| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 93 === Reagentless biosensors are fabricated as a developing trend of biosensors. One of the main issues for reagentless sensors is to promote electron transfer between a transducer surface and a biological recognition component. In order to fabricate a electrode displaying both electroactive property and being able to immobilize enzymes, a ferrocenyl disulfide compound was synthesized to modify the electrode surfaces by the mixed self-assembled monolayer technique. These monolayers were characterized by static contact angle measurement, FTIR and ESCA and the electrochemical property of modified electrodes were analyzed using the potentialstat. The measurement indicated that the mixed monolayers increased their hydrophilicity with increasing the fractions of ferrocenyl disulfide and they were immobilized on gold surfaces via S-Au bonding. In electrochemical analysis, the current could be increased with increasing the fractions of ferrocenyl disulfide when using HClO4 as the supporting electrolyte. The operating voltage was raised as the hydrophobic groups increased. The peak separation (ΔE) was around 59 mV and the currents were found to be linear increment with the scan rate, showing the reversible and direct controlling electron transfer on the modified electrode. On the evaluation for enzyme biosensing application, hydrophobic ClO4- ions as the supporting electrolyte demonstrated a better response than hydrophilic HPO42- ions.
Another modification on the electrodes was developed by the Schiff base method to bind the ferrocene on the electrode surfaces, therefore enhancing the current response in aqueous solution in comparison with the amide base method. The hydrogen bondings among the amide bonds were supposed to dilute the ferrocene currents. Consequently, the FcCN(CH2)2S-Au electrode can be applied to biosensor manufacture.
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