Immobilization of Peroxidase onto Magnetite Modified Polyaniline

Eduardo Fernandes Barbosa,Kátia Flávia Fernandes,Pedro Antonio García-Ruíz,Samantha Salomão Caramori,Fernando Javier Molina,Flavio Marques Lopes

doi:10.1100/2012/716374

Abstract

The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25%) obtained for PANIG with an efficiency of 100% (active protein). The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity.

Highlights

In the last decade, several works have been conducted with polyaniline (PANI) as the matrix for immobilization of horseradish peroxidase (HRP) and its application in the development of biosensors based on the conductive properties of the polymer support [1,2,3,4,5,6]
The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde
FT-IR analysis showed the characteristic bands of polyaniline and those related to modifications introduced by treatment with glutaraldehyde and magnetization (Table 1)

Summary

Introduction

Several works have been conducted with polyaniline (PANI) as the matrix for immobilization of horseradish peroxidase (HRP) and its application in the development of biosensors based on the conductive properties of the polymer support [1,2,3,4,5,6]. In its chemically synthesized form, PANI has been studied as support for immobilization of several other enzymes [7,8,9,10,11,12,13,14] Our experience with this support for immobilization of HRP include the relationship between the oxidation state of PANI and the amount of protein retained [7, 8], the acquired stability at extremes of pH, during long-time storage, under organic environment exposition, and during repeated use [8]. Considering PANI as support for enzyme immobilization and its use for the development of a batch reactor, the separation from reaction medium requires additional procedures such as centrifugation, filtration, or decantation, which are time and energy consuming Attempts to overcome these problems include synthesis of composites of PANI, such as polyethylene terephthalate-PANI [16] and PVA-PANI [17] which can be manually removed from the reaction medium. The capacity of retention was drastically reduced as a consequence of reduction in the area for immobilization, similar to what occurs with electrochemically synthesized PANI

Methods

Results

Conclusion