Facile Synthesis of Pd-Ir Nanocubes for Biosensing.

Jiuxing Li,Yingfu Li

doi:10.3389/fchem.2021.775220

Abstract

Displaying extremely high peroxidase-like activity and uniform cubic structure enclosed by (100) facets, Pd-Ir nanocubes are an attractive nanomaterial for bioanalysis. However, there exists a great challenge to deposit atomic layers of Ir on the surface of Pd nanocubes due to the relatively low energy barrier of homogeneous nucleation of Ir atoms compared to heterogeneous nucleation. Here, a simple and surfactant-free approach is presented to synthesize Pd-Ir nanocubes with atomic Ir shell thickness in an aqueous solution at room temperature. Biomolecules such as antibodies and nucleic acids have free access to the surface of Pd-Ir nanocubes. Applications of Pd-Ir nanocubes in immunoassays and aptamer-based biosensors are realized, exploiting the excellent peroxidase activity and fluorescence quenching ability of Pd-Ir nanocubes. This work makes a significant step forward towards the practical utility of Pd-Ir nanocubes in bioanalysis.

Highlights

In recent years, nanomaterials have attracted increasing research interests in bioanalysis due to their outstanding optical, electronic, and catalytic properties (Link and El-Sayed, 1999; Burda et al, 2005; Willets and Van Duyne, 2007; Anker et al, 2008; Saha et al, 2012; Wei and Wang, 2013; Lin et al, 2014; Wu et al, 2019)
Pd nanocubes catalyze the hydrolysis of NaBH4 to form hydrogen-capped Pd nanocubes, which reduce IrCl63- to form Pd-Ir nanocubes
Due to surfactant-free synthesis, Pd-Ir nanocubes can be conjugated with antibodies by physical adsorption, avoiding the timeconsuming and complex process of chemical conjugation (Xia et al, 2015)

Summary

Introduction

Nanomaterials have attracted increasing research interests in bioanalysis due to their outstanding optical, electronic, and catalytic properties (Link and El-Sayed, 1999; Burda et al, 2005; Willets and Van Duyne, 2007; Anker et al, 2008; Saha et al, 2012; Wei and Wang, 2013; Lin et al, 2014; Wu et al, 2019). We describe a simple and surfactant-free method for depositing atomic Ir shells on Pd nanocubes in an aqueous solution at room temperature. The nanomaterials are further exploited for the development of an immunoassay to detect PSA (prostate-specific antigen) as well as fluorescent and colorimetric biosensors of C. difficile RNase HII.

Results

Conclusion