Cyanine7.5 maleimide

Cyanine7.5 maleimide is a reactive cyanine dye designed for thiol-selective conjugation via its maleimide functional group, enabling fluorescent labeling of biomolecules and surfaces with emission in the far-red region. This dye format is frequently used in fluorescence imaging and labeling workflows where robust far-red signal is advantageous for multiplexing and background reduction strategies. In bioconjugation, the maleimide handle supports straightforward attachment to cysteine-containing targets, including proteins, peptides, and thiol-functionalized materials.

1. Protein And Peptide Labeling

Cyanine7.5 maleimide is widely used for far-red fluorescent labeling of proteins and peptides in chemical biology and biomolecular imaging workflows. Researchers typically employ it to generate fluorescent conjugates for binding studies, localization experiments, and mechanistic assays where cysteine residues or engineered cysteines provide attachment points. The maleimide reactivity supports efficient coupling to thiol-containing biomolecules, producing labeled conjugates that are compatible with fluorescence microscopy and fluorescence-based readouts. Far-red emission from the cyanine scaffold also helps reduce spectral overlap in multi-color experiments when paired with spectrally distinct fluorophores.

2. Thiol-Functional Surface Modification

Cyanine7.5 maleimide is used to fluorescently functionalize thiol-bearing surfaces and biomaterials, including hydrogel platforms, polymer coatings, and nanoparticle systems prepared with surface thiols. In materials science and biosensor development, the dye serves as a labeling reagent to visualize surface coverage, track material interactions, and confirm conjugation steps during platform assembly. By coupling to thiol groups on the material, the dye can be incorporated into engineered surfaces for subsequent imaging, washing-based characterization, and assay prototyping. This approach is particularly common when far-red fluorescence is preferred for imaging in complex backgrounds or when multiplexed surface labeling is required.

3. Fluorescent Probe And FRET Pair Construction

Cyanine7.5 maleimide is frequently incorporated into fluorescent probe development and FRET-based assay designs where a far-red cyanine acceptor or donor/acceptor component is needed. Bioconjugation teams use the maleimide handle to attach the dye to targeting ligands, recognition elements, or scaffold proteins that position the fluorophore at defined locations relative to a second fluorophore. The resulting labeled constructs are then applied in fluorescence resonance energy transfer measurements to monitor proximity-dependent signal changes in assay formats used for molecular interaction studies. This dye format is also used to build labeled standards and calibration reagents for instrument method development in far-red fluorescence channels.

4. Flow Cytometry Labeling Reagents

Cyanine7.5 maleimide supports preparation of far-red fluorescent labeling reagents for flow cytometry workflows that rely on thiol-reactive conjugation chemistry. In immunoassay development and cell-surface labeling experiments, researchers generate fluorescent conjugates by coupling the dye to thiol-containing antibodies, antibody fragments, or other cysteine-bearing binders. The far-red emission is commonly leveraged for multi-parameter cytometry panels, helping separate the cyanine signal from shorter-wavelength channels. Labeled conjugates prepared from Cyanine7.5 maleimide are used to quantify binding and to track labeled biomolecules on cells in fluorescence-based analysis pipelines.