Advances on antimicrobial photodynamic inactivation mediated by Zn(II) porphyrins

Over the years, microorganisms have developed several resistance mechanisms against standard treatments, thus limiting the effect of drugs and rendering ineffective therapies. Considering the growing number of resistant pathogens and adverse effects of conventional therapies, new antimicrobial technologies able to provide more effective, rapid, and safer treatments to inactivate pathogens, with unlikely chances of inducing resistance, are needed. In this regard, antimicrobial photodynamic inactivation (aPDI) has emerged as an alternative modality of treatment. In particular, Zn(II) porphyrins (ZnPs) hold great potential as photosensitizers (PSs) for aPDI and have been attracting increasing attention. The chemical structure of ZnPs can be tailored to produce PSs with improved chemical stability and photophysical properties, also modulating their amphiphilic and ionic characters, bioavailability, and (sub)cellular distribution. Thus, in this review, we provide a detailed report of studies published in about the last 10 years (2010-2021) focusing on aPDI mediated by ZnPs over a variety of pathogens, including bacteria, fungi, viruses, and protozoa. Fundamentals of aPDI, and porphyrin and its derivatives, especially ZnPs, are also included herein. We hope that this review can guide and be a reference for future studies related to aPDI mediated by ZnPs, and encourages more detailed studies on ZnP photophysical and photochemical properties, aiming to improve the fight against infectious diseases.

Automated summary

Studies suggest that new antimicrobial technologies are needed to combat the increasing number of resistant pathogens due to the development of resistance mechanisms. Zn(II) porphyrins have emerged as promising photosensitizers for antimicrobial photodynamic inactivation, offering improved chemical stability and photophysical properties. This review provides a comprehensive overview of studies focusing on aPDI mediated by ZnPs against various pathogens, highlighting the potential for further research on ZnP photophysical and photochemical properties.