Copper(ii) complexes with porphyrins for photodynamic elimination of drug-resistant pathogens

Antimicrobial photodynamic therapy (aPDT) has become a promising solution for combating drug-resistant bacterial infections. However, the range of available photosensitizers for aPDT is still limited, and there is a clear need for the development of novel and more effective photosensitizers. Porphyrins have emerged as strong candidates for developing efficient photosensitizers. Additionally, copper complexes are recognized for their strong photodynamic therapy effects and biocompatibility. In this study, to improve the efficacy of photosensitizers, the copper porphyrin complex meso-tetrakis(4-chlorophenyl)porphyrin-Cu(II) (CuTCPP) was assessed for its aPDT activities against methicillin-resistant Staphylococcus aureus (MRSA). Our data show that CuTCPP-mediated aPDT has remarkable antibacterial effects. Mechanistic studies indicate that CuTCPP-aPDT can induce ROS overproduction in MRSA, damage cell membranes, and inhibit ATP synthesis. Moreover, CuTCPP-aPDT effectively removes MRSA from biofilms, suppresses biofilm formation, as well as degrades established biofilms. In vivo experiments show that CuTCPP-aPDT obviously accelerates the healing of wounds on mouse skin. Our study sheds light on the development of innovative photosensitizers for aPDT.