A Competitive Assay Based on Dual-Mode Au@Pt-DNA Biosensors for On-Site Sensitive Determination of Carbendazim Fungicide in Agricultural Products

Ge Chen,Xiaodong Huang,Maojun Jin,Donghui Xu,Guangyang Liu,Rongqi Zhai,A M Abd El-Aty,Jing Wang,Lingyun Li,Xiaomin Xu,Yanguo Zhang,Kaige Zhang

doi:10.3389/fnut.2022.820150

Abstract

Carbendazim (CBZ), a systemic, broad-spectrum benzimidazole fungicide, is widely used to control fungal diseases in agricultural products. Its residues might pose risks to human health and the environment. Therefore, it is warranted to establish a rapid and reliable method for its residual quantification. Herein, we proposed a competitive assay that combined aptamer (DNA) specific recognition and bimetallic nanozyme gold@platinum (Au@Pt) catalysis to trace the CBZ residue. The DNA was labeled onto bimetallic nanozyme Au@Pt surface to produce Au@Pt probes (Au@Pt-DNA). The magnetic Fe3O4 was functionalized with a complementary strand of DNA (C-DNA) to form Fe3O4 probes (Fe3O4-C-DNA). Subsequently, the CBZ and the Fe3O4 probes competitively react with Au@Pt probes to form two Au@Pt-DNA biosensors (Au@Pt-ssDNA-CBZ and Au@Pt-dsDNA-Fe3O4). The Au@Pt-ssDNA-CBZ biosensor was designed for qualitative analysis through a naked-eye visualization strategy in the presence of CBZ. Meanwhile, Au@Pt-dsDNA-Fe3O4 biosensor was developed to quantitatively analyze CBZ using a multifunctional microplate reader. A competitive assay based on the dual-mode Au@Pt-DNA biosensors was established for onsite sensitive determination of CBZ. The limit of detection (LOD) and recoveries of the developed assay were 0.038 ng/mg and 71.88-110.11%, with relative standard deviations (RSDs) ranging between 3.15 and 10.91%. The assay demonstrated a good correlation with data acquired from liquid chromatography coupled with mass spectrometry/mass spectrometry analysis. In summary, the proposed competitive assay based on dual-mode Au@Pt-DNA biosensors might have a great potential for onsite sensitive detection of pesticides in agro-products.

Highlights

Carbendazim (CBZ) is a broad-spectrum benzimidazole fungicide used to protect a wide variety of crops against fungal disease, producing high-quality crops with optimal yields [1, 2]
A variety of classical quantitive analyses, including liquid chromatography coupled with mass spectrometry (LC-MS) [4] and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) [5], have been routinely used to monitor CBZ residues in the agricultural products
The morphology of Au@Pt nanoparticles was characterized by transmission electron microscopy (TEM)

Summary

Introduction

Carbendazim (CBZ) is a broad-spectrum benzimidazole fungicide used to protect a wide variety of crops against fungal disease, producing high-quality crops with optimal yields [1, 2]. A variety of classical quantitive analyses, including liquid chromatography coupled with mass spectrometry (LC-MS) [4] and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) [5], have been routinely used to monitor CBZ residues in the agricultural products. These analytical methods provide high stability and accuracy, preparation steps are laborious, timeconsuming, requiring professional operators and expensive instruments [2], restricting their applications. The rapid immunoassay for detecting CBZ with high sensitivity and specificity [6] overcomes the pitfalls of the traditional analytical methods [7]. A stable, specific, and cost-effective recognition receptor for CBZ is strongly required to replace the traditional immunoassays

Methods

Results

Discussion

Conclusion