Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Nanoscale. 2016 Jul 14;8(28):13562-7. doi: 10.1039/c6nr02730j.
Nanomaterial-based enzyme mimics (nanozymes) are currently a new forefront of chemical research. However, the application of nanozymes is limited by their low catalytic activity and low turnover numbers. Cerium dioxide nanoparticles (nanoceria) are among the few with oxidase activity. Herein, we report an interesting finding addressing their limitations. The oxidase activity of nanoceria is improved by over 100-fold by fluoride capping, making it more close to real oxidases. The turnover number reached 700 in 15 min, drastically improved from ∼15 turnovers for the naked particles. The mechanism is attributed to surface charge modulation and facilitated electron transfer by F(-) capping based on ζ-potential and free radical measurements. Ultrasensitive sensing of fluoride was achieved with a detection limit of 0.64 μM F(-) in water and in toothpastes, while no other tested anions can achieve the activity enhancement.
基于纳米材料的酶模拟物（纳米酶）是目前化学研究的一个新前沿。然而，纳米酶的应用受到其低催化活性和低周转率的限制。二氧化铈纳米颗粒（纳米氧化铈）是少数具有氧化酶活性的纳米酶之一。在此，我们报告了一个有趣的发现，解决了它们的局限性。氟化物封端使纳米氧化铈的氧化酶活性提高了 100 多倍，使其更接近真正的氧化酶。在 15 分钟内达到了 700 的周转率，与裸颗粒的约 15 个周转率相比有了显著提高。该机制归因于表面电荷调制和 F(-)封端促进电子转移，这是基于 ζ 电位和自由基测量得出的。在水中和牙膏中，氟化物的超灵敏检测限达到了 0.64 μM F(-)，而没有其他测试的阴离子可以实现这种活性增强。
