## 3 Results
### The Influence of Non-Conductive Materials on Charge Generation in Water Flow
#### 3.2.1 The Influence of Polypropylene Tube on Charge Generation in the Flow-based System  
The generation of charge in the system for AFM-based fishing and its accumulation in the cell upon pumping of water through the injector with a peristaltic pump at T = 35 \({}^{\circ}\)C in the presence of an empty polypropylene tube near the injector nozzle was monitored. At the distance \(l\) = 4 mm, the trajectory of water drops falling from the injector nozzle into the cell bended from the vertical direction towards the polypropylene tube, and the drops adhered to the tube wall. For this reason, it was impossible to measure the charge accumulation in the cell in these conditions. Figure 7 displays averaged time dependencies of charge accumulation in the measuring cell in the absence of the polypropylene tube, as the variation between the \(\Delta q(t)\) observed within the corresponding series of three experiments was insignificant. The averaged dependencies for the case when the tube was placed at a distance \(l\) = 1 cm from the injector nozzle are also presented in this figure. An increase in the rate of charge accumulation is observed, when an empty polypropylene tube was placed near the injector nozzle--as compared to the case without the tube. The charge accumulation rate within the series of three repeated experiments without the polypropylene tube was 26 to 28 nC in 7 min, the average value was (27 \(\pm\) 1) nC in 7 min. In the presence of the polypropylene tube, an increased level of charge accumulation (77 to 86 nC) was observed within the respective series of three repeated experiments, with an average value of (82 \(\pm\) 4) nC in 7 min, and the time dependence was linear. Table 1 (see Discussion section) lists the data obtained when a polypropylene tube was placed at a distance \(l\) = 1 cm from the injector nozzle. As seen from Table 1, the relative change in the value of charge accumulated in the cell in 7 min in the presence of an empty polypropylene tube makes up 204%. The charge on an empty polypropylene tube was measured. The measured charge on an empty polypropylene tube was \(-\)24 nC. Polyppropylene Tube Filled with Water, Protein Solution or Ethanol  
The influence of a polypropylene tube filled with either water, protein solution (\(10^{-4}\) M and \(10^{-15}\) M BSA) or 96% ethyl alcohol (which are used as model solutions in nanobiosensors) was measured. Water-Filled Polypropylene Tube  
The generation of charge in the system for AFM-based fishing and its accumulation in the cell upon pumping of water through the injector with a peristaltic pump in the presence of a water-filled polypropylene tube, placed at a distance \(l\) = 1 cm from the injector nozzle, was monitored. Figure 8 displays averaged time dependencies of charge accumulation in the measuring cell obtained when a polypropylene tube was placed at a distance \(l\) = 1 cm from the injector nozzle. As seen from Figures 7 and 8, an increase in the rate of charge accumulation is observed when a water-filled polypropylene tube is placed near the injector nozzle--as compared to the case without the tube. At the same time, this increase is less pronounced than in the case with an empty polypropylene tube. The charge accumulation rate within the series of repeated experiments in the absence of the water-filled polypropylene tube was 26 to 28 nC in 7 min, the average value was (27 \(\pm\) 1) nC in 7 min. In the presence of the water-filled polypropylene tube (placed at a distance \(l\) = 1 cm from the injector nozzle), an increased level of charge accumulation (35 to 36 nC) was observed within the respective experimental series, with an average value of (36 \(\pm\) 1) nC in 7 min, and the time dependence was linear. Table 1 (see Discussion section) lists relative data on the charge generation obtained when the water-filled polypropylene tube was placed at a distance \(l\) = 1 cm from the injector nozzle.