ATTO 647N NHS ester

ATTO 647N NHS ester is a reactive, dye-based labeling reagent built on the ATTO 647N fluorophore, designed for covalent attachment to primary amine groups. As an NHS ester, it is widely used to prepare fluorescent conjugates for fluorescence microscopy, flow cytometry, and fluorescence-based assays where bright far-red emission and low background are advantageous. The activated ester enables straightforward reagent-to-biomolecule workflows for producing labeled proteins, antibodies, peptides, and other amine-containing targets.

1. Protein And Antibody Labeling

ATTO 647N NHS ester is frequently used by protein engineers and antibody researchers to generate far-red fluorescent conjugates for imaging and assay development. The NHS ester reacts with lysine residues on proteins and antibodies to yield stable amide-linked labeling, supporting workflows such as labeling of secondary antibodies for immunofluorescence, fluorescent tagging of purified targets for binding studies, and preparation of fluorescent standards for assay qualification. Far-red ATTO 647N emission is commonly selected when multiplexing with visible channels or when minimizing spectral overlap with green/orange fluorophores is important.

2. Fluorescence Microscopy Staining

ATTO 647N NHS ester supports cellular and molecular fluorescence microscopy by enabling labeling of amine-bearing biomolecules used as stains, probes, or targeting reagents. Researchers use ATTO 647N-labeled proteins and affinity reagents to visualize binding patterns on fixed cells, to track biomolecule localization in microscopy experiments, and to construct multi-component staining panels where far-red detection improves separation from autofluorescence. The covalent labeling approach helps maintain signal stability during washing steps typical of microscopy workflows.

3. Flow Cytometry Conjugate Preparation

ATTO 647N NHS ester is used in flow cytometry reagent development to prepare far-red fluorescent conjugates for cell-surface or intracellular labeling strategies that rely on amine-reactive coupling. Common use cases include generating fluorescently labeled antibodies, protein probes, or labeling reagents that are then used to quantify binding by flow cytometry readouts. The far-red spectral region helps reduce interference from instrument background and supports multiplex panels when combined with fluorophores emitting at shorter wavelengths.

4. Fluorescent Bioassay Reagents

ATTO 647N NHS ester is also applied in fluorescence assay development to generate labeled components for binding assays, detection reagents, and tracer molecules. Assay developers label proteins or peptides with ATTO 647N to create fluorescent reporters that can be monitored in plate-based formats, enabling consistent readout of binding or interaction events using far-red fluorescence detection. Covalent NHS-ester labeling is particularly useful when labeled reagents must withstand washing, dilution, or incubation conditions typical of fluorescence-based screening and characterization experiments.