Because of the severe antibiotic resistance, photodynamic therapy is considered as a potent method for the treatment of bacterial infection with bare drug resistance. However, its therapeutic efficacy is not always satisfactory in practical treatment. In this study, pH-responsive prodrug micelles were prepared by conjugation of chlorin e6 to polyethylene glycol-b-poly(2-(hexamethyleneimino) ethyl methacrylate-co-aminoethyl methacrylate) for improving the antimicrobial activity of photodynamic therapy. The micelles were negatively charged in normal physiological environment, which was very important for long blood circulation. However, the micelles could turn to be positively charged in bacterial infection microenvironment and then adhere to negatively charged bacterial membranes, which could significantly improve their antibacterial activity against both methicillin-resistant Staphylococcus aureus and Escherichia coli after laser irradiation. The in vivo experiment showed excellent antibacterial effect of pH-sensitive micelles in a subcutaneous infection model. The micelles showed great potential in the photodynamic therapy of stubborn bacterial infections.

由于严重的抗生素耐药性，光动力疗法被认为是治疗具有裸药耐药性的细菌感染的有效方法。然而，其治疗功效在实际治疗中并不总是令人满意的。在这项研究中，pH响应的前药胶束是通过将二氢卟酚e6与聚乙二醇-b-聚（2-（六亚甲基亚氨基）甲基丙烯酸乙酯-co-甲基丙烯酸氨基乙酯），以改善光动力疗法的抗菌活性。在正常的生理环境中，胶束带负电，这对于长时间的血液循环非常重要。然而，胶束在细菌感染的微环境中可能带正电，然后粘附在带负电的细菌膜上，这可以显着提高激光照射后对耐甲氧西林的金黄色葡萄球菌和大肠杆菌的抗菌活性。在体内实验中显示出pH敏感性胶束在皮下感染模型优异的抗菌效果。胶束在顽固细菌感染的光动力治疗中显示出巨大潜力。