AuPt Alloy Nanostructures with Tunable Composition and Enzyme-like Activities for Colorimetric Detection of Bisulfide

Weiwei He,Zhi Zheng,Yunlong Zhou,Junhui Cai,Xiangna Han,Huimin Jia

doi:10.1038/srep40103

Weiwei He, Zhi Zheng + Show 4 more

Open Access

https://doi.org/10.1038/srep40103

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Abstract

Tuning the enzyme-like activity and studying the interaction between biologically relevant species and nano-enzymes may facilitate the applications of nanostructures in mimicking natural enzymes. In this work, AuPt alloy nanoparticles (NPs) with varying compositions were prepared through a facile method by co-reduction of Au3+ and Pt2+ in aqueous solutions. The composition could be tuned easily by adjusting the molar ratios of added Pt2+ to Au3+. It was found that both peroxidase-like and oxidase-like activity of AuPt alloy NPs were highly dependent on the alloy compositions, which thus suggesting an effective way to tailor their catalytic properties. By investigating the inhibitory effects of HS− on the enzyme-like activity of AuPt alloy NPs and natural enzyme, we have developed a method for colorimetric detection of HS− and evaluation of the inhibiting effects of inhibitors on natural and artificial enzymes. In addition, the responsive ability of this method was influenced largely by the composition: AuPt alloy NPs show much lower limit of detection for HS− than Pt NPs while Pt NPs show wider linear range than AuPt alloy NPs. This study suggests the facile way not only for synthesis of alloy nanostructures, but also for tuning their catalytic activities and for use in bioanalysis.

Highlights

Metal NPs based enzyme mimetics have attracted particular attentions because of their defined mechanism, well-developed synthesis techniques, easy modification of surface and good bio-compatibility[19,20,21]
AuPt alloy NPs were prepared by the co-reduction of AuCl4− and PtCl42− with ascorbic acid in water
The High-resolution TEM (HRTEM) further indicates the dendritic structure of the Au0.5Pt0.5 alloy NPs and the well-defined lattice planes (Fig. 1b)

Summary

Introduction

Metal NPs based enzyme mimetics have attracted particular attentions because of their defined mechanism, well-developed synthesis techniques, easy modification of surface and good bio-compatibility[19,20,21]. In light of these findings and the unique properties of bimetallic NPs, a number of potential applications still remain to be explored that exploit the enzyme-mimicking functions of alloy NPs. For example, AuPt bimetallic nanostructures have exhibited intrinsic multiple enzyme-like activities, but most of these works involved AuPt bimetallic nanostructures rather than AuPt alloy nanoparticles[9,22,24,29,30,31]. The study on AuPt alloy nanoparticles for tailoring their chemical compositions to fine tune the oxidase and peroxidase-like activity and sensing capability for biodetection are limited. This knowledge will facilitate our understanding in depth the activity and applications of nanoenzymes. The alloy of Au with Pt shows a large effect on the linear range and limit of detection for HS−

Methods

Results

Conclusion