Label-Free Detection of Doxorubicin in Lake Water by an Electrochemical Aptamer Biosensor

The application of electrochemical sensors to the detection of real samples is hampered by the fact that the electrode surface is often prone to adsorption of other substances that cause a non-specific current response. In addition, electroactive substances in the actual sample are prone to redox reactions on the electrode surface and affect the detection of target molecules. In this paper, we constructed a novel DOX sensor with excellent selectivity using an aptamer-modified gold electrode and used it for the label-free rapid detection of DOX in lake water. DOX molecules in solution can be captured by the aptamers immobilised on the surface of the gold electrode, followed by the DOX molecules getting electrons on the surface of the electrode and undergoing a reduction reaction. Aptamers give electrochemical sensors excellent sensitivity and selectivity. Finally, the electrochemical aptamer biosensor was successfully applied to detect DOX in lake water with a detection limit of 30 nmol/L and a detection range of 30 nmol/L–10 μmol/L.