A multifunctional polyvalent DNA scaffolds-based photothermal aptasensor for visible and portable detection of aflatoxin B1

Aflatoxin B1 contamination poses severe threats to food safety, vitally requiring reliable assays. Biosensors are effective but subject to unsatisfactory signal conversion efficiency owing to their usage of the monovalent probes with redundant materials and procedures. Herein, we developed a photothermal aptasensor, which combined multifunctional polyvalent DNA scaffolds with thermal imaging for the portable detection of aflatoxin B1. The aptasensor was conferred with favorable properties of specific recognition, surface modification and signal amplification by the polyvalent DNA scaffolds, thereby showed enhanced analytical performance with simplified procedures. Moreover, the detection potential of the aptasensor was further improved by introducing Cu x S nanoparticles to provide intuitive temperature output for portable devices analysis. Consequently, AFB1 could be quantified in a wide range of 1–500 ng/mL with the detection limit of 0.75 ng/mL, merely using common thermometer. For food samples, the spiked recoveries of the proposed method ranged from 93.5 % to 108.7 % with relative standard deviation from 2.9 % to 6.3 %. These results were in agreement with the high-performance liquid chromatography method, demonstrating the good accuracy of this method. Therefore, this method is expected to be extended as a universal detection strategy for food hazards analysis. • A portable, photothermal aptasensor for aflatoxins B1 (AFB1) was developed. • The detection performance was effectively improved by the polyvalent scaffolds. • The portable analysis devices were used for on-site and visible detection of AFB1. • The proposed aptasensor was successfully applied to detect AFB1 in food samples.