Photodynamic antimicrobial surfaces

Photodynamic therapy (PDT) is a therapeutic approach based on the synergistic action of three per se virtually harmless components: visible light, molecular oxygen and photosensitising drugs. The administration of the photosensitiser and subsequent irradiation of the target area with light of suitable wavelength/intensity result in the generation of reactive oxygen species (ROS), which damage subcellular structures and lead to cell death. Since its inception, PDT has been successfully applied to the treatment of several conditions, including cancers, precancerous conditions and microbial infections, receiving several clinical approvals worldwide.(a) In particular, the interest in antimicrobial applications of the photodynamic approach has been growing exponentially over the last couple of decades. Two key advantages of the use of PDT as an antimicrobial tool are the broad spectrum of action and the low potential of inducing resistance in microbes, both of which are due to the ability of ROS to inflict damage in a non-specific fashion.(b)

The fact that the damage to the microbial cell is inflicted by ROS rather than by the photosensitising drug itself, prompted the scientific community to design and develop photodynamic antimicrobial surfaces.(2) In this approach, a photosensitiser is associated to a suitable material to achieve surfaces that can be sterilised or decontaminated using light. This talk will survey different applications of photodynamic antimicrobial surfaces, ranging from medicine, healthcare environment, water remediation, food decontamination.

(a)    T. J. Dougherty, J. Clin. Laser Med. Surgery, 2002, 20, 3-7.

(b)    Wainwright M, Maisch T, Nonell S, Plaetzer K, Almeida A, Tegos GP, et al., The Lancet Infectious Diseases. 2017, 17, 49–55.

(c)     Dube E., Microorganisms, 2024, 12, 1573.