Insights into the Photocatalytic Bacterial Inactivation by Flower-Like Bi2WO6 under Solar or Visible Light, Through in Situ Monitoring and Determination of Reactive Oxygen Species (ROS)

Abstract

This study addresses the visible light-induced bacterial inactivation kinetics over a Bi2WO6 synthesized catalyst. The systematic investigation was undertaken with Bi2WO6 prepared by the complexation of Bi with acetic acid (carboxylate) leading to a flower-like morphology. The characterization of the as-prepared Bi2WO6 was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), specific surface area (SSA), and photoluminescence (PL). Under low intensity solar light (<48 mW/cm2), complete bacterial inactivation was achieved within two hours in the presence of the flower-like Bi2WO6, while under visible light, the synthesized catalyst performed better than commercial TiO2. The in situ interfacial charge transfer and local pH changes between Bi2WO6 and bacteria were monitored during the bacterial inactivation. Furthermore, the reactive oxygen species (ROS) were identified during Escherichia coli inactivation mediated by appropriate scavengers. The ROS tests alongside the morphological characteristics allowed the proposition of the mechanism for bacterial inactivation. Finally, recycling of the catalyst confirmed the stable nature of the catalyst presented in this study.

Conformational control of antimicrobial peptide amphiphilicity: consequences for boosting membrane interactions and antimicrobial effects of photocatalytic TiO2 nanoparticles

“…A similar effect was previously found for TiO 2 NPs coated with the AMP WWWKYE21 (8) and is likely due to diffuse light scattering by membrane-bound NPs deflecting some of the light, therefore resulting in less efficient ROS generation per particle at high local particle concentrations in the lipid bilayer (54,55). Similar effects have been reported previously in photocatalytic degradation of organic toxins (56), as well as for photolytic antibacterial effects (57,58). This concentration dependence indicates that there is a limit for how far binding of peptidecoated photocatalytic NPs can be used to boost photocatalytic degradation.…”

Preliminary Study on Light-Activated Antimicrobial Agents as Photocatalytic Method for Protection of Surfaces with Increased Risk of Infections

“…(2017) demonstrated, for the first time, the effectiveness of the light-activated antimicrobial surface against yeast, viruses, filamentous fungi, and fungus-like organisms [59]. Research results regarding the inactivation of Escherichia coli by photocatalysis involving TiO 2 nanoparticles alone or in transparent coatings (varnishes) were recently published [60,61]. The antibacterial activity of TiO 2 was evaluated through two types of experiments under UV irradiation: (i) in slurry with physiological water (stirred suspension); and (ii) in a drop deposited on a glass plate.…”

Synthesis of CuFe2O4‐Ti and CuFe2O4‐Ti‐GO nanocomposite photocatalysts using green‐synthesized CuFe2O4: determination of photocatalytic activity, bacteria inactivation and antibiotic degradation potentials under visible light

“…Both the Hom and nodified Hom model well‐fitted ( R 2 > 0.93 and R 2 > 0.97) the experimental findings and were mostly descriptive of the general inactivation trend (Figs 11 and S6). The OH ∙ was reported as the dominant E. coli inactivation mechanism in various research 76 Except for the case of CFT‐GO 3%, a prolonged delay of bacterial inactivation was pronounced and attributed mainly to the length of required time for OH ∙ species to diffuse into bacterial cells (Fig. 11 and Table 3).…”