## 1 Introduction
In this way, in Reference [12], the impact of the external electric potential of a closed metal ring on the generation of charge that occurs upon injection of a solution through this ring (which is not in contact with the liquid) is discussed. At the same time, the influence of materials of chips and communications on charge generation that are not in contact with the solution on the generation of charge in the solution flowing through the injector of the AFM-based fishing system is virtually not discussed in the literature. Also, it is known that the presence of macromolecules at low concentrations (including femtomolar ones) can influence the physicochemical properties of water (particularly, electrical conductivity, pH, surface tension, [13; 14]. In the literature, it is discussed that these effects can be connected with the transitions between ortho- and para-states of water owing to pumping of mixed quantum states of ortho-/para-H\({}_{2}\)O with natural and anthropogenic electromagnetic radiation (at which analytical biochemical measurements are usually carried out) [15]. In this connection, it is interesting to study not only the influence of the presence of proteins at low concentrations on charge generation of the AFM-based fishing system, but also the influence of external electromagnetic fields. In systems for AFM-based fishing, AFM chips fabricated from mica or graphite are commonly employed. Communications fabricated from polymer materials (particularly polypropylene) are also often used in nanob biosensors. For this reason, in our present work, the influence of materials of chips and communications on charge generation in a biosensor based on a system for AFM-based fishing in its flow section (described in Reference [6]) was studied. Stimulating influence of AFM chips, fabricated from mica and graphite, on charge generation in the injector section of a system for AFM-based fishing was demonstrated. The effect of an increase in the efficiency of charge generation in the flow section of nanob biosensors can well be influenced by polymer materials (particularly, those used in fluidic communications). At that, this efficiency depends on the completeness of filling of these communications with analyzed aqueous medium (water and/or aqueous protein solutions) used throughout the operation of nanobiosensors. The possibility of influence of highly dilute protein solutions (with concentrations in the range of 10\({}^{-15}\) M, what is the range of operation of highly sensitive biosensors) on the stimulation of charge generation in polymeric injector of flow-based biosensor systems has been noted. The influence of external low-frequency (50 Hz) AC electric field, applied to the injector of the system for AFM-based fishing, has also been studied. Similar to References [10; 11; 16], this field has been induced by negative AC voltage applied to electrodes, between which the injector was located. The temperature of T = 35 \({}^{\circ}\)C was selected due to the following considerations. Firstly, this temperature is lower than the temperature point of phase transition related to heat capacity [9]; secondly, this temperature is within the range of physiological temperatures of the human body, and this is the temperature of operation of biosensors upon studying biochemical processes in the human body in near-native conditions. These effects should be taken into account in the development of highly sensitive systems, whose operation is influenced by the charge state of analyzed solution.