Viologen-thiol self-assembled monolayers for immobilized horseradish peroxidase at gold electrode surface

• Published in: Electrochimica acta 1997, Vol.42 (6), p.961-967
• Main Authors: Li, Jinghong, Yan, Juchao, Deng, Qing, Cheng, Guangjin, Dong, Shaojun
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensors; Biotechnology; Chemistry; direct electrochemistry of proteins; Electrochemistry; Electrodes: preparations and properties; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General and physical chemistry; horseradish peroxidase; Ion selective electrodes; Methods. Procedures. Technologies; Self-assembled monolayers; Various methods and equipments; Viologen
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(96)00273-3

A stable, well-behaved self-assembled monolayer (SAM) of viologen-functionalized thiol was used to immobilize and electrically connect horseradish peroxidase (HRP) at gold electrode. Viologen groups in SAMs facilitated the electron transfer from the electrode to the protein active site so that HRP exhibited a quasi-reversible redox behavior. HRP adsorbed in the SAMs is very stable, and close to a monolayer with the surface coverage of 6.5 × 10 −11mol/cm 2. The normal potential of HRP is −580 mV vs Ag AgCl corresponding to ferri/ferro active center and the standard electron transfer rate constant is 3.41 s −1 in 0.1 M phosphate buffer solution (pH 7.1). This approach shows a great promise for designing enzyme electrodes with other redox proteins and practical use in tailoring a variety of amperometric biosensor devices.