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An effective strategy to engineer selective photodynamic agents to surmount bacterial‐infected diseases, especially Gram‐positive bacteria remains a great challenge. Herein, we developed two examples of compounds for a proof‐of‐concept study where reactive differences in reactive oxygen species (ROS) can induce selective ablation of Gram‐positive bacteria. Sulfur‐replaced phenoxazinium (NBS‐N) mainly generates a superoxide anion radical capable of selectively killing Gram‐positive bacteria, while selenium‐substituted phenoxazinium (NBSe‐N) has a higher generation of singlet oxygen that can kill both Gram‐positive and Gram‐negative bacteria. This difference was further evidenced by bacterial fluorescence imaging and morphological changes. Moreover, NBS‐N can also successfully heal the Gram‐positive bacteria‐infected wounds in mice. We believe that such reactive differences may pave a general way to design selective photodynamic agents for ablating Gram‐positive bacteria‐infected diseases.

Novel thiocarbonyl derivatives (NIS and CRNS) with excellent ROS generation abilities are synthesized and studied as potential photosensitizers for one- and two-photon excited photodynamic therapy. In particular, NIS-Me and CRNS...

Boron-dipyrromethene (BODIPY) dyes have aroused considerable interest in cancer theranostics over the past decade because of robust photochemical properties. Although a large number of BODIPY photosensitizers (PSs) containing heavy atoms have been reported, the development of heavy-atom-free BODIPY PSs for oncologic photodynamic therapy (PDT) has been limited mainly by the uncertainty in intersystem crossing (ISC) mechanisms, unbalanced phototoxic effectiveness and fluorescence quantum yields, and aggregation-caused quenching effects. In addition, the lack of extensive in vivo studies of heavy-atom-free BODIPY PSs continues to limit clinical application. Herein, novel heavy-atom-free BODIPY-phenoxazine triads (BDP-8/BDP-9) that generate efficient excited triplet states via radical pair intersystem crossing (RP-ISC) followed by triplet charge recombination were developed for use in fluorescence image-guided PDT. BDP-8/BDP-9 exhibited high molar absorption coefficients, prominent aggregation-induced emission, and excellent singlet oxygen generation capability upon light irradiation. The corresponding BODIPY nanoparticles (BDP-8/BDP-9 NPs) with bright red emission, considerable phototoxicity, and excellent tumor-targeting ability were simply prepared by encapsulating BDP-8/BDP-9 PSs in a polymeric matrix. More importantly, the results of both in vitro and in vivo experiments demonstrated the considerable potential of BDP-8 NPs for image-guided photodynamic cancer therapy. This study may inspire the development of potential BODIPY-based nanoagents for cancer theranostics.

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