Capsule Shedding and Membrane Binding Enhanced Photodynamic Killing of Gram-Negative Bacteria by a Unimolecular
Guobin Qi1, Yufu Tang1, Leilei Shi2
1Department of Chemical and Biomolecular Engineering, National University of Singapore (Singapore), 4 Engineering Drive 4, Singapore 117585.
Abstract:
The development of new antimicrobial agents to treat infections caused by Gram-negative bacteria is of paramount importance due to increased antibiotic resistance worldwide. Herein, we show that a water-soluble porphyrin-cored hyperbranched conjugated polyelectrolyte (PorHP) exhibits high photodynamic bactericidal activity against the Gram-negative bacteria tested, including a multidrug-resistant (MDR) pathogen, while demonstrating low cytotoxicity toward mammalian cells. Comprehensive analyses reveal that the antimicrobial activity of PorHP proceeds via a multimodal mechanism by effective bacterial capsule shedding, strong bacterial outer membrane binding, and singlet oxygen generation. Through this multimodal antimicrobial mechanism, PorHP displays significant performance for Gram-negative bacteria with >99.9% photodynamic killing efficacy. Overall, PorHP shows great potential as an antimicrobial agent in fighting the growing threat of Gram-negative bacteria.
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