Activatable NIR Schaap's 1,2-Dioxetane-Based Chemiluminescent Probes for Bioimaging Applications

Owing to the elimination of autofluorescence caused by real-time excitation with the external light source, chemiluminescent imaging possesses the advantages of improved signal-to-noise ratio and enhanced deep-tissue penetration. As an essential tool in optical imaging, near-infrared (NIR) chemiluminescent probes have attracted significant interest due to their superior tissue penetration depth and minimized light scattering. Molecular engineering that employs chemiluminescence resonance energy transfer (CRET) or extends conjugation of the original chemiluminescent (CL) molecule skeleton provides ways to extend CL emission into the NIR region. Compared with CL probes such as luminol or peroxyoxalates, Schaap's 1,2-dioxetane-based probes possess advantages of facile synthesis and modification and can be activated by diverse biomarkers, facilitating biological imaging. In this review, we begin with the molecular design strategies of NIR chemiluminescent probes, followed by their bioimaging applications for disease theranostics. Finally, existing challenges and future perspectives on NIR chemiluminescence imaging are discussed.