Proposed model for shelf-life prediction of stabilised commercial enzyme-based systems and biosensors

The ability to use model systems to predict the shelf-life of biological products is an extremely important area for enzyme manufacturers and the diagnostic industry in particular. Biosensor devices where the biological recognition is carried out by enzymes, antibodies or some other relatively unstable material are also subject to deactivation and therefore have a finite lifetime on storage. This shelf stability is obviously of the highest importance to biosensor manufacturers, however the experimental protocols used to predict the shelf-life of these devices are generally well guarded company secrets and little attempt has been made to standardise such methods. This paper presents a generic model system that is able to estimate shelf-stability to a high degree for first order enzyme deactivations and may be used as a rough guide for screening enzyme based systems, including biosensors where the order and mechanism of deactivation is unclear. Dehydrated glucose oxidase in unstabilised and stabilised forms, solution stabilised antibody-enzyme conjugate and glucose oxidase biosensors are presented as experimental examples. (C) 1999 Elsevier Science B.V. All rights reserved.