A direct competitive assay-based aptasensor for sensitive determination of tetracycline residue in honey.

Tetracycline (TC) is a common antibacterial agent used for prevention and control of animal diseases. The increasing concern about TC residue in food demands high-performing analytical techniques for food quality assessment. Biosensors represent a promising tool for food safety analysis as they can fulfill some demand that the conventional methods do not attain. In this study, a novel colorimetric aptasensor was developed for sensitive detection of TC in honey. The aptasensor was based on a modified direct competitive enzyme-linked aptamer assay (dc-ELAA) scheme utilizing a 76 mer single-stranded DNA (ssDNA) aptamer selected by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The optimized aptasensor showed a good limit of detection (LOD of 0.0978 ng/mL), a wide linear range (0.1-1000 ng/mL) toward TC in honey, with good recoveries (92.09-109.7%) in TC-spiked honey, and was compared with an indirect competitive assay-based aptasensor and validated with a standard ELISA. The biosensor based on dc-ELAA with good limit of detection and simplicity can be applied for high-throughput detection of TC in food.