A novel hydrogen peroxide sensor based on horseradish peroxidase immobilized in DNA films on a gold electrode

• Published in: Sensors and actuators. B, Chemical Chemical, 2006-04, Vol.114 (2), p.1001-1006
• Main Authors: Song, Yonghai, Wang, Li, Ren, Chunbo, Zhu, Guoyi, Li, Zhuang
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; DNA; Electrochemical sensors; Horseradish peroxidase; Hydrogen peroxide
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2005.07.061

A novel third-generation hydrogen peroxide (H 2O 2) biosensor was developed by immobilizing horseradish peroxidase (HRP) on a biocompatible gold electrode modified with a well-ordered, self-assembled DNA film. Cysteamine was first self-assembled on a gold electrode to provide an interface for the assembly of DNA molecules. Then DNA was chemisorbed onto the self-assembled monolayers (SAMs) of cysteamine to form a network by controlling DNA concentration. The DNA-network film obtained provided a biocompatible microenvironment for enzyme molecules, greatly amplified the coverage of HRP molecules on the electrode surface, and most importantly could act as a charge carrier which facilitated the electron transfer between HRP and the electrode. Finally, HRP was adsorbed on the DNA-network film. The process of the biosensor construction was followed by atomic force microscopy (AFM). Voltammetric and time-based amperometric techniques were employed to characterize the properties of the biosensor derived. The enzyme electrode achieved 95% of the steady-state current within 2 s and had a 0.5 μmol l −1 detection limit of H 2O 2. Furthermore, the biosensor showed high sensitivity, good reproducibility, and excellent long-term stability.