High temperature stabilisation of immobilised glucose oxidase: potential applications in biosensors

A novel system for the immobilisation of glucose oxidase onto controlled pore glass (CPG) beads using an enzyme-polyelectrolyte complex to increase the thermal and operational stability is discussed. Native glucose oxidase has been shown to be fairly unstable in solution and this can cause problems in reusable biosensors in conditions where multiple analyses are required over variable time scales, e.g. monitoring fermentations. This method of stabilisation allows operational stability over a wide temperature range and for extended periods of time without adverse effect to the activity of the enzyme. In this system the enzyme-polyelectrolyte complex is formed first in solution then covalently immobilised to alkylamine CPG beads using glutaraldehyde activation. Solutions of buffered sorbose or trehalose can be used to further enhance stability. The immobilised enzyme displayed high operational stability when tested at elevated temperatures up to 100 degrees C for time periods up to 15 min. The use of such a system may be extended to produce glucose sensors having high temperature operational stability characteristics in analytical systems. (C) 1997 Elsevier Science S.A.