Study on a nano-porous gold/polyamidoamine (NPG/PAMAM)-based electrochemical aptamer biosensor for the detection of ochratoxin a in the red wine

Abstract

In this study, a novel electrochemical aptamer sensor for detecting ochratoxin A (OTA) was constructed. First, a gold-copper alloy film was prepared via electrochemical deposition, and copper was selectively dissolved in constant potential mode for obtaining the nano-porous gold modified screen-printed carbon electrodes (NPG/SPCE). Then, 2-mercaptoethylamine was dropped on the NPG/SPCE surface and Au-S covalent bonds were formed for immobilizing the metal. Glutaraldehyde as cross-linking agent was added, which resulted in immobilization and attachment of PAMAM to the 2-mercaptoethylamine through the dehydration condensation reaction. During the preparation process, the nano-porous gold and PAMAM-modified layers were characterized by SEM, XRD, and IR spectroscopy, respectively. The characterization results showed that the nano-porous gold and PAMAM composite films were successfully modified. Finally, the OTA aptamer was cross-linked with PAMAM by glutaraldehyde to complete construction of the Apt/PAMAM/NPG/SPCE sensor. The electrochemical performance of this sensor was tested in ochratoxin A solutions with the DPV method. The results showed that the sensor’s reproducibility, stability, and specificity were good. The spiked recoveries in red wine ranged from 99.65%∼101.6%, with a linear range of 0.5 ng/mL∼20 ng/mL and a minimum detection limit of 0.141 ng/mL. Thus, the novel biosensor may provide a promising tool for the trace detection of OTA.

Keywords:

• Ochratoxin A
• nano-porous gold
• PAMAM
• aptamer
• biosensor

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported from the project of Youth Fund for Science and Technology Research in Hebei Universities [grant number: QN2020194], the project of Tangshan Science and Technology Plan [grant number: 22130221G], the Project of Youth Fund for National Natural Science Foundation of China [grant number:32001791] and the project of Youth Fund for Science and Technology Research in GuiZhou Universities [grant number: QianJiaoJi[2022]358].