A colorimetric and fluorescent gold nanoparticle-based dual-mode aptasensor for parvalbumin detection

Food allergy has risen as a worldwide food safety concern due to the increasing prevalence over the last decades. It's in urgent need to develop straight yet sensitive detection methods for food allergens to help people avoid the potential risks imposed by food allergy. Here, we developed a dual-mode aptasensor that gave both colorimetric and fluorescent readouts in response to parvalbumin (PV), a major allergen in fish. The aptasensor was constructed by hybridizing the aptamer modified gold nanoparticles (AuNP-APT), the complementary short chain modified gold nanoparticles (AuNP-CS1) and the fluorescent dye-labeled complementary short chain (FAM-CS2). The presence of PV led to disassembly of the aptasensor through competitive interaction between APT and PV, which resulted in a change in the solution color of the AuNPs and a recovery of the once quenched fluorescence signals of FAM-CS2. The aptasensor exhibited a colorimetric response in the PV concentration range of 2.5-20 mu g/mL and a linear fluorescent response in the PV concentration range of 2.38-40 mu g/mL. Moreover, the aptasensor showed encouraging specificity, precision, accuracy as well as efficiency in real fish sample detection, which held great potential in recognition and analysis of food allergens.