Engineering Novel Aptameric Fluorescent Biosensors for Analysis of the Neurotoxic Environmental Contaminant Insecticide Diazinon from Real Vegetable and Fruit Samples

Abstract

Background: Diazinon is a widely used organophosphorus neurotoxic insecticide. It is a common environmental contaminant and a hazardous agri-waste. Its detection is critical to control entry into food systems and protect the environment. Methods: In this study, three single-stranded DNA aptamers specific for diazinon were discovered using the systematic evolution of ligands by the exponential enrichment (SELEX) process. Since aptamer-based sensors are quick and straightforward to analyze, they could potentially replace the time-consuming and labor-intensive traditional methods used for diazinon detection. Results: Here, we show the engineering of novel sensors for diazinon detection with a high affinity (Kd), specificity, and high sensitivity at the ppb level. Moreover, the aptamers were helpful in the simultaneous detection of two other structurally relevant insecticides, fenthion, and fenitrothion. Furthermore, the real vegetable and fruit samples confirmed the specific detection of diazinon using DIAZ-02. Conclusions: We developed novel biosensors and optimized the assay conditions for the detection of diazinon from food samples, such as vegetables and fruit. The biosensor could be adopted to analyze toxicants and contaminants in food, water, and nature as point-of-care technology.

Keywords

• food contaminant
• selex
• insecticide detection
• ssdna aptamer
• fluorescence
• biosensor
• binding affinity
• dissociation constant