RESUMEN

Catalytic nanomaterials can be used extrinsically to combat diseases associated with a surplus of reactive oxygen species (ROS). Rational design of surface morphologies and appropriate doping can substantially improve the catalytic performances. In this work, a class of hollow polyvinyl pyrrolidone-protected PtPdRh nanocubes with enhanced catalytic activities for in vivo free radical scavenging is proposed. Compared with Pt and PtPd counterparts, ternary PtPdRh nanocubes show remarkable catalytic properties of decomposing H2 O2 via enhanced oxygen reduction reactions. Density functional theory calculation indicates that the bond of superoxide anions breaks for the energetically favorable status of oxygen atoms on the surface of PtPdRh. Viability of cells and survival rate of animal models under exposure of high-energy γ radiation are considerably enhanced by 94% and 50% respectively after treatment of PtPdRh nanocubes. The mechanistic investigations on superoxide dismutase (SOD) activity, malondialdehyde amount, and DNA damage repair demonstrate that hollow PtPdRh nanocubes act as catalase, peroxidase, and SOD analogs to efficiently scavenge ROS.

Asunto(s)

Nanoestructuras/química , Paladio/química , Platino (Metal)/química , Especies Reactivas de Oxígeno/metabolismo , Catalasa/metabolismo , Catálisis , Peróxido de Hidrógeno/química , Peróxido de Hidrógeno/metabolismo , Peroxidasa/metabolismo , Superóxido Dismutasa/metabolismo

RESUMEN

Ionizing radiation produces excessive reactive oxygen species (ROS) which impose detrimental effects on biological systems. Thus, it is important to explore clinically safe and efficacious radioprotection agents to scavenge ROS and reduce the risks of radiotherapy. Recently, emerging catalytic nanomaterials such as sulfide nanomaterials have shown capability of clearing ROS in vivo by unique electron transfers between atoms, but their catalytic activities are yet suboptimal. As such, there is an unmet need to improve catalytic properties for stronger antioxidant activities and radiation protection. Herein, we prepared ultrasmall Au-MoS2 clusters (∼2.5 nm) and they showed enhanced catalytic properties via gold intercalation facilitating increased active sites and synergistic effects. Electrocatalysis results revealed that the catalytic activity of Au-MoS2 towards H2O2 was superior to ultrasmall MoS2 without Au. As a result, we found that improving the electrocatalytic property of Au-MoS2 can effectively enhance corresponding antioxidant activities and radioprotection effects in vivo. In addition, Au-MoS2 also showed significant radioprotection in vitro and dramatically reduced the excess of radiation-induced adverse ROS. It also rescued radiation-induced DNA damages and protected the bone marrow hematopoietic system from ionizing radiation.

RESUMEN

High energy ionizing radiation was widely used in medical diagnosis and cancer radiation therapy. The high dose of X ray or γ ray can cause the damage of cancerous tissue as well as healthy tissue during therapy. Therefore, it is urgent to develop chemical agents to protect the healthy tissue from high energy ray invasion. Here, the ultrasmall Pt clusters were employed as the anti-radiation agents for protecting healthy cells and improving survival rate of irradiated mice. It was found that Pt clusters can reduce the DNA damages in irradiated cells. In vivo experiments show that the Pt clusters treatment can improve the survival rate of irradiated mice up to 30%. As a contrast, only-irradiated mice without Pt clusters treatment completely died after 15 days. The detailed biological experiments showed that Pt clusters can recover the bone marrow DNA level and superoxide dismutase activities via scavenging free radicals. Importantly, the ultrasmall Pt clusters can be excreted rapidly by kidney and do not cause long-term toxicity.