Determination of stability characteristics for electrochemical biosensors via thermally accelerated ageing.

Biosensors are devices that are prone to ageing; this phenomenon can be characterized as a decrease in signal over time. Biosensor stability is of a crucial importance for commercial success and as biosensors are presently being applied to an increasing and variety of applications. Stability characteristics related to shelf life, reusability and/or continuous use stability are often poorly investigated or unreported in literature, yet are important factors. Instability or ageing can be accelerated at an elevated temperature; Arrhenius (exponential) and linear models were investigated in order to propose a novel method for rapid ageing characteristics determination. Linear correlation proved more suitable with higher coefficients of determination than exponential correlation. Degradation rate is linearly dependent on temperature and by utilizing the proposed models, long term shelf life of a biosensor can be determined in 4 days and continuous use stability in less than 24h. Reusability studies are found to correlate poorly due to the unpredictable nature of biosensor handling. Basic constructed screen printed electrode glucose oxidase biosensors were used as a model biosensor in order to propose models for shelf life, reusability and continuous use stability.