Endo BCN-PEG18 NHS Ester

Endo BCN-PEG18 NHS Ester is a BCN (bicyclononyne) functionalized PEG18 NHS ester designed for copper-free strain-promoted click chemistry and efficient bioconjugation to primary amines. The reagent combines a cyclooctyne-like BCN handle with an NHS ester for stable amide formation, enabling attachment to proteins, peptides, and polymeric scaffolds under standard labeling conditions. Its PEG spacer improves aqueous compatibility and reduces steric constraints, making it a widely used building block for preparing BCN-functional biomaterials and imaging or assay platforms that rely on rapid SPAAC coupling.

1. Protein Labeling And Conjugation

Endo BCN-PEG18 NHS Ester is commonly used to introduce BCN click handles onto antibodies, enzymes, and other amine-containing proteins for subsequent copper-free conjugation. The NHS ester chemistry supports straightforward, site-agnostic amide coupling to lysine residues or N-termini, while the PEG18 spacer helps maintain accessibility of the BCN group for downstream reactions with azide-bearing partners. This workflow is frequently adopted in chemical biology and proteomics tool development where modular assembly of probes, affinity reagents, or multivalent constructs is required.

2. Molecular Imaging Probe Assembly

Endo BCN-PEG18 NHS Ester serves as a key intermediate for building imaging reagents that incorporate SPAAC-compatible BCN moieties on targeting ligands or carrier proteins. Researchers use the NHS ester to append the BCN handle to biomolecular vectors, then perform rapid copper-free ligation to azide-functional dyes, reporter tags, or imaging scaffolds to generate fluorescent or luminescent conjugates. The PEG18 linker is particularly valuable when constructing conjugates that must remain soluble and maintain effective labeling density without excessive steric shielding.

3. Biomaterial Surface Functionalization

Endo BCN-PEG18 NHS Ester is widely applied to functionalize hydrogel matrices, polymer coatings, and bead-based surfaces that present accessible amine groups. By coupling the NHS ester to surface-exposed primary amines, the reagent installs BCN handles that can later be clicked with azide-modified crosslinkers, capture ligands, or reporter molecules under copper-free conditions. The long PEG18 spacer supports improved diffusion and reduced nonspecific interactions, which is advantageous for creating reusable materials for research assays, affinity capture workflows, and surface-anchored labeling strategies.

4. Multivalent Assay And Sensor Platforms

Endo BCN-PEG18 NHS Ester is used to prepare BCN-functional components for multivalent assay reagents, including modular sensor architectures and reagent libraries. The NHS ester enables convenient incorporation of BCN groups into amine-bearing assay components such as scaffold proteins, peptide carriers, or polymeric linkers, allowing subsequent SPAAC assembly with azide-tagged reporters or recognition elements. This approach supports flexible design of high-avidity constructs and tunable labeling schemes for analytical and screening workflows that benefit from copper-free click compatibility.