Xiangyu Zhang,Guannan Zhang,Maozhou Chai,Xiaohong Yao,Weiyi Chen,Paul K. Chu
Treatment of implant-associated infection is becoming more challenging, especially when bacterial biofilms form on the surface of the implants. Developing multi-mechanism antibacterial methods to combat bacterial biofilm infections by the synergistic effects are superior to those based on single modality due to avoiding the adverse effects arising from the latter. In this work, TiO 2 nanorod arrays in combination with irradiation with 808 near-infrared (NIR) light are proven to eradicate single specie biofilms by combining photothermal therapy, photodynamic therapy, and physical killing of bacteria. The TiO 2 nanorod arrays possess efficient photothermal conversion ability and produce a small amount of reactive oxygen species (ROS). Physiologically, the combined actions of hyperthermia, ROS, and puncturing by nanorods give rise to excellent antibacterial properties on titanium requiring irradiation for only 15 min as demonstrated by our experiments conducted in vitro and in vivo . More importantly, bone biofilm infection is successfully treated efficiently by the synergistic antibacterial effects and at the same time, the TiO 2 nanorod arrays improve the new bone formation around implants. In this protocol, besides the biocompatible TiO 2 nanorod arrays, an extra photosensitizer is not needed and no other ions would be released. Our findings reveal a rapid bacteria-killing method based on the multiple synergetic antibacterial modalities with high biosafety that can be implemented in vivo and obviate the need for a second operation. The concept and antibacterial system described here have large clinical potential in orthopedic and dental applications.
Hydrogen peroxide (H 2 O 2 ) is a major transmitter of redox signals during chemical processes. Cost-effective and easy-to-operate sensors for H 2 O 2 are in high demand in a variety of fields. A novel photoelectrochemical (PEC) sensor for H 2 O 2 detection was investigated, using BiOBr/TiO 2 NAs/FTO (BiOBr/TNAs) as a PEC electrode which is obtained by successive ionic layer adsorption and reaction (SILAR) method. This non-enzymatic PEC BiOBr/TNAs electrode shows excellent selectivity, stability, and reproducibility for H 2 O 2 detection in optimizing modes. The linear relationship is in a broad range from 4 to 1800 μM (R 2 = 0.994) and a detection limit of 0.65 μM (S/N = 3). In the detection of H 2 O 2 in apple juice and milk real samples, the BiOBr/TNAs show outstanding recovery ranging from 98.0 % to 102.0 %, indicating great potential in practical applications. Meanwhile, the p-n heterojunction formed between BiOBr and TiO 2 improves the utilization of visible light and effectively promotes the separation of photogenerated electrons and holes. This work provides a new strategy for the non-enzymatic detection of hydrogen peroxide in PEC mode.
Firstly, Sb–SnO 2 /potassium titanate (Sb–SnO 2 /K 4 TiO 4 (KTO)) was fabricated by a sol-gel method, and then TiO 2 nanorod arrays were grown on the surface of Sb–SnO 2 /KTO by a hydrothermal method (TiO 2 NRA/Sb–SnO 2 /KTO). The photocatalytic activity was evaluated by degrading tetracycline hydrochloride (TCH). The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), ultraviolet–visible diffuse reflectance spectrometer (UV–Vis), and X-ray photoelectron spectroscopic characterizations (XPS). The results show that the Z-scheme heterojunction formed between SnO 2 /KTO and TiO 2 can enhance the range of light response. With the doping of Sb, the conductivity of the composite is enhanced, which is advantageous to the transfer of electron and the low recombination rate of electron-hole pairs. Thus, the doping of Sb is effective to improve the photocatalytic performance. Our work demonstrates the optimal doping amount of Sb is 5%. The degradation efficiency of TCH concentration can reach 95.6% after 2 h and TiO 2 NRA/Sb–SnO 2 /KTO shows good reusability .
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