Synthesis of Photosensitizers Based on Tetrapyrrolic Macrocycles for Combination with Antibiotics: Dual Inactivation of Bacteria

The combination of photodynamic therapy with antibiotics or antimicrobial peptides for inactivation of bacteria is an area of growing interest due to the synergistic effect already observed by many authors. It has been shown that the efficiency of this dual antimicrobial therapy is highly dependent on the structure of the photosensitizer, being tetrapyrrolic macrocycles the ones with most promising results. There are a few review articles in the recent literature describing the main microbiological results concerning this dual inactivation of bacteria, but none of them focus on the synthetic processes of these photosensitizers and their remarkable chemical versatility. Therefore, herein we present an overview on synthetic methodologies for preparation of tetrapyrrolic macrocycles and their conjugates with antibiotics or antimicrobial peptides, for use in dual inactivation of bacteria. This review will be divided in two sections concerning the physical or covalent combinations of PS with antibiotic/cationic peptides, followed by brief critical analysis on their corresponding antimicrobial outcomes.

Automated summary

The combination of photodynamic therapy with antibiotics or antimicrobial peptides for bacteria inactivation has shown a synergistic effect. Tetrapyrrolic macrocycles have been found to be the most promising photosensitizers. While there are review articles on the microbiological results of this dual inactivation, none of them focus on the synthetic processes and chemical versatility of these photosensitizers. Therefore, this review presents an overview on synthetic methodologies of tetrapyrrolic macrocycles and their conjugates with antibiotics or antimicrobial peptides, for use in dual bacteria inactivation.