Tumor-treating fields (TTFields) are alternating electrical fields of intermediate frequency and low intensity that can slow or inhibit
tumor growth by disrupting mitosis division of cancerous cells through
cell cycle proteins. In this work, for the first time, an in-house fabricated cyclo-
olefin polymer made microfluidic
bioreactors are integrated with Cr/Au interdigitated
electrodes to test TTFields on yeast cells with fluorescent
protein:Nop56 gene. A small gap between
electrodes (50 μm) allows small voltages (<150 mV) to be applied on the cells; hence, uninsulated
gold electrodes are used in the non-faradaic region without causing any electrochemical reaction at the
electrode-medium interface. Electrochemical modeling as well as impedance characterization and analysis of the
electrodes are done using four different cell nutrient media. The experiments with yeast cells are done with 150 mV, 150 kHz and 30 mV, 200 kHz sinusoidal signals to generate electrical field magnitudes of 6.58 V/cm and 1.33 V/cm, respectively. In the high electrical field experiment, the cells go through electroporation. In the experiment with the low electrical field magnitude for TTFields, the cells have prolonged mitosis from typical 80-90 min to 200-300 min. Our results confirm the validity of the electrochemical model and the importance of applying a correct magnitude of the electrical field. Compared to the so far reported alternatives with insulated
electrodes, the here developed thermoplastic microfluidic
bioreactors with uninsulated
electrodes provide a new, versatile, and durable platform for in vitro cell studies toward the improvement of anti-
cancer therapies including personalized treatment.