Modelling Impedance for 3D Impedimetric Biosensor

There is a growing need for new biosensing technologies that are more rapid and convenient to use for onsite sensing. Impedance-based electrochemical sensor is a promising candidate due to simplicity of its sensing mechanism. However, like other emerging biosensors, specificity, sensitivity, and reliability are major obstacles that limit their use in real-life applications. Electrode geometry and 3D shape design optimization have been popular research directions for improved sensor performance. The aim of this study is to develop a finite element modelling approach that allows calculation of electrode impedance for different electrode shapes under standard biological test medium. In addition, a method for comparing sensor sensitivity is also developed using bacterial target as case study. Impedance simulations were performed for different electrode shapes, namely flat, ridge, and trough. The effects of target binding on solution conductivity and diffusion were simulated. It was found trough shaped electrode showed the greatest change in diffusion impedance upon target recognition. However, different shapes gave maximum change in solution impedance depending on the position of bound target.