LED-Driven Photodynamic Therapy for Antimicrobial Application

Abstract

The improper and widespread use of antibiotics has escalated antimicrobial resistance (AMR) into a global challenge. AMR, the capacity of microorganisms to withstand potent antibiotics via intrinsic or genetic adaptations, creates substantial obstacles in clinical practice. Microbial colonization on implant surfaces necessitates the development of adaptable, biocompatible, and “smart” materials for the tissue–biomaterial interface. In this study, a light-activated self-sterilizing alginate-based film was engineered via sol–gel process by incorporating a bis-iodo-substituted Boron-dipyrromethene (I₂-BODIPY) photosensitizer known for its high singlet-oxygen (¹O₂) quantum yield, stability, and photodynamic efficiency. The system was evaluated in terms of both its cytotoxicity toward mammalian cells and its antimicrobial activity against bacteria. In planktonic bacterial assays, gram positive Staphylococcus aureus (S. aureus) showed a rapid and pronounced loss of viability at 0.106–5 µM under 5 mW cm⁻² green LED irradiation. In contrast, Escherichia coli (E. coli) required higher treatment intensities, > 3log reductions observed under 10–15 mW cm⁻² irradiation at concentrations ≥5 µM. As for the film material, alginate was selected owing to its relevance in microbial growth settings and suitability for tissue engineering applications. Overall, the film was evaluated in vitro under representative conditions, resulted with >3-log reduction for S. aureus. These findings indicate that the I₂-BODIPY–integrated alginate film, via ROS-mediated photodynamic action, holds promise as a photosensitive, light-activated self-sterilizing platform for preventing implant-associated microbial infections.

Keywords

• Antimicrobial resistance
• Antimicrobial Photodynamic therapy
• Boron-dipyrromethene

Supporting Institution

Izmir Democracy University

Project Number

HIZDEP_MHF/2402

Ethical Statement

Ethics committee approval was not required for this study because of there was no study on animals or humans.

Thanks

This research was funded by Izmir Democracy University, grant number. HIZDEP_MHF/2402. The author gratefully thank Dr. Burcin Karabey, Dr. Muhammed Ucuncu and Yunus Emre Ersoy for their support.

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