TCO-PEG8-NHS ester | CAS 2353409-95-5

TCO-PEG8-NHS ester is a trans-cyclooctene (TCO) functionalized PEG linker bearing an NHS ester for efficient conjugation to primary amines. As a click chemistry reagent, it is widely used in strain-promoted inverse electron-demand cycloaddition (SPIEDAC) workflows, where TCO serves as the strained alkene handle for rapid reaction with complementary tetrazines. The PEG8 spacer and NHS reactivity make it particularly useful for preparing stable, well-defined TCO-bearing bioconjugates for downstream labeling, imaging, and material functionalization in chemical biology and molecular imaging research.

1. Amine-Targeted Bioconjugation

TCO-PEG8-NHS ester is commonly used to introduce TCO moieties onto proteins, peptides, antibodies, and other amine-containing biomolecules via NHS ester chemistry. Researchers and diagnostic reagent developers rely on this format to generate tetrazine-reactive conjugates with improved solubility and reduced steric constraints due to the PEG8 spacer. The resulting TCO-labeled biomolecules are frequently used as modular building blocks for subsequent tetrazine-based click labeling, enabling streamlined workflows for probe generation and multistep assay development.

2. Tetrazine-Based Probe Labeling

TCO-PEG8-NHS ester is well suited for creating TCO-functional intermediates that can be rapidly clicked with tetrazine probes such as fluorescent dyes, affinity tags, or imaging reporters. This application is especially common in molecular imaging and chemical biology laboratories, where fast, bioorthogonal conjugation is valuable for preparing labeled targets under mild conditions. The PEG8 linker helps maintain accessibility of the strained alkene for efficient coupling to tetrazines, supporting consistent labeling of complex biomolecular systems used in research-grade imaging and detection reagent pipelines.

3. Surface and Material Functionalization

TCO-PEG8-NHS ester is frequently employed to functionalize amine-present surfaces and polymeric materials, including PEGylated coatings and biomaterial scaffolds, to create tetrazine-reactive interfaces. Materials scientists use this reagent to immobilize TCO handles on substrates for subsequent patterning, assembly, or labeling with tetrazine-bearing components, including fluorescent markers and affinity ligands. The combination of NHS reactivity and the PEG8 spacer supports robust surface coupling while helping preserve the accessibility of the click handle for downstream conjugation steps in materials and diagnostics research.

4. Multivalent Conjugate Construction

TCO-PEG8-NHS ester is used to build multivalent conjugates by installing multiple TCO groups on a single macromolecule or carrier, which can then be clicked with tetrazine-functional partners to generate higher-order constructs. In chemical biology workflows, this approach is valuable for creating densely labeled probes or scaffolded reagents where spatial arrangement and linker length influence performance in assay development. The PEG8 tether provides flexibility that can improve presentation of the strained alkene for efficient tetrazine coupling during construct assembly.