Azido-PEG4-amido-Lys(Fm°C)-acid

Azido-PEG4-amido-Lys(Fm°C)-acid is a PEGylated, azide-bearing amino acid derivative designed for copper-free and/or copper-mediated click chemistry workflows, enabling site-specific installation of functional payloads onto biomolecules and biomaterial surfaces. The reagent combines an azide handle with a lysine-based scaffold and an Fm°C-protected motif, which supports controlled conjugation strategies in chemical biology and materials research. Its PEG4 spacer improves aqueous compatibility and reduces steric constraints, making it a practical building block for constructing labeled probes, functionalized polymers, and modular bioconjugates.

1. Biomolecule Site Labeling

Azido-PEG4-amido-Lys(Fm°C)-acid is commonly used as a modular azide building block for introducing click-ready functionality into peptides, proteins, and peptide-mimetic constructs during probe development and assay optimization. Researchers incorporate the lysine-based handle to achieve defined attachment points, while the PEG4 spacer helps maintain solubility and accessibility of the azide for subsequent conjugation steps. This format is particularly useful when downstream workflows require attaching dyes, affinity tags, or imaging moieties through azide–alkyne coupling, including workflows that benefit from reduced steric hindrance and improved conjugation uniformity.

2. Surface and Hydrogel Functionalization

Azido-PEG4-amido-Lys(Fm°C)-acid supports the preparation of functional material surfaces and soft matrices by providing an azide group that can be clicked onto alkyne-bearing coatings, linkers, or crosslinking components. Materials scientists use this reagent to introduce bioorthogonal attachment sites on polymer films, nanoparticles, and hydrogel networks, where PEG spacing can improve diffusion of reactive partners and reduce nonspecific interactions. The lysine-derived scaffold also offers a convenient chemical motif for integrating the azide functionality into larger material architectures, enabling modular fabrication of cell-interaction platforms and reagent surfaces used in biochemical screening.

3. Targeted Molecular Imaging Probes

Azido-PEG4-amido-Lys(Fm°C)-acid is widely adopted in molecular imaging probe development as an azide precursor that can be coupled to imaging reporters bearing complementary alkyne handles. Chemical biology groups use the PEG4 spacer to preserve reporter accessibility after conjugation, which is important for maintaining consistent labeling density and minimizing aggregation in aqueous imaging reagent formulations. By separating the azide installation step from the final reporter attachment, teams can streamline probe synthesis and rapidly exchange imaging payloads, supporting iterative optimization of probe design for fluorescence, luminescence, and other label-based detection modalities.

4. Diagnostic Reagent Conjugates

Azido-PEG4-amido-Lys(Fm°C)-acid is used to build click-assembled diagnostic reagent conjugates where controlled installation of an azide functional group enables reliable coupling to detection chemistries. Diagnostic development teams and academic core facilities often rely on this reagent to generate modular intermediates that can be conjugated to affinity ligands, capture reagents, or reporter-bearing partners via azide–alkyne chemistry. The PEG4 linker contributes to water compatibility and helps maintain the reactivity of the azide during conjugation planning, supporting reproducible preparation of labeled reagents used in analytical assays and workflow validation.