| In this paper,the research status and progress of marine toxins electrochemical biosensor,nanoelectrode ensembles and chemically modified electrodes are reviewed.Polypyrrole?PPy?and poly?thionine??PTh?were modified on the surface of conventional size gold electrode by cyclic voltammetry electropolymerization method,respectively.Two okadaic acid?OA?immunosensors were prepared respectively based on Au/PPy and Au/PTh for quantitative detection of OA.Three-dimensional gold nanoelectrode ensembles?3DGNEEs?were fabricated by electroless deposition and electrodeposition based on a template method.Then electrochemical and morphological characterizations of 3DGNEEs were performed.A high-sensitivity OA immunosensor was developed based on 3DGNEEs/PTh for quantitative detection of OA.A gold electrode modified with PPy was created by electropolymerization,and an OA immunosensor was prepared based on Au/PPy.The parameters of PPy electropolymerization,glutaraldehyde cross-linking,antibody immobilization,BSA blocking and the time of immune reaction were optimized during the fabrication progress of the immunosensor.The OA concentration was tested by square wave voltammetry?SWV?with an Au/PPy/GA/anti-OA/BSA immunosensor.The limit of detection is 2.69×10-11 g/mL?S/N=3?with a linear range of 1×10-101×10-7 g/mL.A gold electrode modified with PTh was prepared by electropolymerization,and an OA immunosensor was prepared based on Au/PTh.The parameters of PTh electropolymerization,glutaraldehyde cross-linking,antibody immobilization,BSA blocking,test systems and the time of immune reaction were optimized during the fabrication progress of the immunosensor.A suitable equivalent circuit was built to simulate the impedance spectra when the OA concentration was detected by electrochemical impedance spectroscopy?EIS?,and the limit of detection is 3.41×10-10g/mL?S/N=3?with a linear range of 1×10-91×10-7 g/mL.The detection limit of immunosensor by square wave voltammetry?SWV?is 1.81×10-11 g/mL?S/N=3?with a linear range of 1×10-101×10-7 g/mL.3DGNEEs were fabricated by chemical deposition and electrodeposition using a polycarbonate membrane as a template.The electrodeposition parameters were optimized.The morphology and composition of 3DGNEEs were characterized by scanning electron microscopy?SEM?and energy dispersive X-ray analyzer?EDX?.The active area of 3DGNEEs was calculated using the redox electricity method,cyclic voltammetry,and electrochemical impedance spectroscopy,respectively.An OA immunosensor was developed based on 3DGNEEs/PTh.The detection limit of immunosensor by EIS is 2.65×10-12 g/mL?S/N=3?with a linear range of 5×10-121×10-9g/mL.And the detection limit of immunosensor by SWV is 3.20×10-15 g/mL?S/N=3?with a linear range of 1×10-121×10-7 g/mL.This immunosensor has a lower limit of detection and a wider linear range compared to other OA immunosensors based on conventional size gold electrode.The average recovery of the OA immunosensor for real mussel samples is 110.5%. |
PDF Full Text Request