First-Generation Biosensors

The major drawbacks of the first-generation biosensor approach are the following (i) if the O2 concentration is monitored, it is challenging to maintain a reasonable reproducibility due to varying O2 concentrations within the sample and (ii) working electrode potentials for either the oxidation of H2O2 or the reduction of O2 are not optimal because these potentials are prone to the impact of interferences present in biological samples, such as ascorbic acid or dopamine. 

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A. Karaykin, O. Gitelmacher, and E. Karaykina, Prussian blue-based first-generation biosensor. A sensitive amperometric electrode for glucose. Anal. Chem. 67, 2419—2423 (1995). 

A.A. Karyakin, E.A. Kotel nikova, L.V. Lukachova, E.E. Karyakina, and J. Wang, Optimal environment for glucose oxidase in perfluorosulfonated ionomer membranes improvement of first-generation biosensors. Anal. Chem. 74, 1597—1603 (2002). 

Figure 1.3 Schematic representation of the architecture of a first-generation biosensor.

Even with a simple first generation biosensor, working in amperometric mode at a fixed detection potential of +0.7 V (high enough to directly oxidize H2O2 at the electrode surface), it is possible to achieve a linearity between 1 and 9 x 10 M (R = 0.9997) with a sensitivity of 1.11 pAmM (rsd% = 0.97%) and a limit of detection between 2.5 x 10 M (calculated as S/N = 3). Short-term stability was excellent as shown in Figure 13.19. Longterm stability results in a decrease of 34% after one month of continuous use. 

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