Fluorescein-thiourea-PEG4-azide | CAS 1454662-54-4

Fluorescein-thiourea-PEG4-azide is a fluorescein-based azide-functional conjugate designed for fluorescence labeling workflows where a bioorthogonal azide handle is required. The PEG4 spacer helps reduce steric constraints around the fluorophore, supporting consistent labeling performance in conjugation and surface-modification formats. This reagent is commonly used to construct fluorescent bioconjugates and probe platforms via azide-compatible click chemistry, enabling downstream imaging and quantitative fluorescence readouts.

1. Biomolecule Click Labeling

Fluorescein-thiourea-PEG4-azide is used by chemical biology and glycobiology groups to install a fluorescein reporter onto biomolecules using azide-reactive click chemistry strategies. Researchers incorporate the azide handle into proteins, peptides, or other biomolecular constructs during probe assembly, then use the fluorescein signal for microscopy, plate-based fluorescence assays, or gel-based visualization. The PEG4 linker is particularly helpful when labeling bulky targets, where maintaining fluorophore accessibility can improve labeling uniformity across conjugate preparations.

2. Fluorescent Probe Construction

Fluorescein-thiourea-PEG4-azide serves as a building block for fluorescent probe development in assays that require modular attachment of a targeting or recognition element. In molecular imaging reagent workflows, teams use the azide functionality to couple fluorescein to affinity motifs, scaffold molecules, or engineered ligands, generating traceable constructs for localization studies and binding experiments. The fluorescein reporter supports common excitation/emission detection workflows, making the reagent useful for iterative probe optimization in research settings.

3. Surface And Polymer Functionalization

Fluorescein-thiourea-PEG4-azide is applied in biomaterials research to introduce a fluorescent tag onto surfaces and polymeric scaffolds through azide-compatible conjugation chemistries. Materials scientists use the resulting fluorescently labeled surfaces to track coating uniformity, monitor surface modification steps, and visualize interactions between materials and biological components under fluorescence microscopy. The PEG4 spacer can help present the fluorophore away from the surface, supporting clearer imaging of immobilized constructs and reducing steric masking during surface coupling.

4. Fluorescence Imaging Tracing

Fluorescein-thiourea-PEG4-azide is frequently used as a fluorescent tracer in cell and biomolecular imaging experiments where azide-based coupling is part of the labeling pipeline. Researchers prepare fluorescent conjugates that are then used to follow distribution, uptake, or association with labeled biomolecular assemblies in microscopy studies. Because the reagent provides both a fluorescein signal and a reactive azide handle for conjugate assembly, it fits workflows that require pre-labeling modularity before imaging readout.