine5.5 maleimide is widely used for in vivo small-animal imaging probe construction, protein labeling, and flow cytometry studies.

Cyanine5.5 maleimide chloride is a conjugated dye composed of the Cyanine5.5 fluorophore and a maleimide reactive group. Cyanine 5.5 is a near-infrared fluorescent cyanine dye widely used for in vivo small animal imaging. It can be employed to label proteins, antibodies, peptides, and nanoparticles. Maleimide is a commonly used group in bioconjugation reactions, capable of forming stable thioester linkages with sulfhydryl groups (-SH) through Michael addition, thereby achieving labeling. Although amino groups (such as the side chains of lysine and arginine) also exhibit reactivity, under neutral or slightly acidic buffer conditions, maleimide demonstrates significantly higher selectivity toward sulfhydryl groups (reacting over 1000 times faster than with amino groups), enabling rapid, highly selective, and high-yield labeling. Furthermore, sulfhydryl groups are widely present as functional groups in biomolecules, such as cysteine in proteins and disulfide bonds. Consequently, maleimide/thiol labeling has become the second most commonly used bioconjugation method after NHS/amine labeling.

DMSO: 40 mg/mL (53.95 mM), Sonication is recommended.

10% DMSO+40% PEG300+5% Tween-80+45% Saline: 1.5 mg/mL (2.02 mM), Sonication is recommended.