Effects of the Energy Delivery Rate on <i>Candida albicans</i> Eradication in Laser-based Photodynamic Therapy

Photodynamic therapy (PDT) is a recently studied non-invasive anticancer/antibacterial treatment that utilizes photosensitizers sensitive to both internal oxygen and external light. Candida vaginitis is caused by the overgrowth of yeast in the vaginal environment, with Candida albicans being the most common causative organism. Although antifungal agents are the standard treatment, the recurrence rates remain high. This study evaluated the effects of PDT using a diode laser combined with PhotoMed or Spirulina extract on the eradication of C. albicans and investigated the impact of the energy delivery rates on the treatment efficacy. The PhotoMed achieved a 100% eradication rate of C. albicans regardless of the energy delivery rate, highlighting its potent antimicrobial effects. In contrast, the Spirulina extract had no significant effects under identical conditions. These findings underscore the critical role of photosensitizer selection in the PDT outcomes and establish PhotoMed as a promising agent for treating C. albicans infections. In addition, a higher energy delivery rate of 6.2 mW/cm2 was found to be suitable, considering the time efficiency required for treating vaginal infections.