期刊
ACS APPLIED MATERIALS & INTERFACES
卷 7, 期 15, 页码 8233-8242出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.5b01271
关键词
iridium nanoparticles; polyvinylpyrrolidone; catalase- and peroxidase-like activity; catalytic mechanism; H2O2-induced cytotoxicity reduction; antioxidants
资金
- National Natural Science Foundation of China [21231007]
- 973 Program [2014CB845604]
- Ministry of Education of China [IRT1298, 313058]
- Guangdong Provincial Government
- Fundamental Research Funds for the Central Universities
Polyvinylpyrrolidone-stabilized iridium nano-particles (PVP-IrNPs), synthesized by the facile alcoholic reduction method using abundantly available PVP aS protecting agents, were first reported as enzyme mimics showing intrinsic catalase- and peroxidase-like activities. The preparation procedure was much easier and more importantly, kinetic studies found that the catalytic activity of PVP-IrNPs was comparable to previously reported platinum nanoparticles. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterization indicated that PVP-IrNPs had the average size of approximately 1.5 nm and mainly consisted of Ir(0) chemical state. The mechanism of PVP-IrNPs' dual-enzyme activities was investigated using XPS, Electron spin resonance (ESR) and cytochrome C-based electron transfer methods. The catalase-like activity was related to the formation of oxidized species Ir(0)@IrO2 upon reaction with H2O2. The peroxidase-like activity originated from their ability acting as electron transfer mediators during the catalysis cycle, without the production of hydroxyl radicals. Interestingly, the protective effect of PVP-IrNPs against H2O2-induced cellular oxidative damage was investigated in an A549 lung cancer cell model and PVP-IrNPs displayed excellent biocompatibility and antioxidant activity. Upon pretreatment of cells with PVP-IrNPs, the intracellular reactive oxygen species (ROS) level in response to H2O2 was decreased and the cell viability increased. This work will facilitate studies on the mechanism and biomedical application of nanomaterials-based enzyme mimic.
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