endo-BCN-PEG2-acid | CAS 1993134-72-7

endo-BCN-PEG2-acid is a strained cyclooctyne (BCN) click chemistry reagent equipped with a short PEG spacer and a terminal carboxylic acid handle for downstream conjugation. As a cyclooctyne-based bioorthogonal reagent, it is commonly used in strain-promoted azide–alkyne cycloaddition (SPAAC) workflows where rapid, catalyst-free labeling is required. The endo-BCN geometry and PEG2-acid functionality make it well suited for building azide-reactive probes, surface coatings, and imaging reagents that require a defined hydrophilic linker and an acid for coupling or material attachment.

1. Biomolecule Conjugation

endo-BCN-PEG2-acid is widely used to functionalize azide-bearing biomolecules such as peptides, nucleic-acid constructs, and protein labeling scaffolds in research settings that prioritize bioorthogonal compatibility. The terminal carboxylic acid enables straightforward attachment to amine-containing carriers, linkers, or activated surfaces prior to or after click labeling, supporting modular probe design. The PEG2 spacer improves aqueous handling and helps reduce nonspecific interactions during conjugate preparation, which is valuable for generating consistent labeling reagents for biochemical assays and molecular biology toolkits.

2. Cell Imaging Probes

endo-BCN-PEG2-acid serves as a key building block for preparing SPAAC-compatible fluorescent or luminescent imaging probes that are assembled through azide–BCN coupling. Researchers use the PEG2-acid functionality to incorporate the BCN moiety into probe architectures that include solubilizing linkers and reactive handles for further derivatization, such as attachment to dyes, nanoparticles, or imaging modalities. This reagent is particularly relevant when probe assembly must be performed under mild, catalyst-free conditions to preserve sensitive labeling components and maintain reproducible probe behavior across experiments.

3. Biomaterials Surface Functionalization

endo-BCN-PEG2-acid is used to introduce cyclooctyne functionality onto polymeric and hydrogel materials that are subsequently reacted with azide groups for surface patterning and material functionalization. The carboxylic acid handle supports coupling strategies to immobilize BCN-bearing linkers onto material backbones or to tether BCN units to reactive coatings, enabling spatially controlled installation of bioorthogonal ligands. In biomaterials workflows, the PEG2 spacer is commonly leveraged to improve wettability and reduce steric hindrance at the interface, supporting reliable downstream azide-based conjugation for engineered surfaces and assay-ready materials.

4. Diagnostic Reagent Building Blocks

endo-BCN-PEG2-acid is frequently incorporated into diagnostic-reagent development pipelines where azide-functional capture elements are assembled with BCN-bearing reporters or affinity components via SPAAC. The reagent’s acid functionality supports integration into multicomponent reagent designs, including linker-mediated attachment to solid supports, beads, or scaffold systems used for assay construction. By enabling efficient azide-reactive coupling without the need for copper catalysts, endo-BCN-PEG2-acid helps maintain compatibility with sensitive labeling components and supports consistent reagent assembly for high-throughput laboratory workflows.