Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium

Abstract

Titania (TiO2)-based nanocomposites subjected to light excitation are remarkably effective in eliciting microbial death. However, the mechanism by which these materials induce microbial death and the effects that they have on microbes are poorly understood. Here, we assess the low dose radical-mediated TiO2 photocatalytic action of such nanocomposites and evaluate the genome/proteome-wide expression profiles of Pseudomonas aeruginosa PAO1 cells after two minutes of intervention. The results indicate that the impact on the gene-wide flux distribution and metabolism is moderate in the analysed time span. Rather, the photocatalytic action triggers the decreased expression of a large array of genes/proteins specific for regulatory, signalling and growth functions in parallel with subsequent selective effects on ion homeostasis, coenzyme-independent respiration and cell wall structure. The present work provides the first solid foundation for the biocidal action of titania and may have an impact on the design of highly active photobiocidal nanomaterials.

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

“…The total of 31 chemicals was quantified in cell cultures grown on either acetate or pyruvate (Supplementary Table S8). Metabolites were extracted as previously described (Kubacka et al, 2014) and analyzed on three complementary platforms including mass spectrometry (MS) with gas and liquid chromatography (LC) and capillary electrophoresis (CE) separations (gas chromatography-quadrupole time-of-flight (QTOF)-MS, LC-QTOF-MS and CE-TOF-MS). As indicated in Supplementary Table S8, these analytical platforms matched the nature of the chemical species.…”

Grafted semiconductors on PE-films leading to bacterial inactivation: Synthesis, characterization and mechanism

“…The mechanism of FeOx charge photo-generation will not be described in this study since it has been recently reported in our laboratory [16]. Also the TiO 2 -PE mediated bacterial inactivation has been reported widely in the open literature [1][2][3]18]. Below Eqs.…”

“…The intervention of FeOx injecting e − into TiO 2 is suggested in Eqs. (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13):…”

“…Bacterial inactivation materials/films have widely used TiO 2 and Fe-oxides under sunlight irradiation leading to highly oxidative radicals [1][2][3][4][5][6][7]. TiO 2 absorbs only 4-5% of the incident solar radiation with an absorption edge at ∼390 nm.…”

Impact of Iron Doping on Structural and Optical Properties of Titanium dioxide

“…TiO 2 has received great attention since the last two decades owing to its high refractive index, large dielectric constant, immense physio-chemical stability, colossal inertness in austere ambiences, reduced toxicity, low cost and hassle free developmental methods. Presently, TiO 2 is actively employed in optoelectronic sensors [1], waveguides [2], photovoltaic cells [3], photo catalysts [4], as pigments in paints [5] and food (for colouring and additives), biomaterials (as bone substituents and cardiovascular implants) [6] and neutralizing agent against microbial organisms [7]. TiO 2 , being a remarkable photocatalyst in UV region, lacks photophysical properties in visible region due to its large bandgap (3.25 eV).…”