Progress in bioorthogonal chemistry for prodrug activation and imaging

Conventional prodrug strategies, while innovative, are frequently hampered by off-target activation and systemic toxicity inherent to endogenous stimuli. Recently, bioorthogonal cleavage reactions have emerged as a significant alternative, utilizing exogenous and endogenous triggers to ensure high-fidelity in situ prodrug activation and release. Among these, the tetrazine-trans-cyclooctene (TZ-TCO) IEDDA reaction has emerged as a promising strategy for click-to-release prodrug activation. Furthermore, recent advances in transition-metal and photocatalytic systems have integrated drug activation with real-time imaging through simultaneous pro-fluorophore uncaging. This review systematically summarizes these bioorthogonal platforms and their dual therapeutic-diagnostic applications, providing a roadmap for their transition from experimental models to clinical practice. Furthermore, we offer perspectives on the future development of bioorthogonal prodrug activation.