Electrochemistry Of Chitosan/Ru(bpy)₃²⁺/SiO₂ Nanoparticles On The Surface Of Chitosan Functionalized Carbon Nanotube Modified Electrode Luminescence Analysis Characteristics Research

Ru(bpy)32+/SiO2 nanoparticles are widely used in the field of electrochemiluminescence(ECL)analysis because of their good biocompatibility,good optical properties and easy chemical modification.However,the poor conductivity of the silica nanomatrix greatly limits their further improvement on their ECL analytical performances.Based on the combination of electrochemical deposition method and supramolecular self-assembly technology,developed a new functionalization method for carbon nanotubes,a hydrophilic carbon nanotube composite film modified electrode were prepared in situ on the surface of the glass carbon electrode.The composite membrane modified electrode exhibits good electrochemical and ECL activity of Ru(bpy)32+/SiO2 nanoparticles,which had important theoretical and practical significance for improving the ECL characternstics of Ru(bpy)32+/SiO2 nanoparticles.This thesis is composed of two parts:review and research report.In first chapter,after a brief introduction of carbon nanotubes and their characteristics,the functional methods of carbon nanotubes in recent years and their new progress in the field of electroanalytical chemistry are introduced emphatically.The research report is composed of the following two parts:1.The investigation into the ECL analytical performance of chitosan/Ru(bpy)32+/SiO2 composite nanoparticles on the surface of PSS/chitosan functional carbon nanotubes modified electrode.Based on the combination of electrochemical deposition method and supramolecular self-assembly technology,the Nafion/MWNTs core@chitosan/PSS shell composite membrane modified glass carbonelectrode was successfully prepared in this work.The physical structure of the composite membrane modified electrode and electrochemical properties of chitosan/Ru(bpy)32+/SiO2 composite nanoparticles on the surface of this modified electrode were studied by scanning electron microscope(SEM),electrochemical and ECL techniques.The results showed that the ECL signal of CRuS NPs measured by the composite modified electrode is 10 times stronger than that of the Nafion/MWNTs modified electrode.Then,based on the distinguishing effect of CRuS NPs towards DNA molecular beacons(H1,H2)and the double-stranded DNA,which was formed from the reaction of miRNA catalytic H1 and H2 hybridization reaction,and the pre-concentration effect of CRuS NPs on the surface of composite membrane modified electrode,a highly sensitive ECL method for let-7a detection was developed.Under optimum conditions,the concentration of let-7a was linear with the ECL signals in the range of 1.0×13-9.0×10-14mol/L.This proposed method was also used to determine the let-7a in human serum samples.2.The investigation into the ECL analytical performalce of clitosan/Ru(bpy)32+/SiO2 composite nanoparticles on the surface of AuNPs/chitosan functionalized carbon nanotubes modified electrode.According to similar procedure of research report 1 for preparing the modified electrode as well as the electrostatic interaction of HAuCl4 with chitosan and the porous template effect of chitosan gel layer on carbon nanotubes,the Nafion/MWNTs core@chitosan/AuNPs shell composite membrane modified glass carbon electrode was successfully prepared by reducing HAuCU with NaBH4.The physical structure of the composite membrane electrode and ECL properties of chitosan/Ru(bpy)32+/SiO2 composite nanoparticles on the surface of the membrane electrode were studied by scanning electron microscope(SEM),electrochemical and ECL techniques.The related results showed that,AuNPsin the chitosan/Nafion/MWNTs membrane can provide electronic transmission channelsto enhance the conductivity of composite membranes,so the ECL signal of CRuS NPs measured by the composite membrane modified electrode is 7 times stronger than that of the Nafion/MWNTs membrane electrode.According to the differentiated interaction between CRuS NPs and ssDNA probe and ssDNA/miRNA complex,a ECL method for detecting miRNA is developed.Under optimum conditions,the concentration of miRNA was linear with the ECL intensity in the range of 1.0×10-13-9.0×10-14mol/L.This method was successfiully used to detect miRNA in human serum samples by the recovery rate of 101%.