Chemically Modified Electrode Surface Used Blue Copper Protein Adsorption Of Electrochemical And Sers Spectra Of Electrochemical Research

The azurin is a typical mononuclear blue copper protein, which is aprotein secreted by Pseudomonas aeruginosa, with a molecular weightof only14,000, and plays an important role of electron transfer in the invivo oxidation-reduction reactions. Previous researches about azurinmainly focused on the dynamic characteristics of electron transferprocess of this protein molecule mobilized on hydrophobic SAMssurface by conventional electrochemical means. Such researchescannot provide microscopic information at molecular level, andtherefore cannot reveal its reaction mechanism accurately and reliably.At present, SER(R)S has been developed into an important tool toinvestigate molecular structures and molecular interaction of redoxproteins.Based upon the previous research about azurin in our group, SERSand CV and EIS techniques has been used to characterize and analyzethe surface acid-base properties of self-assembled monolayers of2-mercaptosuccinic acid and12-mercapto-dodecanoic acid. Theseresearch works provides important information about azurinimmobilization on such hydrophilic SAMs surface. Then SERRS and CVtechniques were employed to investigate electrochemical behaviorand electron transfer of azurin immobilized on2-mercaptosuccinic acidSAMs modified gold electrodes.In this paper, the main content divided into the following threeparts:(1) Utilization of cyclic voltammetry (CV) and the electrochemicalimpedance method (EIS) techniques in characterization with solutionpH effect on12-mercapto-dodecanoic acid (MDA) self-assemblymonolayers (SAMs) modified on gold electrodes. EIS titration analytical method was also employed to calculate surface pKa of MDA SAMs.Furthermore the theory about hydrogen bonding interaction andelectrostatic effect was employed to explain the experimental results;(2) Based upon theoretical calculation of molecular spectroscopy,Raman and SERS spectroscopic characteristics of2-mercaptosuccinicacid (MSA) molecules were analyzed. Then CV and EIS techniques werealso employed to characterize the solution pH effect on MSA SAMsmodified on gold electrodes and evaluate the surface acid-baseproperty of MSA SAMs.(3) Electrochemical method were employed toexplore and optimize the appropriate immobilization conditions forazurin protein molecules on MSA SAMs modified gold electrodes. Thenelectrochemical in situ SERRS technique was employed to investigatethe effect of electrode potential on the SERRS spectra of azurinimmobilized on MSA SAMs modified gold electrodes.