Enzyme Electrodes with Enzyme Immobilised by Solgel Technique

Abstract

In this work, the preliminary results of immobilisation of enzymes in silica gel on oxygen electrode are reported. As the model enzyme glucose oxidase was used. The influence of the composition of the casting solution (gel precursor, pH of the enzyme solution, sol-water ratio) on the electrode response was investigated. In addition, the addition of -aminopropyltrieethoxy silane to the casting solution was checked. The best electrode with stable signal was obtained when the formed gel was not very rigid (buffer, pH 6 or 7 and high water-sol ratio). For the optimal composition of the casting solution, some properties of the glucose electrode were investigated (stability, influence of pH and temperature). The method of sol-gel entrapment was also used to obtain the electrodes for disaccharides by co-immobilisation of invertase, lactase and maltase with glucose oxidase. In addition, other oxidases were immobilised with this method. For electrode with immobilised tyrosinase some additional measurements were done like influence of pH, temperature, addition of organic solvents, NaCl and SDS. Also, the broad spectrum of different substrates of this enzyme was tested.