Chang Yun, Li Kai, Feng Yanlin, Cheng Yan, Zhang Mei, Wang Zuankai, Wu Zhijian, Zhang Haiyuan
a Laboratory of Chemical Biology , Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun , P.R. China.
b University of Chinese Academy of Sciences , Beijing , P.R. China.
Nanotoxicology. 2017 Sep;11(7):907-922. doi: 10.1080/17435390.2017.1382598. Epub 2017 Oct 5.
Developing catalytic and safe nanomaterials is very necessary for the reduction of potential risk to human health; however, this strategy has been found extremely challenging because the enhancement in catalytic activity of nanomaterials is inevitably accompanied with more potent cell injury. The relationship of physicochemical properties and biological responses in catalytic nanomaterials needs to be clarified at the nano-bio interface for achieving the safe application. Herein, high-energy crystallographic facets of palladium (Pd) nanocrystals that have been known to significantly contribute to the catalytic activity were introduced to attenuate the toxicity, and the underlying mechanism was unraveled. Polyhedral Pd nanocrystals with morphology evolution from truncated octahedron to cuboctahedron and cube were prepared for elaborately tuning the extents of high-energy {100} facets, and hierarchical in vitro and in vivo biological evaluation were performed to clarify that Pd nanocrystals exposed with the more {100} facets could show the less toxicity to cells and animals. Density functional theory (DFT) calculation revealed {100} facet exposure was endowed with a strong oxygen adsorption, which weakens the breakage of the water molecule and suppresses the hazardous water dissociation and hydroxyl radical generation, which was supported by electron spin resonance (ESR)-based radical evaluation and X-ray photoelectron spectroscopy (XPS)-based oxygen identification. This means high-energy facet-based catalytic Pd nanocrystals can deliver low toxicity due to their unique surface properties.
开发具有催化活性且安全的纳米材料对于降低对人类健康的潜在风险非常必要；然而，人们发现这一策略极具挑战性，因为纳米材料催化活性的增强不可避免地伴随着更强的细胞损伤。为实现安全应用，需要在纳米-生物界面阐明催化纳米材料的物理化学性质与生物反应之间的关系。在此，引入已知对催化活性有显著贡献的钯（Pd）纳米晶体的高能晶体面以降低毒性，并揭示其潜在机制。制备了从截角八面体到立方八面体再到立方体形态演变的多面体Pd纳米晶体，以精细调节高能{100}面的程度，并进行了分层的体外和体内生物学评估，以阐明暴露有更多{100}面的Pd纳米晶体对细胞和动物的毒性较小。密度泛函理论（DFT）计算表明，{100}面暴露具有很强的氧吸附能力，这减弱了水分子的分解，抑制了有害的水离解和羟基自由基的产生，基于电子自旋共振（ESR）的自由基评估和基于X射线光电子能谱（XPS）的氧识别也证实了这一点。这意味着基于高能面的催化Pd纳米晶体因其独特的表面性质可以具有低毒性。
