pH stability improved electrochemical biosensor based on dopamine/aptamer imprinted polymer modified electrodes for simultaneous detection of four toxic metal ions

• Published in: Food control 2025-05, Vol.171, p.111099, Article 111099
• Main Authors: Sha, Jiahao, Hao, Liling, Fang, Xinyu, Zhu, Nianxin, Yang, Yihang, Peng, Kaiming, Ye, Tai, Cao, Hui, Gu, Huajie, Xu, Fei
• Format: Article
• Language: English
• Subjects: aptasensors; Aquatic creatures; Biosensor; Dopamine; electrochemistry; food safety; Imprinted polymer; oligonucleotides; pH stability; polymerization; polymers; quantitative analysis; shrimp; squid; Toxic metals; toxicity
• ISSN: 0956-7135
• DOI: 10.1016/j.foodcont.2024.111099

An enhanced pH-stable and highly sensitive electrochemical biosensor for the simultaneous detection of Cd2+, Pb2+, Hg2+, and As3+ was developed using dopamine/aptamer modified screen-printed electrodes. The aptamers of the four metal ions were initially immobilized on the surface of the corresponding working electrodes, where the specific conformation of the aptamers was induced in the presence of the toxic metal ions. Subsequently, the aptamer conformations were stabilized through electropolymerisation of dopamine, forming imprinted polymers to improve pH stability. After eluting the toxic metal ions with EDTA, the cavities left in the imprinted polymers selectively bound to the corresponding metal ions. Under optimized conditions, the developed electrochemical biosensor exhibits excellent specificity due to the specific ion conformation of dopamine imprinted polymers. Furthermore, the dopamine/aptamer imprinted polymer electrochemical sensor exhibited significantly enhanced pH stability compared to the electrochemical aptasensor, owing to the stabilization of the aptamer conformation by the imprinted polymers. The limits of detection (LOD) for the toxic metal ions were as follows: Pb2+ (1.4 μg L⁻1), Cd2+ (4.0 μg L⁻1), Hg2+ (1.9 μg L⁻1), and As3+ (6.6 μg L⁻1). The recovery rates in shredded squid and shrimp paste samples ranged from 87.5% to 108.8%, demonstrating the assay's excellent potential for the quantitative analysis of toxic metal ions in aquatic creatures. •The stability was improved by imprinting dopamine/aptamer on the electrode.•This work enables the simultaneous detection of four heavy metal ions.•The electrochemical sensor has satisfactory detection limits.