endo-BCN-PEG8-acid | CAS 2126805-02-3

endo-BCN-PEG8-acid is a strained-alkyne click chemistry reagent built on the bicyclononyne (BCN) scaffold, designed for fast and selective conjugation via strain-promoted azide–alkyne cycloaddition (SPAAC). The molecule incorporates an eight-unit PEG spacer and a terminal carboxylic acid, which supports aqueous handling and enables downstream coupling to amine-bearing biomolecules, surfaces, or polymeric platforms. This reagent format is widely used in chemical biology and biomaterials workflows where a stable, bioorthogonal handle is needed to install functional cargo onto azide-functional targets without copper catalysis.

1. Bioorthogonal Surface Functionalization

endo-BCN-PEG8-acid is commonly used to functionalize azide-present surfaces and coatings in biosensor and materials research, where the PEG spacer helps reduce nonspecific interactions while maintaining conjugation efficiency. The terminal carboxylic acid enables straightforward immobilization strategies onto amine-terminated substrates or polymer backbones, allowing the BCN moiety to serve as a SPAAC-reactive group for subsequent attachment of azide-tagged ligands, probes, or nanoparticles. Researchers often select this reagent when they need a robust, water-compatible click handle for building patterned or modular surface chemistries for microscopy, analytical platforms, and assay development.

2. Targeted Probe and Imaging Conjugates

endo-BCN-PEG8-acid is frequently incorporated into probe design for molecular imaging and diagnostic reagent development, particularly when azide-bearing targeting vectors or reporter constructs must be conjugated under mild, copper-free conditions. The BCN group provides the click-reactive functionality, while the PEG8 chain helps tune solubility and spacing between the conjugation site and the probe payload, which can improve handling and reduce aggregation during labeling workflows. In practice, this reagent format supports the modular assembly of BCN-functional intermediate materials that can be clicked with azide-labeled fluorophores, affinity tags, or imaging reporters to generate homogeneous probe conjugates for research use.

3. Biomolecule Labeling and Tagging

endo-BCN-PEG8-acid is used as a bioorthogonal labeling reagent to attach functional groups to azide-modified biomolecules such as proteins, peptides, and nucleic-acid-associated constructs. The carboxylic acid functionality supports coupling to amine-bearing biomolecular scaffolds or to activated linkers, creating BCN-presenting conjugates that can later react with azide tags through SPAAC. Chemical biology teams value this approach for workflows that require rapid conjugation in aqueous buffers while avoiding copper, enabling cleaner labeling of sensitive biomolecular assemblies and facilitating downstream purification and characterization of tagged constructs.

4. PEG-Linker Building Blocks

endo-BCN-PEG8-acid is widely used as a PEG-based linker building block for constructing modular conjugation reagents and intermediate materials in biomaterials science. The PEG8 spacer provides a practical distance element between the BCN click site and the attachment point, which is beneficial in polymer conjugation, hydrogel functionalization, and nanoparticle surface engineering where steric accessibility and colloidal stability matter. By leveraging the terminal carboxylic acid for standard coupling chemistries, developers can generate BCN-functional materials that subsequently undergo SPAAC with azide-bearing components, supporting repeatable assembly of multi-functional constructs used across assay development, materials characterization, and research tool generation.