The effect of electrical distribution on agar plate using ring electrodes

The experimental set up for studying the effects of electric current on cell activities in vitro that always be performed is based on straight parallel electrodes which can generate a specific magnitude of current density on the cultured cells. This depends on input voltage and the gap between the electrodes. With this method, lots of set-ups for trial & error are required to find the threshold of any effects. This study suggested a novel technique which used 2 ring electrodes (inner electrode and outer electrode with 5.50 and 40.65 mm radius respectively) to spread out the current radially and cause the current density near the inner electrode to be more intense than the outer electrode. A simple equation was provided to approximate the current density at any point on the surface of the agar between the electrodes. This equation was verified by comparing the calculated result to the result from the finite element method and to the result from testing on a real blood agar. By comparing to the result from the finite element method, there is a mean error of the current density and voltage difference for 10-35 mm and 8-30 mm radius about 1.7341 ± 0.9868% and 2.9563 ± 1.8867% respectively. By comparing to the result from testing on a real blood agar, there is a mean error of the voltage difference for 10-20 mm radius about 3.78±1.70%. With this new technique, the researchers just locate the area on the petri dish that has cellular changes and calculate the magnitude of the current density that is linked to the results by the provided equation. This method can waste fewer set-ups for trial & error and shorten the length of the study.