Metal oxides are receiving an incremental attention in recent years for their potential applications in ablation of cancer cells due to their efficient photothermal conversion and good biocompatibility, but the large sizes and poor photo-stability will seriously limit their practical application. Herein, hydrous RuO2 nanoparticles were synthesized by a facile hydrothermal treatment and surface-modified with polyvinylpyrrolidone (PVP) coating. PVP-coated RuO2 nanoparticles exhibit a well dispertion in saline solution, strong characteristic plasmonic absorption in NIR region, enhanced photothermal conversion efficiency of 54.8% and remarkable photo-stability under the irridation of an 808 nm laser. The nanoparticles were further employed as a new photothermal ablation agent for cancer cells which led rapidly to cellular deaths both in vitro and in vivo.
Developing low-cost catalysts with high activity for the Hydrogen Evolution Reaction (HER) is a main challenge to reduce the dependence on precious metals while maintaining the catalytic activity. In this study, nickel-plated multi-walled carbon nanotubes (Ni-MWCNTs) with a large number of active sites were selected, and Ni-MWCNTs electrocatalysts loaded with trace amounts of RuO 2 nanoparticles were prepared by annealing treatment, which exhibited excellent HER performances in both acidic and alkaline media. The RuO 2 nanoparticles loaded nickel-coated multi-walled carbon nanotubes (RuO 2 @Ni-MWCNTs) had a small electrochemical impedance spectrum (EIS) and a large electrochemically active surface area (ECSA). Notably, RuO 2 @Ni-MWCNTs with less than 1 % Ru content exhibited excellent catalytic activities in both acidic and alkaline solutions. The results showed that the overpotentials of RuO 2 @Ni-MWCNTs were 20.2 mV (alkaline) and 73.7 mV (acidic), respectively. After stabilization at 20 mA cm −2 for 90 h, the evaluation results showed that RuO 2 @Ni-MWCNTs could maintain their catalytic efficiency without significant degradation.
Zhou Liu,Lina Xie,Kangqiang Qiu,Xinxing Liao,Thomas W. Rees,Zizhuo Zhao,Liangnian Ji,Hui Chao
Oxidative stress induced by reactive oxygen species (ROS) is one of the major pathological mechanisms of acute kidney injury (AKI). Inorganic nanomaterial-mediated antioxidant therapy is considered a promising method for the prevention of AKI; however, currently available antioxidants for AKI exhibit limited clinical efficacy due to the glomerular filtration threshold (∼6 nm). To address this issue, we developed ultrasmall RuO2 nanoparticles (RuO2NPs) (average size ≈ 2 nm). The NPs show excellent antioxidant activity and low biological toxicity. In addition, they can pass through the glomerulus to be excreted. These properties in combination make the ultrasmall RuO2NPs promising as a nanozyme for the prevention of AKI. The NP catalytic properties mimic the activity of catalase, peroxidase, superoxide dismutase, and glutathione peroxidase. The nanozyme can be efficiently and rapidly absorbed by human embryonic kidney cells while significantly reducing ROS-induced apoptosis by eliminating excess ROS. After intravenous injection, the ultrasmall RuO2NPs significantly inhibit the development of AKI in mice. In vivo toxicity experiments demonstrate the biosafety of the NPs after long-term preventing. The multienzyme-like activity and biocompatibility of the ultrasmall RuO2NPs makes them of great interest for applications in the fields of biomedicine and biocatalysis.
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