Covalent organic frameworks: Advancing antimicrobial photodynamic therapy for next-generation treatments

Abstract

Covalent organic frameworks (COFs) have gained significant attention in recent years, due to their tuneable properties and numerous applications, including their suitability as antimicrobial materials. The growth in antimicrobial resistance (AMR) in recent years is alarming, with 10 million deaths projected annually by 2050. Novel approaches to address AMR are urgently required, with this review focussing on recent developments on the suitability of COFs as novel antimicrobial photodynamic therapeutic agents. A particular emphasis is placed on their properties, including large surface area, tuneable porosity, and the flexibility of incorporating various functional groups that may improve photodynamic therapy (PDT). Incorporation of photosensitisers into a COF framework, can be used to create a scaffold that produces reactive oxygen species (ROS) under light activation and subsequently destroys microbial cells. This review systematically reviews the synthesis and functionalisation of COFs and evaluates their properties and practical applications in antimicrobial PDT. In addition, new approaches to address existing issues in the current literature including biocompatibility and the size of COF based PDT systems are proposed.