Phytic Acid-Based Layer-by-Layer Assembly for Fabrication of Mesoporous Gold Film and Its Biosensor Application

Abstract

Phytic acid was introduced as a binder to construct a controllable structure at an electrode surface. In this paper, phytic acid and gold nanoparticles were assembled onto the surface of a gold electrode layer-by-layer to form a three-dimensional mesoporous gold interface. Then, a high sensitive horseradish peroxidase (HRP) biosensor was prepared based on the proposed mesoporous interface. Atomic force microscopy, Raman spectroscopy, and electrochemical impedance spectroscopy were applied to characterize the process of forming nanofilms. Hydrogen peroxide was detected with the aid of a hydroquinone mediator to transfer electrons between the electrode and the HRP. The immobilized HRP displayed the feature of a peroxidase and gave an excellent electrocatalytic response to the reduction of . The biosensor showed a linear response to over a concentration range from to with a detection limit of . The Michaelis–Menten constant was estimated to be . The biosensor exhibited high sensitivity, good accuracy, and acceptable stability.