Unprecedented natural mangiferin excimer induced aggregation-induced emission luminogens for highly selective bioimaging of cancer cells

Rational fabrication of simple aggregation-induced emission luminogens (AIEgens) with outstanding in vivo applications is still a challenging work. Most of the reported AIEgens included professional molecular design strategy and complex organic synthesis procedure. Herein, an unprecedented natural AIEgen, mangiferin, has been described, which was easily obtained from mango leaves. Detailed photophysical studies, crystallographic analysis, and theoretical calculations revealed that C-glucoside substitution of mangiferin resulted in the intermolecular hydrogen bonding to form stable and unique antiparallel dimer with J-type aggregates, and suppressed aromatic strong ππ stacking for effective and enhanced static excimer fluorescence with large Stokes shift in aggregate state. Moreover, mangiferin exhibited fascinating advantages, such as excellent biocompatibility, high photostability, and water solubility for bioimaging. Besides, docking calculations verified the recognition of mangiferin dimer by B-cell lymphoma 2 (Bcl-2) protein for cancer-cell mitochondria-targeted bioimaging. Impressively, mangiferin succeeded in distinguishing tumor tissues from normal tissues with high contrast after intravenously injection into mice. The present study consolidated an effective strategy for finding and fabrication of novel AIEgens, and demonstrated the new potential of mangiferin in clinical applications.