N-(NHS-PEG3)-N-bis(PEG3-azide) | CAS 2182602-16-8

N-(NHS-PEG3)-N-bis(PEG3-azide) is a heterobifunctional PEG-based click chemistry reagent combining an N-hydroxysuccinimide (NHS) ester for amine-reactive conjugation with two terminal azide groups for subsequent copper-free or copper-mediated azide–alkyne cycloaddition. Its flexible PEG3 spacers and multivalent azide presentation make it well suited for building modular, distance-controlled bioconjugates and labeling reagents. The reagent is commonly used in chemical biology workflows where controlled attachment to proteins, peptides, or other primary-amine surfaces is followed by orthogonal “click” functionalization with alkyne-bearing probes.

1. Protein Labeling Workflows

N-(NHS-PEG3)-N-bis(PEG3-azide) is widely used to introduce azide handles onto proteins and peptide carriers via NHS ester chemistry, enabling downstream attachment of fluorescent dyes, affinity tags, or imaging moieties through azide–alkyne click reactions. The PEG3 spacers help reduce steric congestion around the azide termini, which is particularly useful when labeling bulky biomolecules or when multiple functionalizations are required from a single conjugation step. Researchers often choose this reagent when they need a robust and reproducible way to convert amine-bearing biomaterials into click-ready intermediates for probe assembly.

2. Multivalent Probe Assembly

N-(NHS-PEG3)-N-bis(PEG3-azide) supports multivalent construction of detection and research probes by providing two azide groups per conjugation event, allowing more than one alkyne-bearing component to be incorporated into a single final product. This design is valuable in molecular imaging reagent development and in assay reagent optimization, where probe brightness, binding avidity, or signal amplification can depend on how many functional groups are presented on the scaffold. The PEG-based linker also contributes to improved solubility and reduced non-specific interactions in many labeling contexts, supporting cleaner probe handling during screening and characterization.

3. Surface and Material Functionalization

N-(NHS-PEG3)-N-bis(PEG3-azide) is used to functionalize amine-containing surfaces and biomaterials, such as PEGylated polymer coatings, hydrogel matrices, and other NHS-compatible substrates, to install azide groups for subsequent click coupling. This approach is common in biomaterials science when researchers need spatially defined attachment of alkyne-bearing ligands, reporters, or crosslinking partners without relying on additional reactive groups on the material. By leveraging NHS reactivity for initial surface modification and azide click chemistry for later assembly, teams can modularly tune material composition and ligand density for downstream applications like platform reagent building and surface-based assay development.

4. Diagnostic Reagent Building Blocks

N-(NHS-PEG3)-N-bis(PEG3-azide) serves as a practical intermediate for constructing diagnostic and analytical reagent components that require controlled conjugation chemistry and modular assembly. In many laboratory and industrial workflows, the NHS ester step provides a straightforward way to attach azide functionality to carrier molecules used in detection formats, while the dual azide functionality supports incorporation of multiple reporter or capture elements via click coupling. This reagent is frequently selected when developers want flexible design space for building reagent conjugates that can be rapidly reconfigured by swapping alkyne-functional partners during method development and characterization.