Platinum-Nickel Nanoparticles with Enhanced Oxidase-like Activity for Total Antioxidant Capacity Bioassay

While great progress in nanozyme-enabled analytical chemistry has been made, most current nanozyme-based biosensing platforms are based on peroxidase-like nanozymes. However, peroxidase-like nanozymes with multienzymatic activities can influence the detection sensitivity and accuracy, while the use of unstable hydrogen peroxide (H2O2) in a peroxidase-like catalytic reaction may result in the reproducibility challenge of sensing signals. We envision that constructing biosensing systems by using oxidase-like nanozymes can address these limitations. Herein, we reported that platinum-nickel nanoparticles (Pt-Ni NPs) with Pt-rich shells and Ni-rich cores possessed high oxidase-like catalytic efficiency, exhibiting a 2.18-fold higher maximal reaction velocity (v(max)) than initial pure Pt NPs. The oxidase-like Pt-Ni NPs were applied to develop a colorimetric assay for the determination of total antioxidant capacity (TAC). The antioxidant levels of four bioactive small molecules, two antioxidant nanomaterials, and three cells were successfully measured. Our work not only provides new insights for preparing highly active oxidase-like nanozymes but also manifests their applications for TAC analysis.

Automated summary

While most nanozyme-based biosensing platforms currently rely on peroxidase-like nanozymes, this study demonstrates the potential of using oxidase-like nanozymes for biosensing applications. The use of platinum-nickel nanoparticles with oxidase-like catalytic efficiency resulted in improved detection sensitivity and accuracy compared to pure platinum nanoparticles. These oxidase-like nanzymes were successfully applied for the determination of total antioxidant capacity in various samples. The study not only contributes to the development of highly active oxidase-like nanozymes but also showcases their potential for TAC analysis.