Electrochemical Detection Of Three Small Molecules With Reductive Property And Study On Their Repair Function On Injured Vascular Endothelial Cells

This thesis introduces the principle,classification,application and development trend of electrochemical sensors and conductive polymer modified electrodes.The function,injury and repair of vascular endothelial cells are summarized.Three electrochemical sensors for the detection of acetaminophen（AP）,folic acid（FA）and luteolin（LE）have been established by combining nanocomposite materials with conductive polymers.Taking damaged vascular endothelial cells as the research object,the repair function of the above three small molecules on different damaged cells is investigated.The main contents of the research work are listed as follows:1.Poly（caffeic acid）-CoP nanoparticle composite film,PCA-CoP,was successfully prepared on the surface of glassy carbon electrode（GCE）by potentiostatic deposition and cyclic voltammetry.It was characterized by scanning electron microscope-electronic energy spectroscopy（SEM-EDS）,fourier transform infrared spectroscopy（FTIR）and X-ray photoelectron spectroscopy（XPS）.The fabricated GCE/PCA-CoP electrode exhibited a good catalytic effect on the electrochemical reaction of AP.Under the optimal experimental conditions,the anode peak current on the differential pulse voltammetric curve had a good linear relationship with the concentration of AP between 0.05μM and 50μM,and the limit of detection（LOD）was 10 n M.The oxidative injury of human umbilical vein endothelial cells（HUVECs）was induced by the 1-h contact with H₂O₂at different concentration.The injured cells were treated with 100μM AP for 12 h.The microscope images confirmed that AP exerted a certain repair effect on oxidative injured HUVECs.Electrochemical measurement results showed that the more serious the oxidative injury of HUVECs was,the less AP content in the growth medium was.It means that more AP molecules was taken by the cells that suffered from the more serious injury.2.Nanocomposite composed of multi-walled carbon nanotubes and Cu（II）,MWCNTS-Cu（II）,was prepared by ultrasound auxiliary assembly technigue.The nanomaterial was characterized by transmitting electron microscopy（TEM）,SEM-EDS,IR,and XPS.FA displayed a good electrochemical response on GCE/MWCNTS-Cu（II）in 0.5 M H₂SO₄solution.Under the optimal experimental conditions,the DPV anodic peak current was propotional to the concentration of FA in the range of 0.5-7.5μM and 10-100μM,and the LOD was calculated to be 29 n M.The FA content in the commercially available folic acid tablet was determined,and the accuracy was satisfactory.HUVECs were injured by the 2-h contact homocysteine at different concentration.The injured cells were treated with 100μM FA for 12 h.The microscope images revealed the repair function of FA.It was concluded from the electrochemical measurement results that the seriously injured cells took more FA from the growth medium.3.Poly（3,4-ethylenedioxythiophene）（PEDOT）was successfully synthetized on the MWCNTs modified-GCE surface via cyclic voltammetry.The prepared GCE/MWCNTs-PEDOT electrode showed a good catalytic effect on the electrochemical response of LE.Under the optimal experimental conditions,the DPV anodic peak current varied directly with the LE concentration in the range of 0.05-5μM and 10-100μM,and the LOD was 17 n M.Three-hour contact with Na Cl at high concentration resulted in the damage of HUVECs.10μM LE was used to treat the injured cells for 12 h.The microscope observation and electrochemical measurement results showed that the injured HUVECs took LE from the growth medium and the celluar activity was recovered to a certain extent.