3.1. Optimization of AG/PyOx bi-enzymatic biosensor
3.1.1. Enzyme loading
As the magnitude of the sensor signal is related to the amount of biological material in the bioactive layer, the dependence of signalamplitude on the activities of immobilized enzymes was studied. The effect of PyOx activity on the amperometric signal was initially tested in the range of 0.3 and 0.9 U while AG activity was fixed on 9.0 U.
Then, the effect of AG activity was investigated in the range of 6.0 and 12.0 U (PyOx activity was kept constant at 0.6 U). Fig. 1 shows the effect of PyOx (A) and AG (B) activities on the response in phosphate buffer (pH 6.0, 50 mM) and at 35 °C. For further studies, 0.6 U and 9.0 U of PyOx and AG activities were chosen as the optimum amount.