Improvements in the stability characteristics of biosensors using protein-polyelectrolyte complexes

The formation of protein-polyelectrolyte complexes has been directly demonstrated for several enzymes in solution including alcohol oxidase, horseradish peroxidase, lactate oxidase and glucose oxidase using agarose gel electrophoresis. The combination of such complexes with polyhydroxyl compounds has been found to significantly enhance the shelf-life of biosensors when stored in a dehydrated form, examples of lactate and malate biosensors are given. There is evidence from enzyme solution and immobilisation experiments that the protein-polyelectrolyte complexes also have the ability to improve the operational stability of the enzyme activity during catalysis. This ability may be used to produce biosensors having extended working lifetimes for use in analytical devices.