endo-BCN-PEG12-acid | CAS 2183440-27-7

endo-BCN-PEG12-acid is a strained cyclooctyne (BCN) click chemistry reagent bearing a PEG12 spacer and a terminal carboxylic acid, designed for copper-free, bioorthogonal labeling via strain-promoted azide–alkyne cycloaddition (SPAAC). The PEGylated, acid-functional handle supports aqueous compatibility and enables straightforward conjugation to amine-containing biomolecules, polymer backbones, or activated surfaces. This reagent is commonly used in chemical biology workflows where stable, catalyst-free conjugation is required for probe, material, and imaging construct assembly.

1. Biomolecule Conjugation

endo-BCN-PEG12-acid is used to install a BCN reactive handle onto proteins, peptides, and other macromolecular platforms through the terminal carboxylic acid, which can be coupled to amine-bearing targets using standard carbodiimide or activated ester chemistries. The PEG12 spacer helps maintain solubility and reduces steric constraints, making endo-BCN-PEG12-acid a practical choice for preparing azide-functional biomolecule conjugates that are later combined with azide-tagged partners in SPAAC labeling. Researchers rely on this reagent to generate well-defined, bioorthogonal labeling reagents for downstream assay development and molecular probe construction.

2. Surface and Material Functionalization

endo-BCN-PEG12-acid is well suited for functionalizing polymeric materials, hydrogel surfaces, and inorganic or oxide-bearing substrates where carboxylic acid activation enables immobilization or surface grafting. Incorporating the BCN motif onto a material allows subsequent SPAAC coupling to azide-modified reporters, biomolecules, or affinity ligands, enabling modular build-up of functional coatings and patterned interfaces. The PEG12 chain contributes to improved accessibility of the strained cyclooctyne at the material interface, which is particularly valuable when labeling bulky targets or when maintaining aqueous compatibility is important for imaging and diagnostic reagent development.

3. Molecular Imaging Probe Assembly

endo-BCN-PEG12-acid is frequently used as a BCN-bearing building block to prepare imaging probes and detection reagents that require copper-free conjugation to azide-functional reporter components. The PEG12 linker supports probe solubility and can help tune the effective distance between the reactive site and the imaging moiety, which is useful when assembling multicomponent constructs such as fluorescent or enrichment-tagged reagents. By providing a carboxylic acid handle for pre-conjugation, endo-BCN-PEG12-acid fits common probe manufacturing workflows where a BCN-functional intermediate is generated first and then clicked to an azide partner under mild, catalyst-free conditions.

4. Diagnostic Reagent Development

endo-BCN-PEG12-acid supports the preparation of diagnostic and analytical reagents that benefit from stable, orthogonal coupling chemistry between BCN and azide functionalities. The terminal acid enables incorporation into reagent formats such as labeled affinity reagents, capture probes, and polymer-supported assay components, while the PEG12 spacer helps maintain reactivity and reduces nonspecific steric effects in complex assay buffers. Teams developing assay reagents for research use often choose endo-BCN-PEG12-acid to create BCN-functional intermediates that can be rapidly and reproducibly assembled with azide-tagged detection elements via SPAAC, streamlining the construction of modular diagnostic workflows.