Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, 119991 Moscow, Russia.
Department of Physical and Colloid Chemistry, Faculty of Chemical and Environmental Engineering, National University of Oil and Gas "Gubkin University", 119991 Moscow, Russia.
Molecules. 2023 Apr 29;28(9):3811. doi: 10.3390/molecules28093811.
The enzyme-like activity of metal oxide nanoparticles is governed by a number of factors, including their size, shape, surface chemistry and substrate affinity. For CeO nanoparticles, one of the most prominent inorganic nanozymes that have diverse enzymatic activities, the size effect remains poorly understood. The low-temperature hydrothermal treatment of ceric ammonium nitrate aqueous solutions made it possible to obtain CeO aqueous sols with different particle sizes (2.5, 2.8, 3.9 and 5.1 nm). The peroxidase-like activity of ceria nanoparticles was assessed using the chemiluminescent method in different biologically relevant buffer solutions with an identical pH value (phosphate buffer and Tris-HCl buffer, pH of 7.4). In the phosphate buffer, doubling CeO nanoparticles' size resulted in a two-fold increase in their peroxidase-like activity. The opposite effect was observed for the enzymatic activity of CeO nanoparticles in the phosphate-free Tris-HCl buffer. The possible reasons for the differences in CeO enzyme-like activity are discussed.
金属氧化物纳米粒子的酶样活性受多种因素的影响，包括其尺寸、形状、表面化学和底物亲和力。对于 CeO 纳米粒子，作为具有多种酶活性的最突出的无机纳米酶之一，其尺寸效应仍未得到很好的理解。采用低温水热法处理硝酸铈铵的水溶液，可以得到不同粒径（2.5、2.8、3.9 和 5.1nm）的 CeO 水溶胶。采用化学发光法在不同具有相同 pH 值（磷酸缓冲液和 Tris-HCl 缓冲液，pH 值为 7.4）的生物相关缓冲液中评估了 CeO 纳米粒子的过氧化物酶样活性。在磷酸缓冲液中，CeO 纳米粒子的尺寸增加一倍导致其过氧化物酶样活性增加一倍。在无磷酸的 Tris-HCl 缓冲液中，CeO 纳米粒子的酶活性则出现相反的效果。讨论了 CeO 类酶活性差异的可能原因。
