Biotin-PEG4-Alkyne | CAS 1262681-31-1

Biotin-PEG4-Alkyne is a biotinylated, PEG4-spaced terminal alkyne reagent designed for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry. The flexible PEG linker improves accessibility of the biotin handle on biomolecules, nanoparticles, and surfaces, enabling efficient conjugation to azide-functional partners while preserving binding competence. This reagent is widely used as a modular “clickable biotin” tool for labeling, affinity capture, and downstream assay development in chemical biology and biomaterials workflows.

1. Affinity Capture Labeling

Biotin-PEG4-Alkyne is commonly used to generate azide-tagged affinity probes where biotin needs to be installed at a defined position on a target scaffold. Researchers employ CuAAC to attach the reagent to azide-bearing proteins, peptides, antibodies, or polymeric constructs, producing conjugates that can be rapidly enriched using streptavidin or avidin reagents. The PEG4 spacer helps reduce steric shielding, which is particularly valuable when biotin is presented on crowded surfaces such as cell-surface mimics, extracellular vesicle preparations, or densely functionalized polymer particles. This makes Biotin-PEG4-Alkyne a practical choice for workflows that require robust capture and convenient detection through widely available biotin-binding reagents.

2. Surface Patterning And Coatings

Biotin-PEG4-Alkyne is frequently applied in biomaterials and materials chemistry to create biotin-functional interfaces via click coupling to azide-terminated coatings, self-assembled layers, or patterned substrates. By incorporating the alkyne into surface-accessible regions, teams can control spatial presentation of biotin for subsequent streptavidin-mediated assembly of proteins, enzymes, or nucleic-acid probes. The PEG4 linker contributes to improved accessibility of the biotin moiety at solid–liquid interfaces, which can otherwise limit binding when linkers are too short. Such surface patterning strategies are used to build reusable capture platforms, microarray formats, and biofunctional coatings for research-grade assay development and analytical workflows.

3. Imaging And Detection Probes

Biotin-PEG4-Alkyne supports the generation of detection-ready conjugates where biotin serves as a universal handle for fluorescent, enzymatic, or affinity-based readouts. In typical research workflows, azide-functional imaging agents, reporter constructs, or targeting ligands are clicked with Biotin-PEG4-Alkyne to introduce biotin at the stage most compatible with the experimental design. The PEG4 spacer helps maintain probe accessibility, which is important for consistent labeling density and for minimizing nonspecific steric effects that can occur with more rigid or shorter linkers. As a result, Biotin-PEG4-Alkyne is often selected when investigators need flexible coupling to diverse azide-bearing components while keeping downstream detection compatible with streptavidin/avidin-based reagents.

4. Proteomics And Pull-Down Workflows

Biotin-PEG4-Alkyne is widely used in proteomics and chemical biology for affinity enrichment and pull-down experiments following click-compatible labeling strategies. Researchers incorporate the reagent into azide-containing labeling schemes to introduce biotin onto complex protein mixtures, enabling selective isolation of modified species using streptavidin beads. The PEG4 spacing can improve recovery of biotinylated targets by reducing steric hindrance during bead binding and washing steps, which is beneficial when working with low-abundance proteins or partially modified samples. This application is particularly common in studies that require modular tagging of biomolecules for subsequent mass spectrometry sample preparation or targeted biochemical analysis.