Biotin-PEG2-alkyne | CAS 2227450-68-0

Biotin-PEG2-alkyne is a biotinylated, PEG-linked terminal alkyne designed for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry. The reagent couples the high-affinity biotin handle to a flexible PEG spacer, enabling efficient conjugation to azide-bearing biomolecules, surfaces, and materials while maintaining accessibility of the biotin moiety. Its terminal alkyne functionality makes it widely used as a modular building block in affinity labeling workflows, probe construction, and surface functionalization where downstream streptavidin/avidin binding is central.

1. Streptavidin Affinity Labeling

Biotin-PEG2-alkyne is commonly used to generate biotin-tagged research reagents and labeling constructs by clicking onto azide-functional targets such as peptides, proteins, antibodies, or glycans. The PEG2 spacer helps preserve steric accessibility of the biotin group, which is important when the conjugate is used in pull-down assays, detection workflows, or qualitative mapping of biomolecular interactions. Researchers frequently incorporate this reagent to introduce a robust affinity handle that can be captured with streptavidin or avidin reagents for downstream analysis, enrichment, or normalization across experimental samples.

2. Biomolecular Conjugation Probes

Biotin-PEG2-alkyne serves as a versatile probe intermediate for building azide-containing imaging and analytical tools, including biotinylated affinity probes for microscopy, flow-based assays, and biochemical characterization. By installing the biotin handle via click chemistry, the reagent supports modular assembly of multi-component systems where the biotin moiety acts as a universal attachment point for streptavidin-based reporters, nanoparticles, or secondary detection reagents. This approach is especially valuable when researchers need consistent conjugation chemistry across different biomolecular scaffolds while maintaining a flexible linker environment around the affinity tag.

3. Surface and Material Functionalization

Biotin-PEG2-alkyne is used to functionalize azide-present surfaces and materials, enabling the creation of biotin-enabled interfaces for biosensing, affinity capture platforms, and immobilized reagent arrays. The PEG spacer promotes better presentation of the biotin group at the material interface, which can improve accessibility for streptavidin/avidin binding in heterogeneous formats such as microarrays, coated surfaces, and porous substrates. In molecular imaging and diagnostic reagent development contexts, this surface chemistry is often leveraged to anchor biotinylated components in a controlled orientation relative to the underlying support.

4. Enrichment and Pull-Down Workflows

Biotin-PEG2-alkyne is frequently applied as an affinity enrichment reagent to isolate tagged biomolecules after click-based installation of biotin onto azide-bearing targets. The resulting biotinylated conjugates can be captured on streptavidin or avidin matrices, facilitating efficient separation from complex mixtures and supporting workflows such as sample cleanup, fractionation, and verification of labeling density. Laboratories also use this reagent to standardize enrichment strategies across experiments, since the biotin handle provides a consistent capture mechanism compatible with many downstream analytical platforms.