A promising biosensing-platform based on bismuth oxide polycrystalline-modified electrode: Characterization and its application in development of amperometric glucose sensor Shou-Nian Ding a,b, ⁎, Dan Shan b,c, ⁎, Huai-Guo Xue b,c , Serge Cosnier d a School of Chemistry & Chemical Engineering, Southeast University, Nanjing, 211189, China b Key Laboratory of Environmental Materials & Environmental Engineering of Jiangsu Province, Yangzhou 225002, China c School of Chemistry & Chemical Engineering, Yangzhou University, Jiangsu, 225002, China d Départment de Chimie Moléculaire UMR-5250, ICMG FR-2607, CNRS Université Joseph Fourier, BP-53, 38041 Grenoble, France abstract article info Article history: Received 1 December 2009 Received in revised form 11 May 2010 Accepted 16 May 2010 Available online 11 June 2010 Keywords: Bismuth oxidase Inorganic matrix Glucose oxidase Biosensor Nano-structured bismuth oxide (nano-BiO x ) is a suitable material for enzyme immobilization owing to its attractive properties, such as large specific surface area, suitable permeability of the resulting film, the high biocompatibility, and as well as photovoltaic effect from semiconductor nanoparticles. Thus, a new type of amperometric glucose biosensor based on nano-BiO x was constructed. The amperometric detection of glucose was assayed by potentiostating the GOD/nano-BiO x electrode at 0.5 V to oxidize the enzymatically generated hydrogen peroxide. The proposed biosensor provided a linear response to glucose over a concentration range of 1 × 10 -6 M to 1.5×10 -3 M with a sensitivity of 51.0 ± 0.4 mA/(M cm 2 ) and a detection limit of 4 × 10 -7 M based on S/N = 3. The apparent Michaelis–Menten constant was calculated to be 2.9×10 -3 M. In addition, characterization of nano-BiO x and modified electrode was performed by FT-IR spectroscopy, Raman spectroscopy, scanning electron microscope (SEM) and rotating-disk electrode (RDE) voltammetry. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Bismuth oxide (BiO x ) is an interesting material, very important in modern solid-state technology and fascinating to scientists, owing to its unique structures and physical properties like the large energy band-gap, high refractive index, dielectric permittivity and high oxygen-ion conductivity, as well as marked photoconductivity and photoluminescence [1–3]. These special features of BiO x make it suitable for a large range of applications, such as gas-sensors, optical coatings, photovoltaic cells and microwave integrated circuits [4–6]. In addition, BiO x is nontoxic and has excellent chemical inertness and biocompatibility. Since the discovery of carbon nanotubes [7], nano-structured- materials have received intensive research interest due to their unique properties and potential applications in, for example, nanoscale electronics, optoelectronics, and magnetics [8]. Nano- sized bismuth oxide (nano-BiO x ) shows greater advantages and novel characteristics than regular sized particles, such as the much higher specific surface and greater surface free energy, which are favorable for the biomolecules adsorption. Encouraged by these properties of nanoscaled-material, in this work, we aim to continu- ously extend the application of nano-BiO x into the bioelectrochemical research area to construct a suitable platform for biosensing. Structural and morphology characterization, FT-IR, Raman scattering and SEM studies performed on the synthesized nano-BiO x are presented. The permeation property of the nano-BiO x modified electrode was investigated by rotating-disk electrode experiment (RDE). Since glucose oxidase (GOD) is well-studied, inexpensive, stable and practically applied in clinical and chemical analyses [9], this enzyme was used as a model enzyme to explore the ability of the synthesized nano-BiO x as a matrix for enzyme immobilization in the design of an amperometric glucose biosensor. 2. Experimental 2.1. Reagents Glucose oxidase (GOD) (EC 1.1.3.4, Type II, 108 U/mg) from Aspergillus niger was purchased from Amresco. Nanostuctured bismuth oxide (nano-BiO x ) samples were synthesized according to an earlier reported procedure [10,11]. All other chemicals were of analytical grade and used without further purification. Phosphate Bioelectrochemistry 79 (2010) 218–222 ⁎ Corresponding authors. Shan is to be contacted at School of Chemistry & Chemical Engineering, Yangzhou University, Jiangsu, 225002, China. Fax: + 86 514 87975244. Ding, School of Chemistry & Chemical Engineering, Southeast University, Nanjing, 211189, China. Fax: + 86 25 52090621. E-mail addresses: snding@seu.edu.cn (S.-N. Ding), danshan@yzu.edu.cn (D. Shan). 1567-5394/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.bioelechem.2010.05.002 Contents lists available at ScienceDirect Bioelectrochemistry journal homepage: www.elsevier.com/locate/bioelechem