Twisted‐Planar Molecular Engineering with Sonication‐Induced J‐Aggregation To Design Near‐Infrared J‐Aggregates for Enhanced Phototherapy

Abstract J‐aggregates show great promise in phototherapy, but are limited to specific molecular skeletons and poor molecular self‐assembly controllability. Herein, we report a twisted‐planar molecular strategy with sonication‐induced J‐aggregation to develop donor–acceptor (D–A) type J‐aggregates for phototherapy. With propeller aggregation‐induced emission (AIE) moieties as the twisted subunits and thiophene as the planar π‐bridge, the optimal twisted‐planar π‐interaction in MTSIC induces appropriate slip angle and J‐aggregates formation, redshifting the absorption from 624 nm to 790 nm. In contrast, shorter π‐planarity results in amorphous aggregates, and elongation promotes charge transfer (CT) coupled J‐aggregates. Sonication was demonstrated to be effective in controlling self‐assembly behaviors of MTSIC, which enables the transformation from amorphous aggregates to H‐intermediates, and finally to stable J‐aggregates. After encapsulation with lipid‐PEG, the resultant J‐dots show enhanced phototherapeutic effects over amorphous dots, including brightness, reactive oxygen species (ROS) generation, and photothermal conversion, delivering superior cancer phototherapy performance. This work not only advances D–A type J‐aggregates design but also provides a promising strategy for supramolecular assembly development.