Visible-Light-Responsive Antibacterial Property of Boron-Doped Titania Films

Abstract

Pure titanium dioxide TiO2 photocatalytic substrates exhibit antibacterial activity only when they are irradiated with ultraviolet light, which comprises high-energy wavelengths that damage all life. Impurity doping of TiO2-related materials enables visible light to stimulate photocatalytic activity, which enhances opportunities for TiO2 to be used as a disinfectant in living environments. Boron-doped TiO2 displays visible-light-responsive bactericidal properties. However, because boron-derived compounds also exert notable antibacterial effects, most reports did not clearly demonstrate the extent to which the bactericidal property of boron-doped TiO2 is contributed by visible-light-stimulated photocatalysis. In addition, TiO2 thin films have considerable potential for applications in equipment that requires sterilization; however, the antibacterial properties of boron-doped TiO2 thin films have been examined by only a few studies. We found that boron-doped TiO2 thin films displayed visible-light-driven antibacterial properties. Moreover, because boron compounds may have intrinsic antibacterial properties, using control groups maintained in the dark, we clearly demonstrated that visible light stimulated the photocatalysis of boron-doped TiO2 thin films but not the residue boron compounds display antibacterial property. The bactericidal effects induced by visible light are equally potent for the elimination of the model organism Escherichia coli and human pathogens, such as Acinetobacter baumannii, Staphylococcus aureus, and Streptococcus pyogenes. The antibacterial applications of boron-doped TiO2 thin films are described, and relevant perspectives discussed.

Dengue Virus Envelope Protein Domain III Induces Nlrp3 Inflammasome-Dependent NETosis-Mediated Inflammation in Mice

“…Mosquito C6/36 cell line (ATCC CRL-1660) and DENV-2 (PL046) were maintained and amplified using standard cell culture methods ( 36 – 38 ). Soluble recombinant proteins glutathione-S transferase (rGST), and EIII (rEIII) were obtained from cultured bacteria ( Escherichia coli ) ( 39 ), after isopropyl β-D-1-thiogalactopyranoside induction, and were purified as previously described ( 32 , 33 , 36 ). To reduce endotoxin (lipopolysaccharide; LPS) contamination to a desired level (<1 EU/mg protein), the lysate- and resin-packed column was washed with a buffer (8 M urea, 100 mM NaH 2 PO 4 , and 10 mM Tris-HCl; pH = 6.3) with the addition of 1% Triton X-114 (Sigma–Aldrich, St. Louis, MO, USA).…”

Opportunistic gill infection is associated with TiO2 nanoparticle-induced mortality in zebrafish

“…Adult wild zebrafish were used in the experiment and were kept in a semistatic system with charcoal-filtered tap water (pH 7.0-7.4) at 28 ± 0.5˚C as recommended in a previous study PLOS ONE [38], with a 12-h light-12-h dark (12L:12D) photocycle (Classictone incandescent lamp, Philips; Taiwan, without illuminating UV to avoid UV-induced photocatalysis [5,11,12,33,39,40]). The fish were fed newly hatched brine shrimp and pellet food (Zeigler Brothers, Gardners, PA, USA) and were kept in 30-L glass tanks with 20 L of water per tank.…”

“…The gill and fin tissue samples were excised, weighed, cut into small pieces, and homogenized with 100 μL of phosphate-buffered saline at 4˚C. Next, the 30-μL tissue homogenates were placed on luria broth (LB) agar plates (BD Difco LB Agar; Becton Dickinson, Taipei, Taiwan), using standard bacterial culture protocols [39,47]. The bacteria colony-forming unit on the plates was determined at a 24-h incubation period at 37˚C according to previously described methods [39].…”

“…Next, the 30-μL tissue homogenates were placed on luria broth (LB) agar plates (BD Difco LB Agar; Becton Dickinson, Taipei, Taiwan), using standard bacterial culture protocols [39,47]. The bacteria colony-forming unit on the plates was determined at a 24-h incubation period at 37˚C according to previously described methods [39]. The zebrafish (AB strain) used in the present study were obtained from the zebrafish facility at the Laboratory Animal center of Tzu Chi University.…”

The Cerium/Boron Insertion Impact in Anatase Nano-Structures on the Photo-Electrochemical and Photocatalytic Response

“…Thus, cerium-based oxides compounds have received a lot of attention because of the redox couple Ce 4+ /Ce 3+ has the ability to exchange, during bias potential, CeO2 and Ce2O3 chemical states [20][21][22][23][24]. The easy formation of available oxygen vacancies (OV) in the presence of boron species with a relative high mobility of oxygen species in the bulk has been reported [13,[25][26][27][28][29].…”