Fluorescein-PEG3-amine | CAS 1807539-04-3

Fluorescein-PEG3-amine is a fluorescein-based fluorescent dye equipped with a short PEG3 linker terminating in a primary amine, enabling straightforward conjugation and stable incorporation into biomolecule and material workflows. The fluorescein chromophore provides strong visible fluorescence for labeling and imaging applications, while the PEG spacer helps improve handling and reduces steric constraints during downstream coupling. This reagent is commonly used to introduce a fluorescein tag onto proteins, peptides, and other amine-bearing targets for fluorescence readouts in microscopy and assay development.

1. Protein Fluorescent Labeling

Fluorescein-PEG3-amine is frequently used by bioconjugation researchers to install a fluorescein reporter onto proteins and peptides via amine-reactive coupling strategies, supporting fluorescence microscopy and fluorescence-based bioassays. The PEG3 spacer helps maintain labeling flexibility so the dye can remain optically accessible after conjugation, which is useful when preparing labeled antibodies, enzyme conjugates, or protein standards for assay calibration and imaging controls. Laboratories developing fluorescence-tagged biomolecules often choose this reagent when they want a primary amine handle for controlled attachment to their target or for building labeled conjugates that incorporate an amine-bearing linker.

2. Fluorescence Imaging Tracers

Fluorescein-PEG3-amine is used to create fluorescent tracers for cellular and materials imaging workflows where a visible green-emitting dye is required. Researchers incorporate fluorescein tags into labeled polymers, surface coatings, or biomaterial-associated probes to visualize distribution, transport, or localization using standard fluorescence microscopes and imaging systems. The PEG3-amine functionality supports conjugate construction for attaching the dye to amine-functionalized surfaces or carrier molecules, enabling consistent tracer preparation for comparative imaging experiments and protocol optimization.

3. Flow Cytometry Staining Reagents

Fluorescein-PEG3-amine is commonly leveraged in flow cytometry dye conjugate development when a fluorescein reporter is needed for labeling biomolecules used in cell staining panels. Conjugation to antibodies, affinity reagents, or other amine-containing binders enables fluorescence readout of target binding in suspension-based assays, supporting workflow development for immunostaining, binding assays, and reagent screening. The PEG3 linker and primary amine functionality help support reproducible conjugate preparation, which is particularly valuable when generating multicolor-compatible fluorescein-labeled reagents for instrument-based quantification.

4. Surface And Polymer Functionalization

Fluorescein-PEG3-amine is used to functionalize polymer materials and surfaces with a fluorescent moiety for characterization and visualization of functionalized substrates. Materials scientists and biomaterials teams incorporate the dye into amine-reactive coupling schemes to generate fluorescently tagged coatings, hydrogel components, or polymer conjugates used to monitor coating uniformity, surface retention, and spatial distribution. The PEG3 spacer can improve the accessibility of the fluorescein group on the material surface, supporting more reliable fluorescence signals during imaging-based quality checks and fluorescence tracking experiments.