Cyanine5.5 maleimide | CAS 1594414-90-0

Cyanine5.5 maleimide is a thiol-reactive cyanine dye designed for covalent fluorescent labeling via maleimide chemistry. The extended conjugation of the cyanine scaffold provides strong far-red fluorescence that is widely used for fluorescence imaging workflows, including conjugate preparation for microscopy and fluorescence-based assays. Because the dye is supplied as a maleimide, it is commonly paired with thiol-containing biomolecules to generate stable dye conjugates for tracking, localization, and detection.

1. Biomolecule Thiol Labeling

Cyanine5.5 maleimide is frequently used by chemical biology and protein engineering groups to label cysteine-containing peptides, antibodies (after controlled reduction), and other thiol-bearing biomolecules for fluorescence imaging and assay development. The maleimide handle enables direct conjugation to accessible sulfhydryl groups, allowing researchers to prepare fluorescent conjugates for studying binding interactions, trafficking, and biomolecular dynamics in labeled form. In practice, this reagent is often selected when far-red emission is preferred to reduce spectral overlap with common visible fluorophores.

2. Fluorescence Microscopy Tracing

Cyanine5.5 maleimide supports cellular and biomolecular fluorescence microscopy experiments where far-red signal provides improved separation from autofluorescence and multicolor panels. Researchers use dye-labeled proteins, peptides, or other thiol-reactive conjugates to visualize localization patterns, track binding to targets, or follow distribution of labeled components across experimental time. The covalent labeling approach helps maintain dye association during washing steps typical of fixed-sample imaging and multistep staining workflows.

3. Flow Cytometry Conjugate Staining

Cyanine5.5 maleimide is used in flow cytometry reagent development to generate far-red fluorescent conjugates for labeling cell-associated targets. Teams performing immunophenotyping workflows often prepare dye-labeled affinity reagents or thiol-modified binding constructs to enable quantitative fluorescence readouts in the far-red channel. By starting from maleimide-functionalized dye, conjugation can be tailored to thiol-bearing biomolecules used as staining reagents for panel-based cytometry experiments.

4. Nanoparticle And Polymer Labeling

Cyanine5.5 maleimide is also applied to label thiol-functionalized nanoparticles, polymer materials, and biomaterial surfaces for fluorescence tracking and material characterization. In these workflows, the dye conjugate serves as a stable reporter to monitor dispersion, surface association, and retention of labeled materials under experimental conditions. Materials researchers commonly incorporate the far-red cyanine signal into imaging and characterization pipelines to distinguish labeled constructs from background fluorescence in complex samples.