ATTO 655 NHS Ester | CAS 1341215-10-8

ATTO 655 NHS Ester is a reactive ATTO 655 fluorophore designed for covalent fluorescent labeling of primary amine-containing biomolecules and materials. As an N-hydroxysuccinimide (NHS) ester, it readily forms stable amide bonds under standard bioconjugation conditions, enabling bright far-red fluorescence readouts for imaging and assay development. Its spectral position supports multiplex-friendly workflows where separation from green/orange channels is advantageous.

1. Protein And Antibody Labeling

ATTO 655 NHS Ester is routinely used by protein chemistry and immunoassay teams to generate fluorescently labeled antibodies, antibody fragments, enzymes, and affinity reagents for fluorescence microscopy and fluorescence-based binding assays. The NHS ester chemistry targets lysine residues and N-termini, producing covalent conjugates that are well matched to workflows requiring stable dye attachment during washing steps, buffer exchanges, and multi-step assay protocols. Researchers often incorporate ATTO 655-labeled affinity reagents into secondary-antibody staining schemes, binding studies, and fluorescence readouts where far-red emission helps reduce background from autofluorescence.

2. Fluorescence Microscopy Staining

ATTO 655 NHS Ester supports cellular and biomaterial fluorescence microscopy by enabling robust labeling of amine-rich targets such as fixed-cell proteins, extracellular matrix components, and surface-associated biomolecules on engineered substrates. Imaging labs use ATTO 655 conjugates to visualize distribution patterns of labeled proteins in fixed samples, to track biomolecule localization on functionalized surfaces, and to build multi-color staining panels that benefit from far-red spectral separation. The covalent attachment provided by the NHS ester helps maintain labeling through typical staining and washing procedures used in microscopy sample preparation.

3. Flow Cytometry Conjugate Preparation

ATTO 655 NHS Ester is used by flow cytometry users to prepare far-red fluorescent conjugates for labeling cell-surface proteins, extracellular markers, and amine-containing reagents used in gating and population analysis. After conjugation to lysine-rich binding molecules such as antibodies or other affinity proteins, ATTO 655-tagged reagents enable fluorescence detection in channels that are commonly reserved for red/far-red emission to improve separation from autofluorescence and other fluorophores in multiplex panels. This reagent format is particularly useful in assay development settings where reproducible covalent labeling is preferred before titration and instrument optimization.

4. Biomaterial Surface Functionalization

ATTO 655 NHS Ester is applied in biomaterials and surface engineering workflows to fluorescently tag amine-functionalized polymers, beads, hydrogels, and coating layers for visualization of surface coverage and biomolecule immobilization. Materials scientists use the NHS ester to covalently attach ATTO 655 to surfaces or bulk materials bearing primary amines, enabling quantitative and qualitative fluorescence readouts during material characterization, coating optimization, and imaging-based verification. These labeled biomaterials are commonly used to monitor spatial organization and to support downstream experiments where labeled components must remain attached during handling and imaging.