Antimicrobial photodynamic therapy to kill Gram-negative bacteria

Area of Science:

• Photochemistry
• Microbiology
• Biotechnology

Background:

• Antimicrobial resistance necessitates novel therapeutic strategies beyond traditional antibiotics.
• Gram-negative bacteria pose significant challenges due to their impermeable outer membrane.
• Photodynamic therapy (PDT) and photodynamic inactivation (PDI) are emerging as effective antimicrobial approaches.

Purpose of the Study:

• To review recent advancements in PDT/PDI for eradicating Gram-negative bacteria.
• To explore various photosensitizers (PS) and their mechanisms of action.
• To cover relevant patents and laboratory models for antimicrobial PDT.

Main Methods:

• Review of peer-reviewed articles and patents on PDT/PDI for Gram-negative bacteria.
• Categorization of photosensitizers by type (e.g., dyes, tetrapyrroles, nanoparticles).
• Inclusion of studies on targeting strategies and permeabilizing agents.

Main Results:

• PDT/PDI effectively inactivates Gram-negative bacteria like Pseudomonas aeruginosa.
• Diverse photosensitizers, including natural dyes, synthetic dyes, and nanoparticles, show efficacy.
• Formulations and adjuncts enhance PS delivery and bacterial inactivation.

Conclusions:

• Antimicrobial PDT/PDI is a viable strategy against Gram-negative bacterial infections.
• The development of novel photosensitizers and delivery systems is advancing the field.
• PDT/PDI presents an alternative to antibiotics with a lower risk of resistance development.