Azide-PEG7-Tos | CAS 1418561-41-7

Azide-PEG7-Tos is a PEG-based azide click chemistry reagent bearing a tosylate leaving group, combining the high reactivity of an azide handle with a tunable, water-compatible PEG spacer. As a bifunctional scaffold, it is commonly used in bioorthogonal labeling workflows and polymer or surface functionalization strategies where azide-bearing intermediates must be coupled to alkyne partners. The PEG7 length and tosylate functionality support practical downstream conjugation and immobilization steps in chemical biology, biomaterials, and imaging reagent development.

1. Bioorthogonal Probe Labeling

Azide-PEG7-Tos is widely used as an azide-bearing linker for assembling fluorescent, affinity, or mass-tag probes that require subsequent coupling to cyclooctyne or strained alkyne partners in live-cell compatible labeling workflows. The PEG7 spacer helps maintain probe solubility and reduces steric constraints during conjugate formation, which is particularly valuable when attaching labels to biomolecules such as proteins, peptides, and nucleic-acid-binding reagents. In many research settings, Azide-PEG7-Tos serves as a modular intermediate that can be incorporated into probe libraries for systematic evaluation of labeling density and linker length effects.

2. Surface and Material Functionalization

Azide-PEG7-Tos is used to introduce azide functionality onto polymeric materials, nanoparticles, and solid supports for downstream click immobilization and patterned surface chemistry. The tosylate group enables practical attachment to amine-containing surfaces or substrates, while the PEG7 chain provides a hydrated interface that can improve accessibility of the azide handle for subsequent coupling steps. This makes Azide-PEG7-Tos a common choice for preparing azide-functional coatings, affinity surfaces, and reusable diagnostic reagent platforms where controlled ligand presentation and antifouling-like behavior from PEG spacing are important.

3. Linker for PEGylated Conjugates

Azide-PEG7-Tos is frequently employed in conjugation design for constructing PEGylated bioconjugates and linker architectures that balance reactivity with colloidal stability. The reagent’s azide moiety provides a versatile click handle for attaching the final payload, while the PEG7 spacer supports solubility and spacing control between the conjugated partner and the reactive site. Azide-PEG7-Tos is therefore used in workflows that build multi-component constructs, including azide-tagged intermediates for assembling multi-ligand surfaces, modular affinity reagents, and reagent scaffolds used in molecular imaging and chemical biology toolkits.

4. Molecular Imaging Reagent Assembly

Azide-PEG7-Tos supports the preparation of imaging-oriented chemical probes by providing an azide functional handle for rapid conjugation to alkyne-bearing targeting motifs or reporter modules. The PEG7 linker is particularly useful when probe components must be kept dispersible and accessible, such as in fluorescent probe conjugates, luminescent tags, or other reporter systems that rely on efficient assembly of multi-part structures. In imaging reagent development pipelines, Azide-PEG7-Tos is often selected as a standardized linker to streamline the production of azide-functional intermediates that can be diversified by changing the alkyne partner.

5. Diagnostic and Affinity Reagent Building Blocks

Azide-PEG7-Tos is used to create azide-functional affinity reagents and diagnostic-relevant assay components that require modular assembly and consistent linker spacing. By enabling incorporation of an azide handle into probe formats, it facilitates subsequent click coupling to detection chemistries, capture ligands, or signal-generating modules. The PEG7 spacer helps maintain reagent performance in complex assay matrices by improving solubility and reducing non-specific interactions associated with overly rigid or short linkers, making Azide-PEG7-Tos a practical building block for constructing multi-component assay reagents and screening libraries.