High-efficient selection of aptamers by magnetic cross-linking precipitation and development of aptasensor for 1-aminohydantoin detection

Accurate and rapid detection of nitrofurantoin metabolite 1-aminohydantoin (AHD), as one of the tissue-bound toxic metabolites in foods, is crucial. In this study, a fluorescent aptasensor was constructed for the detection of AHD, using anti-AHD aptamers firstly obtained by high-efficiency magnetic crosslinking precipitation (MCP)-SELEX. The AHD-specific aptamers were optimized and identified for their binding affinity and specificity using fluorescence-based assays and molecular dynamics simulations. The truncated aptamer AHD50-1, which exhibited highest affinity (Kd = 86 nM) and an excellent specificity, was applied to the construction of fluorescent aptasensor. Under optimized conditions, the aptasensor showed a low limit of detection (0.2 ng/mL) and a wide dynamic linear range (0.25–150 ng/mL). For the five types of samples (pork, beef, shrimp, fish and honey), the recoveries ranged from 89.4% to 110.04%, with coefficients of variation ranging from 1.43% to 14.46%. These results obtained by the proposed aptasensor corroborate very well with the method of HPLC for detection of AHD, indicating that the developed aptasensor provides an efficient and promising sustainable strategy for monitoring AHD in animal derived food.