Multi-rotor imidazole-based fluorophores for rapid delineation of squamous cell carcinoma infiltration margins in murine surgical specimens

Multi-rotor imidazole derivatives have attracted more and more attention due to their unique electronic and photophysical properties as well as diverse applications. Combined with aggregation-induced emission (AIE) mechanism, multi-rotor imidazole core could also be functionalized as AIE luminogens (AIEgens). Herein, we report a novel family of AIEgens, designated as TPIT-X, which features a donor-π-acceptor (D-π-A) backbone wherein 1,4,5-triphenylimidazole serves as the donor and thiophene acts as the π-linker. By introducing appropriate acceptor units, we designed and synthesized TPIT-1 to TPIT-6, which exhibit tunable emission colors ranging from green (490 nm) to deep red (695 nm), covering nearly the entire visible spectrum. These molecules also display typical AIE characteristics, with up to 30-fold fluorescence enhancement. Taking advantage of their AIE feature, TPIT-6 nanoparticles conjugated with anti-EGFR antibodies successfully realized rapid determination of squamous cell carcinoma (SCC) tumor infiltration margins in ex vivo mouse surgical specimens, thereby positioning them as promising imaging agents for rapid intraoperative tumor biopsy during hand SCC resection.