ATTO 647 NHS ester

ATTO 647 NHS ester is a reactive ATTO 647 fluorophore formulated as an N-hydroxysuccinimide (NHS) ester, enabling efficient covalent labeling of primary amines on proteins, peptides, and other amine-containing biomolecules. Its far-red emission profile supports fluorescence microscopy and flow cytometry workflows where reduced background and strong spectral separation are advantageous. Researchers commonly use it to generate fluorescent conjugates for imaging, quantification, and assay development.

1. Protein And Antibody Labeling

ATTO 647 NHS ester is widely used to prepare fluorescently labeled proteins for immunoassays, binding studies, and imaging reagents, including antibody conjugates and affinity reagents. The NHS ester reacts with lysine side-chain amines and N-terminal amines, allowing straightforward post-labeling of purified targets used in fluorescence microscopy and plate-based fluorescence assays. In chemical biology and biomolecular interaction studies, the resulting far-red conjugates are frequently chosen to improve multiplexing flexibility and to support readouts with minimal spectral overlap when paired with green or orange fluorophores.

2. Fluorescence Microscopy Staining

ATTO 647 NHS ester supports cellular and subcellular visualization workflows by covalently tagging amine-rich biomolecules used as staining components, probes, or labeling partners in microscopy experiments. Researchers use ATTO 647-labeled proteins (for example, targeting ligands, secondary reagents, or structural binders) to track localization patterns with far-red fluorescence, which can be particularly useful for imaging in thicker samples or in multi-color experiments. The NHS-ester chemistry also enables labeling of fixed or permeabilized samples when compatible with the downstream staining and wash conditions required by the specific microscopy protocol.

3. Flow Cytometry Conjugate Preparation

ATTO 647 NHS ester is commonly employed in flow cytometry reagent development to generate far-red fluorescent conjugates for labeling cells and cell-associated targets. By attaching the dye to antibodies, proteins, or other amine-containing binders, researchers can produce staining reagents that integrate well into multi-parameter cytometry panels, where far-red detection helps separate signals from autofluorescence and other fluorophores. This labeling approach is frequently used for quantitative binding comparisons, phenotyping workflows, and assay development where consistent covalent labeling of the targeting component is required.

4. Fluorescent Bioassay Reagent Development

ATTO 647 NHS ester is used to create fluorescent assay reagents by labeling proteins and peptides that serve as reporters, standards, or binding components in fluorescence-based bioassays. In biochemical and molecular biology workflows, covalent dye labeling helps maintain reagent stability during incubation and washing steps, supporting reproducible signal generation in plate formats and imaging-compatible assays. The far-red fluorescence of ATTO 647 is also leveraged to reduce interference from common assay backgrounds when building multi-color or sequential readout assay designs.