Photoresponsive Vesicles Enabling Sequential Release of Nitric Oxide (NO) and Gentamicin for Efficient Biofilm Eradication.

The development of new antibacterial agents that can efficiently eradicate biofilms is of crucial importance to combat persistent and chronic bacterial infections. Herein, the fabrication of photoresponsive vesicles capable of the sequential release of nitric oxide (NO) and gentamicin sulfate (GS) is reported, which can not only efficiently disperse Pseudomonas aeruginosa (P. aeruginosa) PAO1 biofilm but also kill the planktonic bacteria. Well-defined amphiphilic diblockcopolymers of poly(ethylene oxide)-b-poly(4-((2-nitrobenzyl)(nitroso)amino)benzyl methacrylate) (PNO) is first synthesized through atom transfer radical polymerization (ATRP). The PNO diblock copolymer self-assembled into vesicles in aqueous solution, and a hydrophilic antibiotic of GS is subsequently encapsulated into the aqueous lumens of vesicles. The vesicles undergo visible light-mediated N-NO cleavage, releasing NO and disintegrating the vesicles with the release of the GS payload. The sequential release of NO and GS efficiently eradicate P. aeruginosa PAO1 biofilm and kill the liberated bacteria, showing a better antibiofilm effect than that of NO or GS alone.