Tetrazine Building Blocks

AAT Bioquest offers a comprehensive selection of tetrazine building blocks for bioorthogonal click chemistry applications. Tetrazines react rapidly with trans-cyclooctene (TCO) groups via the inverse electron-demand Diels-Alder (iEDDA) reaction, providing one of the fastest bioconjugation methods available. This catalog includes fluorescent tetrazine dyes across the full visible and near-infrared spectrum, featuring AAT Bioquest's proprietary iFluor®, AATOM™, and XFD dye platforms alongside classic cyanine dyes.

Dye Series	Spectral Range	Key Advantages
iFluor®	488–647 nm	Superior brightness, excellent photostability
AATOM™	390–700 nm	Single-molecule detection
XFD	350–790 nm	Alexa Fluor® equivalent, full spectrum coverage
Cyanine (Cy)	555–801 nm	Classic dyes, NIR options (Cy7, Cy7.5)

Fig. 1

Schematic illustrating the strain‐promoted inverse‐electron‐demand Diels–Alder (iEDDA) reaction between a tetrazine–dye conjugate and a trans‐cyclooctene (TCO)–modified biomolecule. The tetrazine–dye selectively and rapidly reacts with the TCO moiety on the modified biomolecule to form a stable covalent linkage, enabling site-specific fluorescent labeling. This bioorthogonal “click chemistry” process is fast, selective, and well‐suited for biocompatible labeling applications.

iFluor® Tetrazine Dyes

iFluor® tetrazine dyes combine AAT Bioquest's proprietary high-performance fluorescent dyes with tetrazine click chemistry functionality. These dyes react with TCO-labeled biomolecules to provide exceptionally bright, photostable labeling for demanding imaging applications.

Superior brightness compared to traditional fluorophores (Alexa Fluor®, FITC equivalents)
Excellent photostability for extended imaging sessions and time-lapse microscopy
Optimized for common laser lines (488, 555, 594, 647 nm) used in confocal and flow cytometry
Water soluble with minimal non-specific binding
Fast iEDDA reaction enables efficient labeling in live cells

AATOM™ Tetrazine Dyes

AATOM™ tetrazine dyes provide excellent fluorophore performance with tetrazine functionality for TCO-reactive bioconjugation. This series offers exceptional coverage from UV to far-red wavelengths, making it ideal for FACS, FISH, and advanced fluorescence microscopy applications including super-resolution imaging.

18 wavelength options spanning 390–700 nm for comprehensive multiplexing
High quantum yields for bright signal intensity
Excellent photostability suitable for super-resolution microscopy (STORM, PALM)
Optimized for FACS and FISH applications
Sharp emission spectra minimize spectral bleed-through in multiplexed experiments

AATOM™ dyes are manufactured by AAT Bioquest and are not affiliated with ATTO-TEC GmbH.

XFD Tetrazine Dyes (Alexa Fluor® Replacements)

XFD tetrazine dyes offer Alexa Fluor® equivalent spectral properties with tetrazine click chemistry functionality. This comprehensive series provides the broadest wavelength coverage in our tetrazine portfolio, spanning from UV (350 nm) through near-infrared (790 nm), making it ideal for multicolor flow cytometry and fluorescence microscopy applications.

Alexa Fluor® equivalent spectra for seamless integration with existing protocols
20 wavelength options from 350–790 nm for maximum flexibility
Excellent water solubility for labeling in aqueous conditions
pH-insensitive fluorescence across physiological range
Compatible with standard filter sets for all major imaging platforms

Cyanine (Cy) Tetrazine Dyes

Cyanine tetrazine dyes feature classic Cy dye fluorophores with tetrazine functionality for TCO-based bioconjugation. This series includes standard Cy3, Cy5, and Cy3B dyes, as well as extended wavelength options (Cy5.5, Cy7, Cy7.5) for near-infrared imaging applications including in vivo studies.

Industry-standard Cy dyes with well-characterized spectral properties
NIR options (Cy7, Cy7.5) for deep tissue and in vivo imaging
Cy3B variants with enhanced brightness and photostability
PEG8 linker option (Cy3B PEG8) for improved solubility and reduced aggregation

Specialty Tetrazine Building Blocks

BAPTA tetrazine provides a unique non-fluorescent building block for introducing calcium chelation functionality into TCO-labeled biomolecules. This specialized reagent enables the development of custom calcium-sensitive probes and sensors.

Tetrazine-TCO Click Chemistry Overview

The inverse electron-demand Diels-Alder (IEDDA) reaction between tetrazines and trans-cyclooctenes (TCO) represents one of the fastest bioorthogonal reactions available, with rate constants up to 10⁶ M⁻¹s⁻¹. This exceptional speed enables rapid labeling even at low reagent concentrations.

Key Advantages of Tetrazine Building Blocks

Feature	Benefit
Ultrafast kinetics	Reactions complete in seconds to minutes, ideal for live-cell applications
No catalyst required	Eliminates cytotoxic copper, enabling in vivo applications
High selectivity	Minimal cross-reactivity with native biomolecules
Fluorogenic potential	Many tetrazine-functionalized dyes show fluorescence turn-on upon reaction
Physiological compatibility	Stable and reactive in aqueous buffers at neutral pH

This document (01.0324.251203r1) was last updated on Sat Feb 28 2026. All trademarks and registered trademarks mentioned herein are the property of their respective owners.