Specific discrimination and synergistic elimination of Gram-positive bacteria by an aggregation-induced emission-active ruthenium (II) photosensitizer

The infections caused by Gram-positive bacteria (G+) have seriously endangered public heath due to their high morbidity and mortality. Therefore, it is urgent to develop a multifunctional system for selective recognition, imaging and efficient eradication of G+. Aggregation-induced emission materials (AIEgens) have shown great promise for microbial detection and antimicrobial therapy. In this paper, a multifunctional ruthenium (II) polypyridine complex Ru2 with aggregation-induced emission (AIE) characteristic, was developed and used for selective discrimination and synergistic extermination of G+ from other bacteria with unique selectivity. The selective G+ recognition benefited from the interaction between LTA and Ru2. Accumulation of Ru2 on G+ membrane turned on its AIE lumienscence and allowed specific G+ staining. Meanwhile, it also possessed robust antibacterial activity for G+ in vitro and in vivo antibacterial experiments attributing to the synergistic chemotherapeutic and photodynamic therapeutic effects. To the best of our knowledge, Ru2 is the first Ru-based AIEgen photosensitizer for simultaneous dual applications of G+ detection and treatment, and inspire the development of promising antibacterial agents in the future.