Design and Preparation of Nanostructured Prussian Blue Modified Electrode for Glucose Detection

Abstract

High sensitivity and anti-interference ability are critical parameters in glucose biosensor design, because of the complexity of blood composition. Prussian blue (PB) is a hexacyanoferrate with two different iron valences (+2 and +3) and was initially developed as a blue pigment in the 1700s (Bartoll, 2008). Recently researchers found that PB is an excellent material for use in the fabrication of glucose biosensors, because of its non-toxicity, high electrocatalytic activity, and low overpotential detection (Ricci & Palleschi, 2005; Karyakin et al., 2007; Wang, 2008). During glucose detection, hydrogen peroxide (H2O2) is produced via the enzymatic oxidation of glucose. Subsequently, PB reduces the H2O2 and transfers the electrons to generate a current response on the electrode surface. Thus, PB is the mediator of electron transfer in the detection process, making the electron sensitivity of PB a key component of biosensor performance. Chemical deposition and electrodeposition are the main processes used to synthesize a PB film on the electrode surface (Itaya et al., 1982; Zakharchuket al., 1995). However, the sensitivity of the electrode modified with a PB film cannot be controlled, because of difficulties in film construction. Millward et al. (2001) used a self-assembly approach to deposit a PB film on a gold electrode, which greatly accelerated the development of PBbased biosensors. The advantages of applying nanostructured materials for improving biosensor performance have been recognized in recent years, especially for improving sensitivity (Cella et al., 2010; Cao et al., 2010). The utilization of nanoparticles can enhance electrode performance, even if the same materials are used. We developed a PB nanostructure to produce a high sensitivity biosensor for glucose detection, which can be directly grown on the electrode surface. We previously synthesized PB nanoparticles on a platinum (Pt) electrode surface using a self-assembly approach (Liu et al., 2009). We found that the size and quantity of PB particles greatly affected H2O2 detection performance. After immobilization of the glucose enzyme, this type of biosensor was sensitive to trace concentrations of glucose in solution (Liu et al. 2009). However, it was difficult to form a regularly structured PB particle film, when synthesis was conducted via self-assembly. Thus, we further developed the self-assembly approach to deliver a novel method for obtaining a regular film of PB crystals, are thereby improving biosensor sensitivity and effectiveness.