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

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.

Fluorescence and Colorimetric Dual-Signal Aptamer Sensor Based on Aptamer-Functionalized Fe3O4 Nanoparticles Decorated with Au and Pt Nanoparticles Combined with Fluorescently Labeled Aptamer Complementary Chain-Functionalized SiO2 Nanoparticles for Detecting the Insecticide Acetamiprid

“…27,28 Platinum nanoparticles (Pt NPs) catalyze the oxidation of peroxidase substrates to produce a color change, providing an important tool for colorimetric biosensing, and have been widely used in food safety detection. 29,30 In this study, Au NPs and Pt NPs were comodified on the surface of 1). This study provides technical support for the rapid detection of ACE residues in vegetables and has a certain reference value for the construction of other pesticide detection sensors.…”

“…Ferroferric oxide (Fe 3 O 4 ) nanoparticles have good magnetic response and peroxidase-like activity and have been widely used in many fields such as biosensing, food safety, and disease diagnosis. − Gold nanoparticles (Au NPs) are widely used in the construction of fluorescence and colorimetric sensors because of their easy size control, good biocompatibility, excellent fluorescence quenching ability, and peroxidase activity. , Platinum nanoparticles (Pt NPs) catalyze the oxidation of peroxidase substrates to produce a color change, providing an important tool for colorimetric biosensing, and have been widely used in food safety detection. , In this study, Au NPs and Pt NPs were comodified on the surface of Fe 3 O 4 to obtain Fe 3 O 4 –Au/Pt, and the sulfhydrated Apts were combined with Fe 3 O 4 –Au/Pt through groups to form the Fe 3 O 4 –Au/Pt-Apt probe.…”