ATTO 700 maleimide

ATTO 700 maleimide is a thiol-reactive fluorescent labeling reagent built on an ATTO 700 fluorophore, enabling covalent attachment to biomolecules and materials that present accessible cysteine residues or engineered thiols. Its strong red/NIR spectral output is commonly leveraged for fluorescence microscopy, flow cytometry, and fluorescence-based assay development where robust signal in the longer-wavelength range is advantageous. The maleimide functional group supports fast, selective conjugation under standard bioconjugation workflows, making it a practical choice for preparing labeled proteins, peptides, affinity reagents, and thiol-functionalized surfaces.

1. Protein And Peptide Labeling

ATTO 700 maleimide is widely used to fluorescently tag proteins and peptides for downstream imaging and quantitative fluorescence assays. Researchers typically incorporate it into workflows that require site-selective labeling of cysteine-containing targets, including recombinant proteins with engineered single-cysteine sites and peptide ligands used for binding studies. The resulting ATTO 700 conjugates are commonly employed in fluorescence microscopy to visualize biomolecular localization, and in plate-based fluorescence assays to track binding, uptake, or interaction dynamics with labeled partners.

2. Flow Cytometry Cell Labeling

ATTO 700 maleimide supports fluorescence labeling strategies for flow cytometry where red-emitting dyes help reduce spectral interference from common background autofluorescence. In cell-surface or extracellular labeling workflows, investigators use thiol-reactive conjugation to attach ATTO 700 to thiol-bearing antibodies, affinity binders, or other targeting reagents, enabling quantitative measurement of labeled populations by FACS. This reagent is also used to prepare fluorescent standards and labeled controls for compensation and gating, particularly when longer-wavelength channels are preferred for multiplex panels.

3. Thiol-Functionalized Surface Engineering

ATTO 700 maleimide is frequently applied to functionalize biomaterial surfaces and experimental platforms that carry thiol groups, including hydrogels, polymer coatings, and nanoparticles modified with reactive thiols. Materials scientists and chemical biologists use the covalent attachment of ATTO 700 to create stable fluorescent interfaces for studying adsorption, cell-material interactions, and spatial distribution of biomolecules on engineered substrates. Labeled surfaces prepared with maleimide-thiol chemistry are also used in microscopy-based assays to monitor coating uniformity, diffusion/retention behavior, and biomolecular immobilization patterns.

4. Fluorescent Probe Construction

ATTO 700 maleimide is used as a labeling building block for constructing fluorescent probes and conjugate reagents that require a defined dye-to-biomolecule ratio. Probe developers commonly conjugate ATTO 700 to thiol-containing targeting ligands, enzyme substrates, or recognition elements to generate fluorescent readouts for binding and interaction studies. In these workflows, the covalent maleimide attachment helps ensure that the fluorescent signal remains associated with the probe construct during washing steps, enabling reproducible imaging and quantification in assay formats such as endpoint fluorescence measurements and microscopy-based tracking experiments.