Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, Guangdong, 510006, China.
Nanoscale. 2023 Mar 30;15(13):6295-6305. doi: 10.1039/d2nr07148g.
Palladium (Pd) nanocrystals with different crystalline forms exhibit distinct enzyme-like activities in generating reactive oxygen species (ROS). How such crystallinity-dependent catalytic activity regulates potential cytotoxicity remains to be elucidated. In the present work, Pd nanocrystals with four different crystalline forms were synthesized, and the underlying mechanisms involved in ROS-mediated cytotoxicity were systematically revealed. Pd nanocrystals with the {100} (nanocubes) and {111} (nanooctahedrons and nanotetrahedrons) facets triggered cytotoxicity by generating singlet oxygen (O) and hydroxyl radicals (OH˙), respectively. Meanwhile, Pd nanoconcave-tetrahedrons, which had both the {110} and {111} facets, induced ROS-mediated cytotoxicity activating the superoxide (O˙) pathway. Consumption of protons and generation of hydroxide during intracellular ROS conversion resulted in pH alkalization, eventually leading to cell death. Our findings emphasize the importance of facet-dependent ROS generation promoted by Pd nanocrystals. Furthermore, alkalization is identified as a new biomarker for analyzing ROS-mediated cytotoxicity.
钯（Pd）纳米晶体具有不同的晶体形态，在产生活性氧物种（ROS）方面表现出明显的酶样活性。然而，这种晶态依赖性催化活性如何调节潜在的细胞毒性仍有待阐明。在本工作中，我们合成了具有四种不同晶体形态的 Pd 纳米晶体，并系统地揭示了 ROS 介导的细胞毒性的潜在机制。具有{100}（纳米立方体）和{111}（纳米八面体和纳米四面体）晶面的 Pd 纳米晶体通过生成单线态氧（O）和羟基自由基（OH˙）分别引发细胞毒性。同时，具有{110}和{111}晶面的 Pd 凹四面体通过激活超氧阴离子（O˙）途径诱导 ROS 介导的细胞毒性。细胞内 ROS 转化过程中质子的消耗和氢氧根的生成导致 pH 值碱化，最终导致细胞死亡。我们的研究结果强调了 Pd 纳米晶体促进的依赖于晶面的 ROS 生成的重要性。此外，碱化被确定为分析 ROS 介导的细胞毒性的一个新的生物标志物。
