Amperometric Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Entrapped in Titania Sol-Gel Film on Screen-Printed Electrode

Abstract

We report the fabrication of disposable and flexible Screen-Printed Electrodes (SPEs). This new type of screen-printed electrochemical platform consists of Ag nanoparticles (AgNPs) and graphite composite. For this purpose, silver nanoparticles were first synthesized by a chemical reduction method. The morphology and structure of the AgNPs were analyzed using a Scanning Electron Microscope (SEM) and UV-Visible spectroscopy. Graphite was chosen as the working electrode material for the fabrication of a thick-film. The fabrication of a screen-printed hydrogen peroxide biosensor consisting of three electrodes on a polyethylene terephthalate (PET) substrate was performed with a spraying approach (working, counter and reference: enzyme electrode, graphite, pseudo reference: Ag/AgCl). This biosensor was fabricated by immobilizing the peroxidase enzyme (HRP) in a Titania sol-gel membrane which was obtained through a vapor deposition method. The biosensor had electrocatalytic activity in the reduction of H2O2 with linear dependence on H2O2 concentration in the range of 10-5 to 10-3 M; the detection limit was 4.5 × 10-6 M.