A novel fluorescent structure-switching aptasensor for the sensitive detection of acrylamide based on AuNPs-assisted separation of ssDNA

Fluorescent aptasensor was developed for acrylamide (AAm) detection by utilizing the adsorption effect of Au nanoparticles (AuNPs) and fluorescence properties of SYBR Green I (SGI) towards double-stranded DNA (dsDNA). Compared to the binding of aptamer with AAm, the higher affinity of aptamer with cDNA may facilitate a structure switching from the aptamer/AAm complex to aptamer/cDNA dsDNA. The free aptamers were adsorbed onto AuNPs and separated by centrifugation. Subsequently, SGI was introduced as a fluorescent reporter for quantitative detection. Compared to conventional AuNPs-based colorimetric detection, the sensitivity of this strategy was improved by 3.18-fold in the range of 0.005–50 mg/L with a low detection limit of 4.68 μg/L. The method has been successfully applied to analyze fried twists and biscuits. Notably, it is a low-cost and general method that provides guidance for the development of rapid screening technology in the field.