**5. The final product: a tool for the environment monitoring**

The final interdigitated structure comprises 98 horizontal metallic traces, which are starting from the central pillar for each electrode, detail in **Figure 12**.

After the enzyme entrapping, the integrated biosensor was tested by capacitance-voltage (C-V) analysis. The capacitance-voltage experimental curve is measured for the final product, after the enzyme entrapping, but in the absence of pesticide in measured solution.

The capacitance ranges from 45 nF up to a minimum of 7 nF, in agreement with p-NOI electrode structures with 8μm width and 10 μm gap space. The shape of the C-V curve

**Figure 12.** Detail of electrodes on the final product.

proves that our capacitive biosensor works as a p-NOI capacitor, with enzyme on nanoporous Si material on Si substrate. The voltage ranging from negative values toward positive values brings the capacitor from the accumulation regime through the depletion regime the middle decreasing part of the curves—toward the inversion regime. The C-V curve is almost reproducible that indicates an adequate enzyme entrapping onto the silicon surface occurred.
