IRDye® 680RD NHS Ester

IRDye® 680RD NHS Ester is an NHS-ester activated near-infrared fluorophore designed for covalent fluorescent labeling of primary amines on proteins, peptides, and other biomolecules. Its emission in the far-red/near-infrared region supports low-background imaging workflows where autofluorescence is reduced, making it a common reagent for constructing fluorescent conjugates for optical detection. Researchers use this dye to prepare antibody and protein conjugates, labeling standards, and imaging reagents where stable amide-bond formation is required.

1. Antibody Conjugate Labeling

IRDye® 680RD NHS Ester is frequently used by immunochemistry and molecular imaging groups to generate near-infrared antibody conjugates for fluorescence-based binding studies and visualization. The NHS-ester reacts with lysine residues and N-terminal amines to form stable amide linkages, enabling consistent dye loading for downstream optical readouts. Typical workflows include labeling secondary antibodies, targeting ligands, or affinity reagents for use in fluorescence imaging of biomolecular interactions in microplate formats, imaging systems, and blotting-style assays.

2. Protein and Peptide Labeling

IRDye® 680RD NHS Ester supports fluorescent labeling of purified proteins and peptides for quantitative tracking in biochemical assays and molecular biology workflows. By targeting accessible primary amines, the reagent enables preparation of fluorescent protein conjugates used to monitor binding, uptake, or immobilization on assay surfaces. Researchers also employ labeled peptides as fluorescent tracers in protein interaction studies, where far-red emission helps reduce interference from common sample autofluorescence.

3. Western Blot And Gel Imaging

IRDye® 680RD NHS Ester is used to prepare fluorescent detection reagents for gel- and blot-based workflows that rely on near-infrared imaging. Labeled antibodies or protein standards generated from this NHS-ester are commonly used to visualize targets with optical detection systems that read far-red signals. In these applications, the dye's spectral region and covalent labeling chemistry help produce robust, reproducible fluorescence signals for documentation and comparative analysis across experimental conditions.

4. Fluorescent Tracer Standards

IRDye® 680RD NHS Ester is also applied in the preparation of fluorescent reference materials and tracer standards used to calibrate imaging and quantification workflows. Conjugates prepared from this dye are used as consistent fluorescence controls for instrument setup, method development, and normalization in optical assays. Laboratories that build multiplexed or multi-sample imaging pipelines often rely on standardized far-red fluorescent conjugates to support reproducible signal interpretation across runs.