The antimicrobial activity of prepared hybrids
Photo-induced antimicrobial action of hybrids governs reactive oxygen species (ROS), i.e., hydroxyl radicals (•OH), superoxide radical anions (O2−•), and hydrogen peroxide (H2O2), with pronounced oxidation ability. These reactive species participate in antimicrobial action and photocatalytic oxidative reactions. Because they can form reactive oxygen species (ROS), biologically important polyphenols extracted from the plant, such as dihydroquercetin and epigallocatechin gallate, have antioxidative and antibacterial characteristics. Also, there is a synergism in killing bacteria when polyphenols and antibiotics are combined. However, we intend to use visible-light-responsive hybrids instead of antibiotics-polyphenol systems and achieve a synergism between the biocidal ability of organic components (polyphenols) and the light-induced biocidal action of the entire nanocomposites.
There are several advantages of using functionalized metal oxides with biologically active polyphenols supported by macroporous copolymers, such as (a) replacement of harmful UV light sources with less expensive Vis light sources, (b) avoiding environmental hazards due to the release of heavy metal ions and (c) extended use. We will test the toxic action of prepared hybrid materials using a variety of microbial species, such as Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis), and fungi (Candida albicans) in two sets of experiments. One set of experiments will be carried out under the static condition, while in the second one, we will use a homemade flow system to mimic devices for wastewater disinfection treatment. The concentration- and time-dependent antimicrobial ability in static conditions, under the monochromatic or white-light excitations of hybrids, will provide the necessary parameters to perform the dynamic experiments.