Su Wendi, Wang Hao, Pan Juhong, Pu Huan, Gui Bin, Liu Qianhui, Cao Sheng, Zhou Qing
Department of Ultrasound Imaging, Renmin Hospital of Wuhan University, Wuhan, China.
Department of Ultrasound Imaging, Renmin Hospital of Wuhan University, Wuhan, China.
Ultrasound Med Biol. 2025 Jul 19. doi: 10.1016/j.ultrasmedbio.2025.05.010.
Cerium oxide nanoparticles (CeO NPs), as metal oxide nanomaterials with multi-enzyme activities, are gradually being applied in the biomedical field. However, we have limited knowledge about the factors influencing the enzymatic activity and biological functions of cerium oxide nanoparticles. This study aims to investigate whether ultrasonic irradiation has a significant impact on their enzymatic activity, reactive oxygen species scavenging ability, and antibacterial activity, and to discuss the underlying mechanisms of these effects.
We first synthesized cerium oxide nanoparticles using a chemical precipitation method and characterized them. We set up a control group and irradiation groups with different ultrasonic parameters, and tested the mimicking activities of catalase, superoxide dismutase, and peroxidase of the cerium oxide nanoparticles using enzymatic activity assay kits. Then, we assessed the biocompatibility of the cerium oxide nanoparticles in macrophages. Subsequently, we examined their reactive oxygen species scavenging ability in both tumor cells and macrophages. Finally, we tested their inhibitory effect on Staphylococcus aureus.
We found that cerium oxide nanoparticles exhibited enhanced enzymatic activity after ultrasound irradiation. The direction of their catalysis was regulated by pH: in environments with lower pH values, the peroxidase activity of the cerium oxide nanoparticles was stronger than that of catalase and superoxide dismutase, whereas in environments with higher pH values, the opposite was true. This pH-regulated multienzymatic activity resulted in significantly different reactive oxygen species (ROS) scavenging abilities between acidic tumor cells and slightly alkaline normal tissue cells: it demonstrated excellent ROS scavenging ability in macrophages but showed no ROS scavenging ability in tumor cells. Lastly, we discovered that the nanoparticles exhibited stronger antibacterial capabilities after ultrasound irradiation.
Ultrasound can enhance the enzymatic activity, ROS scavenging ability, and antibacterial capability of cerium oxide nanoparticles.
氧化铈纳米颗粒（CeO NPs）作为具有多种酶活性的金属氧化物纳米材料，正逐渐应用于生物医学领域。然而，我们对影响氧化铈纳米颗粒酶活性和生物学功能的因素了解有限。本研究旨在探讨超声辐照是否对其酶活性、活性氧清除能力和抗菌活性有显著影响，并探讨这些影响的潜在机制。
我们首先采用化学沉淀法合成氧化铈纳米颗粒并对其进行表征。我们设置了对照组和具有不同超声参数的辐照组，使用酶活性检测试剂盒测试氧化铈纳米颗粒的过氧化氢酶、超氧化物歧化酶和过氧化物酶的模拟活性。然后，我们评估了氧化铈纳米颗粒在巨噬细胞中的生物相容性。随后，我们检测了它们在肿瘤细胞和巨噬细胞中的活性氧清除能力。最后，我们测试了它们对金黄色葡萄球菌的抑制作用。
我们发现超声辐照后氧化铈纳米颗粒的酶活性增强。其催化方向受pH调节：在较低pH值的环境中，氧化铈纳米颗粒的过氧化物酶活性强于过氧化氢酶和超氧化物歧化酶，而在较高pH值的环境中则相反。这种pH调节的多酶活性导致酸性肿瘤细胞和微碱性正常组织细胞之间的活性氧（ROS）清除能力存在显著差异：它在巨噬细胞中表现出优异的ROS清除能力，但在肿瘤细胞中没有表现出ROS清除能力。最后，我们发现纳米颗粒在超声辐照后表现出更强的抗菌能力。
超声可增强氧化铈纳米颗粒的酶活性、ROS清除能力和抗菌能力。
