Methyltetrazine-PEG8-acid | CAS 2183440-33-5

Methyltetrazine-PEG8-acid is a PEG8-extended methyltetrazine click chemistry reagent designed for rapid tetrazine-mediated inverse electron-demand Diels–Alder (IEDDA) ligation with strained trans-cyclooctene or bicyclononyne partners. The reagent combines a reactive methyltetrazine handle for bioorthogonal conjugation with a hydrophilic PEG spacer that improves aqueous solubility and reduces steric constraints during labeling. The carboxylic acid functionality enables downstream coupling to activated surfaces, polymers, or biomolecule conjugation workflows, making it well-suited for constructing modular imaging and assay components.

1. Surface And Polymer Conjugation

Methyltetrazine-PEG8-acid is commonly used to functionalize polymeric materials and engineered surfaces with a stable, water-compatible tetrazine handle for subsequent click attachment of targeting ligands, reporters, or imaging tags. The PEG8 spacer helps maintain accessibility of the tetrazine moiety when immobilized on beads, membranes, or hydrogel matrices, supporting efficient downstream conjugation in complex buffer environments. The terminal acid group provides a practical anchor for standard coupling strategies to introduce tetrazine density onto material scaffolds used in assay development and molecular probe libraries.

2. Biomolecule Labeling Workflows

Methyltetrazine-PEG8-acid is applied in research workflows that require modular, bioorthogonal attachment of functional payloads to proteins, peptides, and other biomolecular constructs. The methyltetrazine moiety enables fast and selective ligation to cyclooctene/bicyclononyne-functional partners, while the PEG8 linker supports conjugation in aqueous systems where biomolecules are sensitive to aggregation and nonspecific interactions. The carboxylic acid functionality supports incorporation into established bioconjugation pipelines, enabling researchers to build multi-component probes by sequential click steps rather than relying on single-step labeling chemistries.

3. Molecular Imaging Probe Assembly

Methyltetrazine-PEG8-acid is frequently used as a key intermediate for assembling imaging and detection reagents that incorporate a tetrazine “reactive docking” site for later attachment of fluorophores, affinity handles, or imaging reporters. The PEG8 extension improves dispersion and reduces steric hindrance, which is particularly valuable when attaching bulky imaging moieties to macromolecular carriers or scaffolded probe architectures. By using the carboxylic acid handle to integrate the tetrazine unit into a probe scaffold, teams can generate versatile imaging constructs through iterative click conjugation, supporting rapid optimization of probe composition for instrument-compatible labeling formats.

4. Assay And Diagnostic Reagent Platforms

Methyltetrazine-PEG8-acid is well-suited for constructing assay reagent platforms that rely on orthogonal, high-yield assembly of detection components onto capture surfaces or reagent carriers. The tetrazine handle supports efficient pairing with strained alkenes/alkynes used to introduce signal-generating tags, enabling researchers to design modular workflows where capture elements and reporters are prepared separately and then combined by click ligation. The PEG8 spacer and terminal acid group help integrate the reagent into common diagnostic-reagent formats such as bead-based assays, immobilized reagent coatings, and multi-component test chemistries, improving reproducibility across batch-to-batch reagent preparation.