An AIE-Active Cyclometalated Iridium(III) Photosensitizer for Selective Discrimination, Imaging, and Synergistic Elimination of Gram- Positive Bacteria

A platform integrating selective discrimination, imaging, and synergistic elimination of Gram-positive bacteria is urgently needed to address the problem of bacterial infection, especially those resulting from Gram-positive bacteria,. Aggregation-induced emission materials (AIEgens) have shown great promise for antimicrobial applications. Herein, three positively charged AIE-active cyclometalated iridium photosensitizers (Ir1-3) were rationally designed and synthesized. Selective discrimination and imaging of Gram-positive bacteria among Gram-positive bacteria, Gram-negative bacteria, and fungi were achieved with Ir1-3. Among three AIE-active cyclometalated iridium photosensitizers, Ir1 had the best antibacterial activity owing to the monoaromatic substituent of phenanthroline imidazole ligand to the main ligand, eliminating Gram-positive bacteria through its inherent antibacterial mechanism and bacterial photodynamic inactivation. Furthermore, Ir1 altered Gram-positive bacterial gene expression and was successfully applied to S. aureus-infected wound treatment. Due to the interaction between lipoteichoic acids (LTA) and our iridium-based AIEgens, our AIEgen photosensitizers realized selective discrimination, imaging, and synergistic elimination of Gram-positive bacteria. [GRAPHICS] .

Automated summary

This article discusses the urgent need for a platform integrating selective discrimination, imaging, and synergistic elimination of Gram-positive bacteria, and introduces aggregation-induced emission materials (AIEgens) as promising antimicrobial agents. Through rational design and synthesis, three positively charged AIE-active cyclometalated iridium photosensitizers were developed for selective discrimination and imaging of Gram-positive bacteria. One of the photosensitizers exhibited the best antibacterial activity and was successfully applied in the treatment of S. aureus-infected wounds. The interaction between our iridium-based AIEgens and the surface components of Gram-positive bacteria enables selective discrimination, imaging, and synergistic elimination.