Potassium Chloride Potentiates Chlorin e6-Mediated Antimicrobial Photodynamic Inactivation

Photodynamic therapy (PDT) is being researched as an alternative for the inactivation of antibiotic-resistant bacteria. Despite promising results, only a few clinical applications involve antimicrobial PDT (aPDT), particularly for localized infections. One of the main reasons for this slow transition into clinics is that the effectiveness of PDT may vary depending on the type of the bacteria, their strains, and the photosensitizing agent (PS) used. Therefore, methods to increase the efficacy of antimicrobial photodynamic inactivation protocols, including combining PSs with natural compounds and inorganic salts, is an active area of research. Previous research has shown that inorganic salts, such as sodium azide and potassium iodide, can potentiate the efficacy of aPDT. This is the first study that uses another inorganic salt, potassium chloride (KCl), to potentiate aPDT, and the results of this in vitro study revealed that chlorin e6 (Ce6)-mediated PDT can kill significantly more bacteria when combined with a non-toxic concentration of KCl.