Novel porous Cr-doped SrTiO3 nanotubes were fabricated using a simple and economical electrospinning technique with subsequent calcination. The average outer diameter of the nanotube was approximately 100 nm, and the multimodal porous netlike framework with high specific surface area was favorable for light harvesting and matter diffusion. Photocatalytic activity was evaluated by degradation of azo dye acid orange 7 and removal of NO under visible light irradiation. The enhanced photocatalytic activity of porous Cr-doped SrTiO3 nanotubes was attributed to the one-dimensional tube-like architecture, high specific surface area, multimodal pore size distribution, and proper Cr doping.
Yang Dong,Zou Xiaoyan,Tong Zhenwei,Nan Yanhu,Ding Fei,Jiang Zhongyi
One-dimensional nanotubes have attracted enormous attention due to their specific structure and excellent performance since the carbon nanotube was prepared. In this study, the open-ended SrTiO 3 nanotubes (STNTs) have been fabricated for the first time via an isomorphic conversion strategy using the protonated titanate nanotubes (HTNTs) as the precursor and template under the hydrothermal treatment. The as-prepared STNTs consist of uniform and continuous multilayers, having inner and outer diameters about 8.0 and 13 nm. The STNT formation involves the exchange of Sr 2+ ions with H + ions in HTNTs and then in situ growth of cubic SrTiO 3 crystals by the templating of HTNT frameworks. It is found that the diffusion process of Sr 2+ ions plays a critical role in controlling the nanotube morphology of SrTiO 3 crystals. In addition, the SrTiO 3 nanotubes exhibit high photocatalytic activity for the Cr(VI) reduction, which can reduce nearly 100% Cr(VI) within 6 h under simulated sunlight irradiation. The current strategy may be broadly applicable for fabricating the nanotubes from raw materials without 2D layered nanostructure.
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Kun Wang,Mingze Gao,Juncheng Fan,Jingjing Huo,Pengxiang Liu,Rui Ding,Peng Li
Infection and aseptic loosening caused by bacteria and poor osseointegration remain serious challenges for orthopedic implants. The advanced surface modification of implants is an effective strategy for addressing these challenges. This study presents a “pneumatic nanocannon” coating for titanium orthopedic implants to achieve on-demand release of antibacterial and sustained release of osteogenic agents. SrTiO3 nanotubes (SrNT) were constructed on the surface of Ti implants as “cannon barrel,” the “cannonball” (antibiotic) and “propellant” (NH4HCO3) were codeposited into SrNT with assistance of mussel-inspired copolymerization of dopamine and subsequently sealed by a layer of polydopamine. The encapsulated NH4HCO3 within the nanotubes could be thermally decomposed into gases under near-infrared irradiation, propelling the on-demand delivery of antibiotics. This coating demonstrated significant efficacy in eliminating typical pathogenic bacteria both in planktonic and biofilm forms. Additionally, this coating exhibited a continuous release of strontium ions, which significantly enhanced the osteogenic differentiation of preosteoblasts. In an implant-associated infection rat model, this coating demonstrated substantial antibacterial efficiency (>99%) and significant promotion of osseointegration, along with alleviated postoperative inflammation. This pneumatic nanocannon coating presents a promising approach to achieving on-demand infection inhibition and sustained osseointegration enhancement for titanium orthopedic implants.
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