Screening of broad-spectrum aptamers to construct an electrochemical aptasensor for the sensitive detection of tetracycline antibiotic residues in milk

• Published in: Sensors and actuators. B, Chemical Vol. 398; p. 134765
• Main Authors: Bai, Mengyuan, Yue, Fengling, Zhai, Shengxi, Hu, Mengjiao, Qi, Guangyu, Chen, Shihao, Li, Baoxin, Sun, Xia, Guo, Yemin, Marrazza, Giovanna
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024
• Subjects: Broad-spectrum aptamer; Combination mechanism; Electrochemical aptasensor; GO-SELEX; Milk samples; Tetracycline antibiotics; Combination mechanism; GO-SELEX; Electrochemical aptasensor; Milk samples; Tetracycline antibiotics; Broad-spectrum aptamer
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2023.134765

Broad-spectrum aptamer has been shown to be an important probe for antibiotic multi-residue detection. In this study, we successfully screened a broad-spectrum aptamer (Apt-T1) that can recognize TCs with the same core structure using the graphene oxide (GO)-SELEX. Then Apt-T1 was truncated by molecular docking simulation to obtain an aptamer (Apt-T1–2) with higher specificity and affinity with a dissociation constant of 4.27–7.20 nM. On this basis, an electrochemical aptasensor based on Apt-T1–2 was constructed to achieve sensitive detection of TCs. Fe/ Zn-doped montmorillonite was synthesized by cation exchange technique for amplifying sensor signal. Under optimized conditions, the aptasensor showed a limit of detection of 0.46 nM and a linear range of 1–10,000 nM with a correlation coefficient (R2) of 0.989. Finally, the effects of the main components (fat, protein, Na+ and Ca2+) in milk on the electrochemical signal were investigated, and it was clear that fat and protein had a negative effect and so they were removed. The method was used to the determination of TCs in milk with recoveries of 98.26%− 104.15%, which revealed its potential application for sensitive analysis in food safety control and also provided a new method for multi-residue detection of antibiotics in milk. •The broad-spectrum aptamers of TCs were firstly screened and truncated.•An electrochemical aptasensor was successfully constructed with LOD of 0.46 nM.•Fe/Zn doped montmorillonite was used to amplify the sensor signal.•The negative effect of fat and protein on electrochemical signal was clarified.•Proposed assay is less expensive and faster than existing TCs detection methods.