Optimum Design of the Electrode Structure and Parameters in Electric Cell-substrate Impedance Sensing and Electrochemical Impedance Spectroscopy

Recently, ECIS (Electronic Cell-substrate Impedance Sensing) has emerged as a popular method for detecting cancer cells. The conventional technique involves fabricating electrodes using expensive photolithography on glass. However, it faces limitations in simultaneously creating numerous electrodes on a single substrate due to the restricted effective radius of ultraviolet (UV) exposure. To address these challenges, we conducted a study to replace glass photolithography with PCB (Printed Circuit Board) technology and explore the design and materials used in electrode construction. Certain materials, including a fiberglass (FR4) substrate and solder mask layer, were toxic to cells and tissues in our experiments. However, this issue was mitigated by employing epoxy-SU8 resin layers, ensuring biocompatibility and making the board suitable for use in biological research and pathology laboratories. The adoption of the PCB approach brings significant cost benefits, as the fabrication of twelve electrodes via photolithography is nine times more expensive than using the PCB method. Moreover, the versatility of this technology allows for the utilization of various biocompatible materials and different electrode patterns. This offers ample opportunities for application in diverse fields.