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One-step and real-time detection of Hg2+ in brown rice flour using a biosensor integrated with AC electrothermal
Haochen Qi1, Lei Xiao2, Jayne Wu3
1College of Electrical and Electronic Engineering, Wenzhou University, Wenzhou 325035, China; State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China.
Abstract:
Mercury (Hg2+) is one of the most toxic heavy metals in farm products, so rapid detection of trace Hg2+ has always been sought after with high interest. Herein, we report a biosensor to specifically recognize Hg2+ in leaching solutions of brown rice flour. This sensor is simple and of low cost, with a very short assay time of 30 s. Another merit is the ultra-low limit of detection (LOD) at fM level. In addition, the specific aptamer probe realizes a good selectivity above 105: 1 against the interferences. This sensor is developed based on an aptamer-modified gold electrode array (GEA) for capacitive sensing. Alternating current electrothermal (ACET) enrichment is induced during the AC capacitance acquirement. Thus, the enrichment and detection are coupled as a single step, and pre-concentration is needless. Owing to the sensing mechanism of solid-liquid interfacial capacitance and ACET enrichment, Hg2+ level can be sensitively and rapidly reflected. Also, the sensor has a wide linear range from 1 fM to 0.1 nM and a shelf life of 15 days. This biosensor shows advantages on overall performance, enabling easy-to-operate, real-time, and large-scale Hg2+ detection in farm products.
