Near-Infrared multifunctional theranostic agent with Wave-Like aggregates modulated by substituent position effect

Two isomorphic theranostic agents, named 6-TDE and 7-TDE, were designed and prepared by substituent position modification, exhibiting the grid-like and wave-like structure. Specially, 7-TDE possessed favorable ROS (Type I and Type II) as well as self-monitoring mitochondrial autophagy and multimodal imaging. [Display omitted] •Two interesting packing modes, the grid-like and wave-like structure through substituent position modification on packing mode. This study provides the new insight into the “Formula-Aggergete-Property” relationship of chemical structure.•A photosensitizer capable of photodynamic therapy (Type I and Type II) and self-monitoring mitochondrial autophagy.•The photosensitizer presented outstanding performance in multimodal imaging, including fluorescence imaging (FLI), photoacoustic imaging (PAI) and photothermal imaging (PTI). Precise design of organic photosensitizers (PSs) promoted the technological innovation for multimodal imaging-guided synergistic therapy. Nonetheless, various group substitution could not only optimize the basic photophysical behavior, but possibly change the aggregate, which handicaps the deep understanding of the “Formula-Aggergete-Property” relationship. Bearing this in mind, herein two isomers, named 6-TDE and 7-TDE, were prepared via substituting position modification. Among them, 6-TDE exhibited the grid-like structure, while 7-TDE presented wavy-like structure. Despite the aggregates were different, 6-TDE and 7-TDE shared common features including partly twisted backbone and non-overlapped-orbit, hence resulting in similar optical physical behavior such as decent extinction coefficient, near-IR emission, large stockes shifts, etc. Meanwhile, though two PSs could both generated Type-I and Type-II ROS, 7-TDE possessed smaller singlet–triplet splitting (ΔEST), which exhibited favorable ROS as well as outstanding mitochondrial targeting, achieving efficient photodynamic therapy (PDT) effect. During this process, mitochondrial autophagy could be tracked and observed effectively and in real-time. Moreover, 7-TDE presented outstanding performance in multimodal imaging, including fluorescence imaging (FLI), photoacousticimaging (PAI) and photothermal imaging (PTI). This study enriches the strategy of precise molecular engineering to optimize theranostic agents.