TCO-PEG3-TCO | CAS 2243569-22-2

TCO-PEG3-TCO is a bifunctional, polyethylene glycol–spaced trans-cyclooctene (TCO) click chemistry reagent designed for strain-promoted inverse electron-demand cycloaddition (SPIEDAC). The molecule presents two TCO handles for rapid, catalyst-free conjugation to complementary tetrazine partners, enabling efficient multivalent labeling and crosslinking in chemical biology and materials workflows. Its PEG3 linker supports water compatibility and helps preserve accessibility of reactive groups on biomolecules, polymers, and imaging scaffolds.

1. Multivalent Tetrazine Labeling

TCO-PEG3-TCO is widely used to build multivalent conjugates with tetrazine-containing probes, improving labeling density on surfaces and macromolecular carriers used in chemical biology research. The PEG3 spacer and dual TCO functionality support sequential or one-step attachment strategies where two tetrazine sites (or tetrazine-bearing components) can be engaged to generate higher avidity probe architectures for microscopy, flow-based assays, and analytical characterization. Researchers commonly select TCO-PEG3-TCO when they need robust, reproducible coupling of modular imaging or affinity reagents while maintaining aqueous handling and minimizing aggregation-prone conjugates.

2. Biomolecule Crosslinking Platforms

TCO-PEG3-TCO serves as a practical crosslinker precursor for constructing tetrazine-reactive biomolecule networks, including protein–protein and protein–polymer assemblies used in biomaterials science. The dual TCO groups enable formation of defined linkages between tetrazine-functional partners, supporting the generation of stable, modular conjugate frameworks for studying structure–function relationships and for creating tunable scaffold materials. In downstream workflows, TCO-PEG3-TCO is selected to introduce controlled spacing and to facilitate conjugation under mild, catalyst-free conditions that are compatible with many sensitive research-grade biomolecule formats.

3. Molecular Imaging Probe Construction

TCO-PEG3-TCO is commonly incorporated into molecular imaging and diagnostic reagent development pipelines where tetrazine-bearing reporters are assembled into conjugated probe formats for fluorescence, luminescence, or other label-based detection modalities. The bifunctional TCO design supports rapid assembly of probe constructs with defined valency, which is valuable when optimizing signal distribution across multicomponent imaging reagents. By providing a PEG3-separated dual reactive motif, TCO-PEG3-TCO helps maintain accessibility of the imaging handle and supports consistent conjugate architectures for instrument-ready probe preparation.

4. Polymer and Surface Functionalization

TCO-PEG3-TCO is used to functionalize polymers and material surfaces with reactive TCO moieties prior to tetrazine-based coupling, enabling construction of advanced coatings, bead-based assays, and engineered material interfaces. The PEG3 spacer improves compatibility with aqueous processing and can reduce steric hindrance compared with more compact linkers, supporting uniform attachment of tetrazine partners during material fabrication. Teams in materials chemistry and chemical engineering often rely on TCO-PEG3-TCO to generate modular, click-reactive surfaces that can be further decorated with fluorescent tags, affinity ligands, or other tetrazine-functional components for analytical and research instrumentation workflows.