endo-BCN-PEG12-NHS ester | CAS 2183440-26-6

endo-BCN-PEG12-NHS ester is an NHS-activated polyethylene glycol (PEG) conjugation reagent bearing an endo-bicyclononyne (endo-BCN) click handle. As a BCN-based strain-promoted click chemistry reagent, it is commonly used to install a bioorthogonal cyclooctyne functionality onto amine-bearing targets via NHS ester reactivity. The PEG12 spacer improves solubility and reduces steric constraints, supporting efficient downstream conjugation workflows for imaging, labeling, and material functionalization in chemical biology and biomaterials research.

1. Protein Surface Bioconjugation

endo-BCN-PEG12-NHS ester is widely used to functionalize proteins, peptides, and antibody fragments that contain accessible primary amines, enabling preparation of BCN-tagged biomolecules for subsequent strain-promoted azide–alkyne cycloaddition (SPAAC) with azide-functional partners. In practice, the PEG12 linker helps maintain colloidal stability and can improve labeling uniformity when attaching bulky click handles to lysine-rich surfaces. Researchers often incorporate this reagent into workflows for creating multivalent labeling reagents, affinity reagents, and modular probe platforms where the BCN functionality serves as the click-reactive moiety for later assembly.

2. Antibody and Affinity Probe Labeling

endo-BCN-PEG12-NHS ester supports click-ready modification of antibodies and affinity ligands for downstream conjugation to imaging dyes, reporter tags, or other biomolecular components bearing azide groups. The NHS ester chemistry enables straightforward coupling to amine groups on antibody scaffolds, while the endo-BCN moiety provides a robust bioorthogonal handle compatible with SPAAC-based assembly strategies. This approach is frequently adopted in molecular imaging probe development and assay reagent construction, where controlled installation of click functionality is needed to build conjugates with defined stoichiometry and flexible modularity.

3. Targeted Imaging Probe Assembly

endo-BCN-PEG12-NHS ester is used as a click handle precursor to generate BCN-functional imaging probes that can be assembled with azide-bearing fluorophores, nanoparticles, or imaging reporters through SPAAC. The PEG12 spacer is particularly valuable in imaging reagent design because it can reduce nonspecific interactions and improve the accessibility of the click handle on large or sterically demanding constructs. In molecular imaging and diagnostic reagent development, the reagent is commonly selected to produce well-defined intermediate conjugates that can be rapidly combined with multiple azide-labeled components, supporting scalable probe synthesis for research-grade imaging workflows.

4. Biomaterials and Surface Functionalization

endo-BCN-PEG12-NHS ester is also applied to functionalize biomaterial surfaces and bulk materials that present reactive amines, including PEGylated polymer coatings, hydrogel networks, and amine-derivatized substrates. By introducing endo-BCN groups using NHS ester coupling, materials can be subsequently patterned or decorated with azide-functional biomolecules, affinity ligands, or reporter elements via strain-promoted click chemistry. This strategy is used to create modular, bioorthogonal material interfaces for chemical biology studies, enabling controlled immobilization of functional components without requiring metal catalysts, which is advantageous for sensitive biomolecular assemblies and for maintaining compatibility with aqueous processing conditions.