Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
NanoScience Technology Center, University of Central Florida, Orlando, FL 32816, USA.
Chembiochem. 2020 Sep 1;21(17):2440-2444. doi: 10.1002/cbic.202000147. Epub 2020 May 8.
Comprehensive studies on the size effect in nanozyme (i. e., nanomaterials with enzyme-like activities)-based catalysis have rarely been reported. In this work, we systematically investigated the size effect in nanozymes by using Pd-Ir core-shell nanoparticles with peroxidase-like activities as a model system. Pd-Ir nanoparticles with four different sizes (3.3, 5.9, 9.8 and 13.0 nm), but identical shapes and surface structures, were designed and synthesized. We found that the catalytic activity for individual nanozymes increased with particle size. The area-specific catalytic activity was similar for nanoparticles of 3.3-9.8 nm, but decreased slightly when particle size reached 13.0 nm. By using an enzyme-linked immunosorbent assay (ELISA) as a model platform, the size effect of Pd-Ir nanoparticles in biosensing applications was investigated; smaller nanoparticles were found to offer lower detection limits. This work not only demonstrates the size effect, but also provides an effective strategy to enhance the performance of nanozymes in certain applications.
关于纳米酶（即具有类似酶活性的纳米材料）催化中的尺寸效应的综合研究很少有报道。在这项工作中，我们以具有过氧化物酶样活性的 Pd-Ir 核壳纳米粒子为模型体系，系统地研究了纳米酶中的尺寸效应。设计并合成了具有四种不同尺寸（3.3、5.9、9.8 和 13.0nm）但形状和表面结构相同的 Pd-Ir 纳米粒子。我们发现，单个纳米酶的催化活性随粒径的增加而增加。粒径为 3.3-9.8nm 的纳米粒子的比表面积催化活性相似，但当粒径达到 13.0nm 时略有下降。通过将酶联免疫吸附测定（ELISA）用作模型平台，研究了 Pd-Ir 纳米粒子在生物传感应用中的尺寸效应；较小的纳米粒子具有更低的检测限。这项工作不仅证明了尺寸效应，而且为在某些应用中增强纳米酶的性能提供了一种有效策略。
