IRDye® 800CW Maleimide | CAS 1279564-25-8

IRDye® 800CW Maleimide is a near-infrared fluorescent labeling reagent built on the IRDye® 800CW fluorophore and functionalized with a maleimide group for efficient thiol-reactive conjugation. The dye's long-wavelength emission supports low-background imaging workflows in protein labeling, imaging probe construction, and quantitative fluorescence readouts using common near-infrared detection systems.

1. Protein Thiol Labeling

IRDye® 800CW Maleimide is used by bioconjugation-focused labs to fluorescently tag proteins, antibodies, and antibody fragments through reaction with accessible cysteine thiols. Researchers commonly prepare fluorescently labeled affinity reagents for binding studies, workflow development in molecular imaging, and fluorescence-based characterization of conjugates. The maleimide handle enables straightforward incorporation of the near-infrared dye into thiol-containing biomolecules such as reduced antibodies, engineered cysteine variants, and other cysteine-rich targets, supporting downstream imaging and quantitative fluorescence measurements.

2. Western Blot And Gel Imaging

IRDye® 800CW Maleimide is routinely applied in fluorescence Western blotting and gel-based protein analysis where near-infrared detection improves visualization of labeled bands against background. Protein samples are labeled with the thiol-reactive dye (or used to label secondary reagents that carry reactive thiols), then imaged on compatible fluorescence imaging systems for documentation and densitometry. This workflow is particularly common in protein expression and purification verification, conjugate QC, and assay development where reproducible band intensity measurements are needed.

3. In Vivo Imaging Reagent Development

IRDye® 800CW Maleimide is frequently used during molecular imaging reagent development to generate near-infrared fluorescent conjugates for preclinical-style imaging studies in research settings. Teams in chemical biology and imaging technology use the dye to construct labeled probes from thiol-bearing biomolecules, including targeting ligands and carrier proteins, aiming for strong tissue-penetrating fluorescence readouts with reduced autofluorescence compared with visible dyes. The maleimide functionality supports modular probe construction, allowing researchers to tune labeling density and generate imaging reagents for instrument-specific near-infrared fluorescence acquisition.

4. Surface And Biomaterial Conjugation

IRDye® 800CW Maleimide is also applied to fluorescently functionalize surfaces and biomaterials that present reactive thiols, enabling fabrication of labeled coatings, assay platforms, and imaging-compatible materials. Researchers use the maleimide chemistry to attach the near-infrared fluorophore to thiol-functionalized polymers, hydrogels, or surface-modified substrates, creating stable fluorescent markers for material characterization and process monitoring. This approach supports microscopy and imaging readouts of material distribution, coating uniformity, and conjugate formation in biomaterials research and chemical biology workflows.