Innovative fluorescent aptasensor for sensitive tropomyosin detection in shrimp products using DNA-templated silver nanoclusters and catalytic hairpin assembly

Tropomyosin (TM), the major allergen in shellfish, is a common protein cause of allergenic diseases, hence a sensitive, efficient method for TM detection is urgently needed to protect allergy sufferers in food products. In this work, a novel fluorescent aptasensor for TM-sensitive detection based on DNA-templated silver nanoclusters (AgNCs) and catalytic hairpin assembly (CHA) was designed. With the rapid separation and enrichment of magnetic beads, the detection of TM was converted to the detection of cDNA (complementary DNA). Then the cDNA was utilized as the initiator to successfully trigger the CHA amplification technique, which ultimately formed double-stranded to induce high fluorescence signals by AgNCs. Specifically, the cDNA could trigger repeated cycles, which enabled signal amplification and enhanced aptasensor performance with an excellent linear relationship in a wide linear range from 0.1 to 50 μg/mL (R² = 0.9967) and a desirable low detection limit of 0.0179 μg/mL. It is worth noting that the method was successfully validated with high specificity and stability for detecting processed shrimp products, implying great potential in the field of allergen assay.