Photodynamic treatment of pathogens

Abstract The current viral pandemic has highlighted the compelling need for effective and versatile treatments, that can be quickly tuned to tackle new threats, are robust against mutations. Development of such treatments is made even more urgent in view decreasing effectiveness antibiotics, makes microbial infections next emerging global threat. Photodynamic effect one method. It relies on physical processes proceeding from excited states particular organic molecules, called photosensitizers, generated upon absorption visible or near infrared light. these tailored undergo efficient intersystem crossing, interact with molecular oxygen generate short lived reactive species (ROS), mostly singlet oxygen. These highly cytotoxic through non-specific oxidation reactions constitute basis treatment. In spite apparent simplicity principle, method still face important challenges. For instance, lifetime ROS means photosensitizer must reach target within a few tens nanometers, which requires proper engineering at nanoscale level. Photoactive nanostructures thus engineered should ideally comprise functionality turns system into theranostic means, introduction fluorophores suitable nanoscopy. We discuss principles strategies have been being explored antimicrobial antiviral photodynamic