Hypoxia-sensitive adjuvant loaded liposomes enhance the antimicrobial activity of azithromycin via phospholipase-triggered releasing for Pseudomonas aeruginosa biofilms eradication

Robust biofilms and the complex airway environment with thick sputum, local hypoxia and persistent inflammation induce the intractability of chronic pulmonary infections caused by Pseudomonas aeruginosa ( P. aeruginosa ). Herein, we proposed a type of antibiotic-adjuvant liposomes ( [email protected] ), co-incorporating azithromycin (AZI), adjuvant (2-nitroimidazole derivative, 6-NIH) and biofilm dispersant (nitric oxide donor, DETA NONOate). [email protected] possessing negatively-charged surface and good hydrophilicity could easily penetrate through the sputum layer, then disassembled triggered by overexpressed phospholipase A 2 (PLA 2 ) in the microenvironment around biofilms. Nitric oxide produced by DETA NONOate promoted P. aeruginosa biofilms dispersal. 6-NIH was reduced to 2-aminomidazole derivative (6-AIH) under a hypoxic condition, and hence acted as an AZI adjuvant to enhance the antibacterial activity of AZI. It was found that [email protected] could significantly eliminate mature P. aeruginosa biofilms, effectively kill dispersed bacteria, inhibit the metabolism of survivors and prevent P. aeruginosa adherence to airway epithelial cells, accordingly restrain recurrent infections. Additionally, [email protected] performed a remarkable advantage in killing AZI-resistant P. aeruginosa and removing their biofilms. In summary, [email protected] present a potential nano-strategy to treat stubborn pseudomonal pulmonary infections and overcome correlative drug resistance.