TCO-PEG2-amine | CAS 2141981-87-3

TCO-PEG2-amine is a strained trans-cyclooctene (TCO) click handle bearing a short polyethylene glycol (PEG2) spacer and a terminal primary amine, designed for bioorthogonal tetrazine-mediated ligation. As a TCO-functionalized PEG amine, it is commonly used as a modular precursor for installing reactive TCO moieties onto surfaces, polymers, and biomolecules, enabling subsequent conjugation with tetrazine partners used in imaging, sensing, and labeling workflows. The PEG spacer supports aqueous compatibility and reduces steric effects, making TCO-PEG2-amine a practical building block for downstream conjugation and probe assembly.

1. Tetrazine Probe Labeling

TCO-PEG2-amine is widely used to prepare TCO-bearing labeling reagents for tetrazine-based click conjugation, where the amine functionality enables attachment to carriers such as proteins, peptides, and other amine-reactive scaffolds. Researchers incorporate TCO-PEG2-amine into probe construction strategies to generate defined conjugates that can be rapidly assembled with tetrazine-functional dyes, affinity reagents, or imaging reporters. The PEG2 spacer helps maintain probe accessibility in aqueous buffers, supporting efficient coupling in typical laboratory labeling workflows and enabling modular exchange of the tetrazine partner to tune signal modality.

2. Surface And Material Functionalization

TCO-PEG2-amine is used in biomaterials science and chemical surface engineering to introduce TCO groups onto polymer films, hydrogel networks, and functionalized surfaces that contain available coupling chemistries for amine-bearing linkers. The terminal amine supports straightforward incorporation into amide-forming or amine-reactive surface modification schemes, producing TCO-functional materials that can later be decorated with tetrazine-tagged components. This approach is commonly adopted in the development of clickable coatings for assay platforms, immobilized reagent surfaces, and materials intended for sequential reagent loading using tetrazine ligation as the final assembly step.

3. Antibody And Protein Conjugate Building

TCO-PEG2-amine is a practical reagent for constructing TCO-modified protein conjugates used in molecular imaging reagent development and research tool generation. The amine handle allows conjugation to protein scaffolds through common bioconjugation routes that target accessible lysine residues or amine-reactive intermediates, yielding TCO-functional antibodies, antibody fragments, and protein binders compatible with subsequent tetrazine click steps. The PEG2 linker contributes to improved solubility and reduced local crowding around the strained alkene, supporting consistent labeling behavior during probe assembly and enabling flexible pairing with different tetrazine-labeled reporters.

4. Molecular Imaging Reagent Assembly

TCO-PEG2-amine is used as a TCO-building block in the assembly of molecular imaging and diagnostic reagent platforms that rely on rapid tetrazine ligation for final probe formation. By installing the TCO moiety with a PEG2 spacer and an amine-functional terminus, teams can create intermediate TCO conjugates that are later combined with tetrazine-functional imaging tags to generate final imaging-ready constructs. This modular workflow is especially valuable when probe components are sourced separately, allowing late-stage conjugation to manage labeling logistics and to support consistent probe preparation across multi-reagent research programs.