IRDye® 750 Carboxylate

IRDye® 750 Carboxylate is a near-infrared (NIR) fluorescent dye designed for covalent conjugation via its carboxylate functionality. Its emission in the far-red/NIR region supports low-background imaging workflows where visible autofluorescence is a concern, making it widely used for fluorescence labeling of proteins, antibodies, and other biomolecules in optical imaging and fluorescence-based assays.

1. Antibody And Protein Labeling

IRDye® 750 Carboxylate is routinely used by antibody and protein engineering groups to generate fluorescently labeled immunoreagents for binding studies and fluorescence readouts. The dye's carboxylate handle enables chemical conjugation to biomolecules that have been functionalized with complementary amine or other reactive groups, producing conjugates that are compatible with standard fluorescence imaging systems and NIR-capable detection setups. This labeling format is commonly leveraged in research workflows where NIR signal helps reduce background from biological samples such as cell lysates, tissue sections, or complex assay matrices.

2. Fluorescence Imaging Of Biomolecules

IRDye® 750 Carboxylate is applied in optical imaging experiments to visualize the distribution of labeled biomolecular constructs in vitro and in ex vivo sample formats. Researchers use dye-conjugated targets to track localization, compare binding conditions, and quantify relative fluorescence intensity across experimental groups using NIR imaging instruments. The far-red/NIR spectral window is particularly valuable when background fluorescence from sample components would otherwise obscure signal in visible channels, supporting clearer imaging of labeled probes in microscopy and whole-sample fluorescence workflows.

3. NIR Fluorescence Assay Development

IRDye® 750 Carboxylate is frequently incorporated into fluorescence assay development for researchers building detection reagents that rely on stable, covalent fluorescent labeling. Conjugates prepared from this dye are used in assay formats where fluorescence intensity is read out on NIR-compatible plate readers, imaging systems, or custom optical detection platforms. Typical applications include labeling of assay reagents such as secondary binders, affinity reagents, or reporter constructs used to monitor binding events, wash steps, or endpoint signal in biochemical and cell-based assays.

4. Bioconjugate Standards And Controls

IRDye® 750 Carboxylate is also used to prepare fluorescent reference materials and assay controls for method development and instrument verification. Laboratories generate labeled standards to normalize imaging or fluorescence quantification across experiments, including comparisons between labeling batches and conjugate lots. In multiplex or multi-channel workflows, NIR labeling with this dye helps establish consistent reference signals in a spectral region that is often separated from common visible fluorophores, supporting robust experimental design during reagent optimization.