CBT‐Cys click reaction for optical bioimaging in vivo

Derived from the D-luciferin regeneration pathway in firefly body, click condensation reaction between 2-cyanobenzothiazole (CBT) and D-cysteine (Cys) (CBT-Cys reaction) possesses unique advantages, including superior biocompatibility, high second order rate, metal-free mild conditions, emerging as a powerful bioorthogonal tool for variety of chemical biological applications. Moreover, owing to its programmable controllability (e.g., pH, reduction, or enzyme), CBT-Cys is exploited fabricate stimuli-activatable imaging probes with self-assembling behaviors physiological context. At stimuli-rich pathological lesions interest, these undergo form cyclic dimers/oligomers linear polymers, further self-assemble into nanostructures. The situ formed nanostructures promote selective accumulation retention agent cargos at lesions, thus enabling precise enhanced vivo diseases (especially tumors). To address significance recent breakthroughs smart optical tumors/other diseases, we herein propose this mini-review, which advances (particularly 5 years) potential challenges (or chances) field are emphasized.