| Self-assembled monolayers (SAMs) have been pointed out by some researchers to present one of the most advanced form among the various methods to modify electrode surface. Biosensors can be fabricated through fixing the biologically active species (such as enzyme, antibody, cell etc.) to the surface of electrode by surface self-assembly monolayers technology, and which is being developed rapidly in recent years. On the other hand, the study on chemistry of mimetic enzyme has made great progress. The model compounds of superoxide dismutase (MSOD), which were designed and synthesized according to the active site of natural superoxide dismutase, have shown good superoxide dismutase like activities. Electrodes midified with MSOD are expected to be used as biosensors to detect superoxide, which will have potential applications in the fields of chemistry, biology, clinic diagnestics as well as environmental monitoring. In this thesis, we chose three kinds of MSOD (the complexes of benzimidazole derivatives coordinated with transiton metals), and fixed them onto SAMs. We also designed and synthesized a thiol compound containing terminal functional group imidazol, and constructed it onto SAMs by self-assembed monolayers technology. And the structures and electrochemical behaviors of the above MSOD and thiol modified electrodes were investigated. The main contents are listed as the following:1. Three complexes of benzimidazole derivatives coordinated with transiton metals, as the MSOD were chose as the research target and their molecular structure are given below. Their cyclic-voltammetric behaviors in solution were studied.2. 11-mercaptoundecanoic acid (MUA) was first used to fabricate the self-assmebled monolayer (SAM) on gold electrode, then dicyclohexylcarbodiimide (DCC) as coupling reagent was used to form amide linkage between the terminal carboxylic group of the self-assembled monolayer and the amino group of model compounds of superoxide dismutase. Through this method, three MSOD/MUA/Au self-assembled modified gold electrodes (Fe-MSOD/MUA/Au % Cu-MSOD/MUA/A^Mn-MSOD/MUA/Au SAMs) were prepared on the surface of the 11-mercaptoundecanoic acid SAMs. The XPS spectra, electrochemical cyclic voltammetry and electrochemical impendence spectra were employed to characterize the formation of molecular assembly system on electrodes, and the electrochemical redox characters of MSOD on SAMs have been studied.3. Fe-MSOD was fixed to the surface of MPA/Au SAMs by adopting DCC as coupling reagent. The electrochemical cyclic voltammetry and electrochemical impendence spectra were employed to characterize the structure of the modified electrode, and the result shows that the surface coverage (9) of MPA/Au and Fe-MSOD/MPA/Au modified electrodes are 94.9% and 98.0% respectively. Cyclic voltammetry has been employed to investigate the electrochemical reduction-oxidation of the SAMs modified electrodes in PBS (PH=7.0), and the result shows that the redox molecular concentration of Fe-MSOD on the surface is 5.67 X 10-11mol cm'2 at the scan rate 0.1v s-1.4. 11-Imidazol-l-yl-undecane-l-thiol was synthesized by employing two different starting materials, 11-bromo-undecane-l-ol and 11-bromo-undecanoic acid. The molecular structures of the intermediates and the target compound 11-Imidazol-l-yl-undecane-l-thiol were confirmed by 1H NMR, IR and MS.5. 11-Imidazol-l-yl-undecane-l-thiol was fabricated into the surface of gold electrode by self-assembly monolayers technology. The electrochemical cyclic voltammetry and electrochemical impendence spectra were employed to characterize the formation of molecular assembled monolayer on gold. The results shows that a closely packed and well ordered SAMs have been fabricated and itssurface coverage is over 99.9%.6. Electrochemical cyclic voltammetry has been employed to investigate the absorption behavior of 11-imidazol-l-yl-undecane-l-thiol /Au modified electrode to... |
