A Novel Biosensor Coupled With Microdialysis Device Based On 3D Gold Nanoparticles And Graphene Composite And Its Application In Neurotransmitter Determination

PART 1 Determination study of neutral transmitters on a novelelectrochemical biosensor and its applicationObjective:A biosensor constructed with graphene oxide(GO)and three-dimensional(3D)gold nanoparticles(GNPs)composite was developed.To establish a new system for detecting 5-HT and DA by highly sensitive 3D GNPs electrochemical sensor based on GO and consecutive adenines DNA(CA DNA)composite membrane.Method:To fabricate distribution-controllable GNPs,chloroauric acid was alternately electrodeposited on GO surface.Based on the above,3D GNPs were constructed using mercapto label-free DNA strands to improve the determination sensitivity of 5-HT and DA.The modification composite was characterized with scanning electron microscope(SEM),transmission electron microscopy(TEM),atomic force microscopy(AFM),X-ray photoelectron spectroscopy(XPS)and electrochemical methods.The electrochemical behaviors of 5-HT and DA at the modified electrode were studied by differential pulse voltammetry(DPV).Results:It was found the modified electrodes showed obvious electrocatalytics to the two objects.The oxide peak currents of 5-HT showed good linear relationships to concentrations in the range of 9.0×10~-88 mol/L~4×10~-66 mol/L and 6.0×10~-66 mol/L~4×10~-55 mol/L.And DA was in the range of4.0×10~-77 mol/L~7.0×10~-55 mol/L.Conclusion:The electrochemical biosensor can be applied in the real sample determination.The analytical speed is fast,the operation is simple,the sensitivity is high,the cost is low and the reproducibility is good.The experimental results are satisfactory.PART 2 Determination study of 5-HT and DA in real sample on a novelbiosensor coupled with microdialysis device and its applicationObjective:Microdialysis coupled with a novel electrochemical biosensor was used in the application.Achieve the purpose of dynamic monitoring of5-HT and DA in real samples.Method:The capacity-adjustable cell with 3D GNPs and GO composite modified electrode was designed to dynamic monitor the variation of 5-HT and DA.The recovery investigation of microdialysis probe was presented.Results:The modification conditions of the electrodes and the optimum pH of the supporting electrolytes for simultaneous determination of them was investigated.The quantitative relationships of 5-HT and DA between peak currents and their concentrations were established.The peak currents of 5-HT and DA were linear with the concentrations in the range of 6.0×10~-77 mol/L to4.0×10~-55 mol/L for 5-HT and from 9.0×10~-77 mol/L to 7.0×10~-55 mol/L for DA,respectively.The biosensor coupled with microdialysis was successfully applied to determine 5-HT and DA in the real samples with a spiked recovery of 82.0~118%.Conclusion:The biosensor coupled with microdialysis can be applied in the real sample determination.The method is simple,rapid and highly automated.The results are accurate and reliable.The experimental results are satisfactory.