Electrophoretically Deposited Layers of Octahedral Molybdenum Cluster Complexes: A Promising Coating for Mitigation of Pathogenic Bacterial Biofilms under Blue Light

Abstract

The fight against infective microorganisms is becoming a worldwide priority due to serious concerns about the rising numbers of drug-resistant pathogenic bacteria. In this context, the inactivation of pathogens by singlet oxygen, O 2 ( 1 Δ g ), produced by photosensitizers upon light irradiation has become an attractive strategy to combat drug-resistant microbes. To achieve this goal, we electrophoretically deposited O 2 ( 1 Δ g )-photosensitizing octahedral molybdenum cluster complexes on indium-tin oxide coated glass plates. This procedure led to the first example of molecular photosensitizer layers able to photoinactivate bacterial biofilms. We delineated the morphology, composition, luminescence, and singlet oxygen formation of these layers and correlated these features with their antibacterial activity. Clearly, continuous 460 nm light irradiation imparted the layers with strong antibacterial properties, and the activity of these layers inhibited the biofilm formation and eradicated mature biofilms of Gram-positive Staphylococcus aureus and Enterococcus faecalis, as well as, Gram-negative Pseudomonas aeruginosa and Escherichia coli bacterial strains. Overall, the microstructure-related oxygen diffusivity of the layers and the water stability of the complexes were the most critical parameters for the efficient and durable use. These photoactive layers are attractive for the design of antibacterial surfaces

Hafnium Oxide Nanostructured Thin Films: Electrophoretic Deposition Process and DUV Photolithography Patterning

“…Electrophoretic deposition is an attractive colloidal process offering short operation times, high deposition rates, versatility in the thickness and morphology of the deposited layer and scalability in terms of surface size and production volume. EPD has already successfully been used to deposit oxide nanoparticles, sulfide nanoparticles, metal nanoclusters and carbon nanotube thin films on a variety of substrates, sometimes followed by thermal treatment to improve adhesion [ 32 , 33 , 34 , 35 , 36 , 37 ]. The principal driving force in EPD is the charge of the colloidal particles, whose migration under an applied electric field, leads to the deposition of a homogeneous film.…”

Violet‐blue Light Induces “Natural” Photodynamic Plasma Disinfection with Endogenous Sensitizers

“…This is meant to be a play on words in that the 405 nm light can penetrate deeper into the plasma sample than UVA?C light. There are other examples of success with violet and blue light in microbe inactivation (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Even other examples are emerging with violet-blue or blue light in synthetic organic (22)(23)(24)(25)(26)(27)(28) and photopolymerization reactions (29), and naturally, there is a history of blue light therapy in neonatal jaundice (30)(31)(32)(33).…”

Universal “Three-in-One” Matrix to Maximize Reactive Oxygen Species Generation from Food and Drug Administration-Approved Photosensitizers for Photodynamic Inactivation of Biofilms

“…Photodynamic inactivation (PDI) is a promising approach for killing of a wide spectrum of microorganisms, which relies on the destructive role of reactive oxygen species (ROS) generated from photosensitizers (PSs). − To this regard, a series of PSs have been approved by US Food and Drug Administration (FDA). , However, due to the increased drug resistance of biofilms, new challenges for PSs are raised, particularly the generation efficiency of ROS. According to the Jablonski diagram, ROS generation is associated with the activated triplet states of PSs.…”