ATTO 488 carboxylic acid | CAS 1443553-08-9

ATTO 488 carboxylic acid is a fluorescein-like ATTO 488 dye supplied as a carboxylic acid, enabling straightforward conversion into amine-reactive or activated ester labeling reagents for fluorescent conjugate preparation. Its bright green fluorescence in the visible range makes it a widely used tag for fluorescence imaging workflows where robust signal reporting is required. The dye's carboxyl functionality supports bioconjugation strategies to attach ATTO 488 to proteins, peptides, and other biomolecules for microscopy and fluorescence-based assays.

1. Protein And Antibody Labeling

ATTO 488 carboxylic acid is frequently used to generate fluorescently labeled proteins and antibodies for immunofluorescence, binding studies, and fluorescence microscopy workflows. Researchers typically convert the carboxylic acid into an activated form for conjugation to lysine-containing biomolecules, producing stable fluorescent conjugates that can be tracked in cell imaging experiments or in vitro binding assays. This dye format is also commonly selected when a green emission readout is preferred for multicolor panels, where ATTO 488 provides a convenient excitation/emission channel for imaging instrumentation.

2. Fluorescence Microscopy Staining

ATTO 488 carboxylic acid supports cellular and subcellular staining workflows through fluorescent conjugate construction, including labeling of targeting ligands, affinity reagents, and biomolecule probes used in microscopy. In practice, the dye is used to visualize localization patterns of labeled biomolecules in fixed-cell imaging and related microscopy experiments, where the carboxyl-derived conjugation chemistry enables attachment to a broad range of amine-bearing reagents. Fluorescent conjugates prepared from ATTO 488 are also used in colocalization studies, leveraging the dye's green fluorescence to map spatial relationships alongside other spectrally distinct labels.

3. Flow Cytometry Fluorescent Tags

ATTO 488 carboxylic acid is applied in flow cytometry by preparing ATTO 488-labeled antibodies, proteins, or other affinity reagents that report binding events through fluorescence emission. In typical workflows, labeled conjugates are incubated with cell suspensions, and fluorescence intensity is measured to quantify binding or uptake of the ATTO 488-tagged reagent. The carboxylic acid starting form is valued in reagent development because it can be routed into conjugation formats that yield consistent fluorescent labeling of biomolecules used for cytometry-based assays and sorting experiments.

4. Fluorescence Bioassay Reagent Development

ATTO 488 carboxylic acid is used to build fluorescent assay reagents by attaching the dye to biomolecular components involved in fluorescence readouts, such as detection antibodies, reporter proteins, or labeled ligands used in binding and wash-based assays. Researchers incorporate ATTO 488-labeled conjugates into plate-based fluorescence assays and imaging-compatible bioassays where a green fluorescent reporter is needed. This dye is also used in assay development when a visible-wavelength fluorophore is advantageous for standard fluorescence plate readers and imaging systems, enabling convenient monitoring of labeled reagent performance across experimental conditions.