Biosensor amperométrico para la medida de la galactosa compuesto por microgeles de poliacrilamida

Abstract

Galactosemia is one of the natural errors of the metabolism more frequent, its clinical representation in children not treated can be severe, sometimes mortal; its diagnostic is relatively simple and its treatment is very easy and effective. Hence, in last years new biosensors design for galactose determination based on galactose oxidase has been proposed. The aim of this work consists of the immobilization of galactose oxidase (GlOx) in polyacrylamide microparticles, using the concentrated emulsion method, and their use as biological material of a new amperometric biosensor for galactose determination. For preparing the galactose biosensors, microparticles with galactose oxidase were deposited on the surface of a platinum electrode and covered with a dialysis membrane. Microparticles were characterized by a Galai Cis-1 particle analyzer system, scanning electron microscopy, X-rays diffraction and differential scanning calorimetry. The presence of galactose oxidase decreases the transition temperature (Tg) of the polyacrylamide microgels. The influence of several experimental factors, such as crosslinking content, pH and temperature, on the biosensor response was investigated. The optimal performance of the biosensor takes place for a cross-linking of 7.0%, 40ºC and pH 7.0. The proposed immobilization system almost does not modify the enzyme activity, but seems to protect to the enzyme because an increase of the temperature range in which the enzyme is active is observed.