Simultaneous aptasensor assay of ochratoxin A and adenosine triphosphate in beer based on Fe3O4 and SiO2 nanoparticle as carriers

Abstract

In this work, a chemiluminescence (CL) method based on dual aptasensors using Fe₃O₄ and SiO₂ nanoparticles (NPs) as carriers is developed for the simultaneous detection of ochratoxin A (OTA) and adenosine triphosphate (ATP) in beer. Amino-modified Fe₃O₄ NPs and SiO₂ NPs are prepared as carriers with excellent water-dispersibility, uniform particle size, and good modification. Fe₃O₄ NPs and SiO₂ NPs can be easily separated by magnetism and centrifugation when they are applied to detect multiple analytes. The aptamers of OTA and ATP can hybridize with complementary capture DNA pre-immobilized on Fe₃O₄ and SiO₂ nanoparticle carriers, respectively. The added target molecules, OTA or ATP, act as specific competitors and will pull down the corresponding aptamer bound with capture DNA, forming target–aptamer complexes. By separately detecting the decrease in CL value from the guanines in the aptamer immobilized nanoparticle carriers, the amounts of OTA and ATP can be indirectly quantitatively detected. This method has a wide linear range for OTA (2.5 μM–12.5 nM) and ATP (2 μM–10 nM) and the experimental results show that the detection limits of OTA and ATP are 9.02 nM and 9.31 nM, respectively. Most importantly, the excellent recovery rates of OTA and ATP are between 94.4% and 101.2% in spiked beer samples. The work reveals the great potential of simultaneous analysis assay for OTA and ATP based on different nanoparticle carriers in diverse foods.