Azido-PEG5-PFP ester | CAS 1818294-48-2

Azido-PEG5-PFP ester is a PEG-based azide functional reagent that combines a terminal azide handle for copper-free or copper-mediated click chemistry with a reactive pentafluorophenyl (PFP) ester for rapid acylation of primary amines. The reagent’s flexible PEG5 spacer supports aqueous compatibility and reduces steric constraints, making it a practical linking and labeling intermediate for constructing azide-bearing biomolecules and materials. In research and industrial bioconjugation workflows, Azido-PEG5-PFP ester is commonly used to introduce an azide functionality onto proteins, peptides, or polymer backbones prior to downstream conjugation to alkynes or other click partners.

1. Protein Labeling Workflows

Azido-PEG5-PFP ester is widely used to install azide groups onto proteins and peptides through PFP-ester-mediated coupling to accessible primary amines, enabling subsequent click conjugation to alkyne-functional probes. Researchers often select this reagent when they need a defined, flexible spacer between the protein surface and the click handle, improving labeling uniformity and preserving binding or recognition properties in downstream assays. The PEG5 linker can also help mitigate aggregation and nonspecific interactions during probe preparation, which is particularly valuable for surface labeling and multi-step conjugation schemes.

2. Surface and Material Functionalization

Azido-PEG5-PFP ester supports azide introduction onto amine-containing surfaces and biomaterials, including polymeric scaffolds, hydrogel components, and functionalized beads used in analytical chemistry and chemical biology. By coupling the PFP ester to available amines, the reagent creates stable, click-ready azide sites that can be patterned or assembled with complementary alkyne-bearing ligands, reporters, or capture reagents. This approach is frequently adopted in materials research where spatially addressable or modular assembly of functional components is required, such as building layered coatings, immobilizing affinity tags, or preparing clickable polymer networks.

3. Fluorophore and Probe Conjugation

Azido-PEG5-PFP ester is commonly used as a bridge reagent to generate azide-functional imaging and detection probes from amine-containing fluorophores, affinity reagents, or reporter constructs. After azide installation, the resulting click handle enables efficient coupling to alkyne-tagged dyes, quencher systems, or imaging moieties, allowing rapid exchange of reporter components without redesigning the entire labeling strategy. The PEG5 spacer is particularly helpful when probe performance depends on minimizing steric hindrance near the conjugation site, supporting robust probe construction for microscopy, flow-based assays, and multiplexed reagent panels.

4. Polymer and Nanoparticle Building Blocks

Azido-PEG5-PFP ester is used to functionalize amine-terminated polymers and nanoparticle surfaces to create azide-bearing macromolecular building blocks for modular assembly. In polymer chemistry and biomaterials development, the reagent enables post-functionalization strategies where click partners can be incorporated at a later stage, supporting the fabrication of conjugated polymers, clickable coatings, and nanoparticle-ligand constructs. This workflow is attractive for researchers who need a versatile intermediate that can be carried through formulation and processing steps before final attachment of targeting ligands, imaging reporters, or analytical tags via click chemistry.