ZnO Nanorods with High Photocatalytic and Antibacterial Activity under Solar Light Irradiation

Abstract

ZnO nanorods (NRs) with an average length and diameter of 186 and 20 nm, respectively, were prepared through a mild solvothermal route and used as photocatalysts either as dispersed powder or immobilized on glass slides. The ZnO NRs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Dispersed ZnO NRs and, to a lesser extent, immobilized ZnO NRs were demonstrated to exhibit high photocatalytic activity under simulated sunlight of low intensity (5.5 mW/cm2) both for the degradation of the Orange II dye and for Escherichia coli bacterial decontamination (2.5-fold survival decrease after 180 min irradiation for immobilized NRs). SEM, atomic force microscopy (AFM), fluorescence spectroscopy, and epifluorescence microscopy demonstrate that cell surface damages are responsible of bacterial inactivation. The immobilized ZnO NRs could be reused up to five times for bacterial decontamination at comparable efficiency and therefore have great potential for real environmental applications.

An approach to the photocatalytic mechanism in the TiO2-nanomaterials microorganism interface for the control of infectious processes

“…In this regard, the 4-Log (99.99%) inactivation is typically required to achieve a quality of drinking water. However, most of the tests carried out so far on photoinactivation of microorganisms have been carried out on samples previously dried in the air, which greatly impairs their conservation [204,205,206,207]. The activity of TiO2 films after 6 h of illumination has shown a 100% antiviral effect against herpes simplex [201].…”

“…The resistance is associated with the viral J o u r n a l P r e -p r o o f characteristic, because as is well-known, a pathogenic characteristic of the virus is the induction of oxidative stress that breaks the intracellular redox balance. [204,206,207,208] No previous work has directly detected ROS activity, with the exception of one study that discard another possible mechanism by adding H2O2 to the experimental system.…”

Bacterial Lysis via Photocatalysis ‐ A Critical Mechanistic Review

“…SEM, TEM, AFM are used to visualize the effect of such nanomaterials on the bacterial cell wall. However, characterizations of such bacterial cells are given extra care for the sample preparation because of the destruction of the bacterial cells under high vacuum conditions.…”

“…The fluorescence is highly sensitive to the local environment and change in its conformation. The change in fluorescence intensity shows the change in the local environment, the conformal changes in the protein, i. e. loss in colony count . This is also described as FRET (Förster resonance energy transfer).…”

“…Dyes SYBR green II and propidium iodide have different spectral characteristics. Propidium iodide tends to pass through the cells when there is a compromise with cell integrity . A quantitative normal distribution of population estimation is obtained after single cell analysis, when each cell is pass through the laser of certain wavelength and accordingly emit light .…”