Development of a high-level light-activated disinfectant for hard surfaces and medical devices

Photodynamic Inactivation of Opportunistic Premise Plumbing Pathogens and Their Biofilms

“…Photodynamic inactivation with MB and double exposure to light (670 nm) has been shown to work against older biofilms (48 h), as well as planktonic bacteria and younger biofilms (24 h) [129]. The disinfection potential of PDI for use on medical devices, shown with MB, has also been demonstrated with toluidine blue O (TBO), and when a nutrient germinant mixture was added to any of these two PSs, spore eradication was further improved, especially with TBO [130]. Photodynamic inactivation induced by TBO (5 µM) and blue light (400 nm, fluence rate 48 mW/cm 2 ), which is used to compare P. aeruginosa PAO1 wild type with isogenic variants (with different sensitivities to PDI), indicated the importance of a cell envelope and that quorum sensing is involved in response to photooxidative stress [131].…”

Photosensitiser-incorporated microparticles for photodynamic inactivation of bacteria

“…One such alternative is antimicrobial photodynamic therapy (aPDT). aPDT exploits the cytotoxic action of reactive oxygen species (ROS), such as singlet oxygen ( 1 O 2 ), produced upon light irradiation of photosensitiser (PS) molecules to destroy a range of microorganisms: vegetative bacteria, bacterial spores, antibiotic-resistant bacteria, biofilms, viruses and fungi [5][6][7][8][9][10][11]. Furthermore, the transient nature and indiscriminate multisite attack brought about by ROS, specifically 1 O 2 , makes it difficult for microorganisms to develop any protective mechanisms against these species and the development of microbial resistance against aPDT is unlikely [1,[12][13][14][15].…”

“…Initial aPDT studies primarily focused on investigating PS solutions, whereby the antimicrobial action relies on intracellular uptake of the PS by the target microorganism and can be useful for the treatment of various skin infections, or more recently for disinfection applications [7]. However, over recent years, the antimicrobial activity of surfaceimmobilised PSs has been explored, increasing the applicability of PSs to a wider range of areas, such as water disinfection to provide a reusable and durable antimicrobial system [18][19][20].…”

Past-expiration-date liquid disinfectants to deactivate biological and chemical toxins on building material surfaces

“…[6][7][8] Several decontamination technologies have been proposed in the past, and different sporicidal treatments have been developed. Strong acids disrupt spore integrity; 9,10 quaternary ammonia and other chemicals damage the inner membrane of the spores 11,12 and peroxides disrupt the spore germination apparatus by targeting key proteins. 13,14 The choice of a decontamination treatment depends on the use of technology, the biocide efficiency of the treatment, the type of the contaminated surface, and the basic materials needed for decontamination.…”