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  • Tetrazine-based cycloadditions: application to pretargeted live cell imaging.

Tetrazine-based cycloadditions: application to pretargeted live cell imaging.

Bioconjugate chemistry (2008-12-05)
Neal K Devaraj, Ralph Weissleder, Scott A Hilderbrand
ABSTRACT

Bioorthogonal tetrazine cycloadditions have been applied to live cell labeling. Tetrazines react irreversibly with the strained dienophile norbornene forming dihydropyrazine products and dinitrogen. The reaction is high yielding, selective, and fast in aqueous media. Her2/neu receptors on live human breast cancer cells were targeted with a monoclonal antibody modified with a norbornene. Tetrazines conjugated to a near-infrared fluorochrome selectively and rapidly label the pretargeted antibody in the presence of serum. These findings indicate that this chemistry is suitable for in vitro labeling experiments, and suggests that it may prove a useful strategy for in vivo pretargeted imaging under numerous modalities.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
(E)-Cyclooct-4-enol
Sigma-Aldrich
TCO PEG4 succinimidyl ester
Sigma-Aldrich
TCO-amine HCl salt
Sigma-Aldrich
(E)-Cyclooct-4-enyl 2,5-dioxo-1-pyrrolidinyl carbonate
Sigma-Aldrich
(4-(1,2,4,5-Tetrazin-3-yl)phenyl)methanamine hydrochloride, 95%
Sigma-Aldrich
5-Norbornene-2-acetic acid succinimidyl ester, 97%
Sigma-Aldrich
5-Norbornene-2-endo-acetic acid