A H2O2 Biosensor Based on Immobilization of Horseradish Peroxidase in a Gelatine Network Matrix

Abstract: A simple and promising H 2 O 2 biosensor has been developed by successful entrapment of horseradish peroxidase (HRP) in a gelatine matrix which was cross-linked with formaldehyde. The large microscopic surface area and porous morphology of the gelatine matrix lead to high enzyme loading and the enzyme entrapped in this matrix can retain its bioactivity. This biosensor exhibited a fast amperometric response to hydrogen peroxide (H 2 O 2 ). The linear range for H 2 O 2 determination was from 2.5×10 -5 to 2.5×10 -3 M, with a detection limit of 2.0×10 -6 M based on S / N = 3. This biosensor possessed very good reproducibility . Keywords: H 2 O 2 biosensor, horseradish peroxidase, gelatine matrix. Introduction During the past few decades, numerous investigations have been carried out on electrochemical biosensors, due to the possibility of combining speed, selectivity and sensitivity in a low cost chemical analysis method [1,2,3]. Our target is to construct the simplest possible biosensor which can be used for measurement purposes, consisting of only a thin layer of protein such as an enzyme or antibody. Many materials, such as chitosan [4,5], agar [6], alginate [7], carrageenan [8], Nafion [9], TCAP [10], DDAB [11], Eastman AQ polymer [12], etc. have been used as immobilization matrices, but only a few reports have been cited in the literature concerning the use of gelatine as a matrix. Gelatine consists of different amounts of 18 amino acids, where glycine, proline and