Cationization-Enhanced Type I and Type II ROS Generation for Photodynamic Treatment of Drug-Resistant Bacteria

Abstract

Photodynamic therapy as an emerging phototheranostic approach holds great potential for antibacterial treatment, but is limited by compromised reactive oxygen species (ROS) generation in an aggregate and hypoxic microenvironment. Herein, we report a molecular cationization approach to boost the ROS, especially type I ROS generation of aggregationinduced emission (AIE) photosensitizers for photodynamic treatment of drugresistant bacteria. Such cationization reinforces the electron-accepting ability of the cationic moiety, promotes intersystem crossing (ISC), and increases electron separation and transfer processes. The resultant CTBZPyI exhibits largely enhanced ROS generation ability with predominant hydroxyl radical generation over its neutral counterpart in aggregate. Moreover, cationization also confers CTBZPyI with the bacterial binding ability and a moderate bacterial inactivation ability in the dark. Further light irradiation leads to superb antibacterial performance, which largely promotes the healing process of a MRSA-infected wound. Such a cationization strategy is expected to be a general strategy for the design of highly effective type I photosensitizers for bacterial infection treatment.

Aggregation-induced emission photosensitizer-based photodynamic therapy in cancer: from chemical to clinical

“…The highly efficient generation of Type I ROS and excellent photothermal conversion ability are resourcefully integrated into these PQ-cored PSs to achieve Type I photodynamic and photothermal combined antitumor treatment. Other detailed studies on the photophysical and photochemical mechanisms of AIE-PSs provided a reference for the molecular design of AIE-PSs basing on the Type I mechanism [ 86 – 89 ].

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Type I Photosensitizers Based on Aggregation-Induced Emission: A Rising Star in Photodynamic Therapy

“…To date, diverse subcellular organelle-targeted type I AIE PSs-based anti-tumor systems have been exploited in succession [ 57 ]. For instance, Feng et al [ 58 ] developed a class of cationic AIE PSs possessing a specific tumor cell mitochondrial targeting feature to facilitate both type I and type II PDT. Zhao et al [ 48 ] reported two type I AIE PSs to obtain selective accumulation in the ER and effectively arouse ER-stress-mediated cell apoptosis and autophagy upon PDT, by producing highly oxidizing type I radicals under light illumination.…”

Aggregation-Induced Emission Artificial Enzyme (AIEzyme) with DNase-Like Activity: Imaging and Matrix Cleavage for Combating Bacterial Biofilm

“…26,[49][50][51] So, for general antibacterial methods based on AIEgens, the regular irradiation and dressing change are usually required. [52][53][54] As for the proposed anti-biofilm method based on AIEzymes (Figure 7a), the irradiation and the dressing change are not required, avoiding the frequent operations and the exogenous infection. Because the DNase-like activity of AIEzymes can continuously catalyze the hydrolyzation of eDNA in EPS without irradiation, AIEzymes can eliminate recurrence of biofilms and realize persistent anti-infection.…”