title: Surface charge-conversion polymeric nanoparticles for photodynamic treatment of urinary tract bacterial infections.
abstract: Urinary tract infections are typical bacterial infections which result in a number of economic burdens. With increasing antibiotic resistance, it is urgent that new approaches are explored that can eliminate pathogenic bacteria without inducing drug resistance. Antimicrobial photodynamic therapy (PDT) is a new promising tactic. It is a gentle in situ photochemical reaction in which a photosensitizer (PS) generates reactive oxygen species (ROS) under laser irradiation. In this work, we have demonstrated Chlorin e6 (Ce6) encapsulated charge-conversion polymeric nanoparticles (NPs) for efficiently targeting and killing pathogenic bacteria in a weakly acidic urinary tract infection environment. Owing to the surface charge conversion of NPs in an acidic environment, the NPs exhibited enhanced recognition for Gram-positive (ex. S. aureus) and Gram-negative (ex. E. coli) bacteria due to the charge interaction. Also, those NPs showed significant antibacterial efficacy in vitro with low cytotoxicity. The MIC value of NPs to E. coli is 17.91 μg ml(-1), compared with the free Ce6 value of 29.85 μg ml(-1). Finally, a mouse acute cystitis model was used to assess the photodynamic therapy effects in urinary tract infections. A significant decline (P < 0.05) in bacterial cells between NPs and free Ce6 occurred in urine after photodynamic therapy treatment. And the plated counting results revealed a remarkable bacterial cells drop (P < 0.05) in the sacrificed bladder tissue. Above all, this nanotechnology strategy opens a new door for the treatment of urinary tract infections with minimal side effects.
authors.affiliation: Department of Urology and State Key Laboratory of Cancer Biology, Xijing Hospital, Fourth Military Medical University (FMMU), NO.169 Changle Western Road, Xi'an, People's Republic of China.
authors.forename: Shijie
authors.initials: S
authors.lastname: Liu
authors.forename: Shenglin
authors.initials: S
authors.lastname: Qiao
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.forename: Guobin
authors.initials: G
authors.lastname: Qi
authors.forename: Yaoxin
authors.initials: Y
authors.lastname: Lin
authors.forename: Zengying
authors.initials: Z
authors.lastname: Qiao
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Chen
authors.initials: C
authors.lastname: Shao
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D051379:Mice; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D053758:Nanoparticles / Q000737:chemistry*; D010778:Photochemotherapy / Q000379:methods*; D000067996:RAW 264.7 Cells; D013499:Surface Properties; D014552:Urinary Tract Infections / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents