IRDye® 680LT NHS Ester

IRDye® 680LT NHS Ester is an N-hydroxysuccinimide ester-activated near-infrared fluorophore designed for covalent fluorescent labeling of primary amines on proteins and peptides. Its far-red emission supports low-background imaging workflows in fluorescence microscopy and in vivo-mimicking optical readouts, while the NHS ester enables straightforward conjugate preparation for research-grade molecular imaging reagents.

1. Protein Conjugation Labeling

IRDye® 680LT NHS Ester is widely used by protein engineering and chemical biology groups to generate fluorescently labeled antibodies, antibody fragments, enzymes, and affinity proteins for optical tracking and binding studies. The NHS ester reacts with lysine side-chain primary amines and N-termini, enabling preparation of labeled conjugates for downstream applications such as Western blot-style detection, fluorescence-based binding assays, and qualitative localization experiments. Researchers also use the resulting IRDye® 680LT conjugates as imaging tags in probe libraries where consistent far-red brightness and amine-reactive chemistry are required.

2. Fluorescence Imaging Probes

IRDye® 680LT NHS Ester supports the development of near-infrared fluorescence imaging reagents used in microscopy and optical imaging platforms that benefit from reduced tissue autofluorescence and improved signal penetration compared with visible dyes. Molecular imaging workflows often incorporate IRDye® 680LT-labeled targeting ligands, carrier proteins, or biomolecule tracers to visualize distribution in labeled samples, including fixed specimens and prepared imaging targets. In assay development settings, the dye-conjugates are also used as fluorescent reporters to monitor reagent binding, wash steps, and relative uptake in multi-step workflows.

3. Bioconjugation for Assay Development

IRDye® 680LT NHS Ester is commonly selected for building fluorescent standards and assay reagents where covalent attachment to amine-containing biomolecules is needed for reproducible signal reporting. In fluorescence-based bioassays, researchers prepare labeled components such as detection antibodies, secondary reagents, or protein-binding controls to enable optical readouts in plate formats or imaging-assisted quantification. The amine-reactive NHS functionality helps streamline conjugate generation for kit-like reagent development in research laboratories, where stable dye attachment to biomolecular scaffolds is important for consistent handling and storage.

4. Surface and Material Functionalization

IRDye® 680LT NHS Ester is used in biomaterials and surface chemistry workflows to fluorescently tag amine-functionalized polymers, nanoparticles, and biomaterial coatings for characterization and localization studies. By reacting with surface-exposed primary amines, the dye can be incorporated onto engineered materials to visualize coating uniformity, track material distribution, or quantify surface-associated signal in imaging experiments. This approach is frequently adopted in materials research labs that require a near-infrared imaging handle for monitoring functionalized surfaces without relying on noncovalent dye adsorption.