Design of an Alternating Current Field Controller for Electrodes Exposed to Saline Solutions

The production of giant unilamellar vesicles (GUV) has been the subject of many studies due to its simplicity and to mimic essential complex functions of biological membranes. The precise control of the medium temperature and the electric field amplitude in saline solutions is crucial for the formation of GUV to be used in the analysis training protocols for biomedical applications. Herein, we propose two automatic temperature control methods and stability of the electric field amplitude in the saline solution. The control system is based on a microcontroller that uses pulse width modulation to control the actuation devices. Over time, the field amplitude stability was assessed through an applied electric field with a frequency of 500 Hz and a voltage amplitude of 600 mVrms. Two algorithms for controlling the field amplitude were analyzed: bang-bang and proportional-integral-derivative (PID). Their performance was evaluated in saline solutions kept at room temperature and 60 °C. The mean values of the field in the absence of control, with bang-bang control and PID control, showed differences compared to the initial value, 17%, 1%, and 0.3%, respectively. Based on findings, the PID protocol proved to be the most effective in maintaining field values over time.