Simulating electrical properties of interdigitated electrode designs for impedance-based biosensing applications

In this paper, we describe a point-of-care biosensor design. The uniqueness of our design is in its capability for detecting a wide variety of target biomolecules and the simplicity of nanoparticle enhanced electrical detection. The electrical properties of interdigitated electrodes and the mechanism for gold nanoparticle-enhanced impedance-based biosensor systems based on these electrodes were simulated using COMSOL Multiphysics software. Understanding these properties and how they can be affected by the design of the sensor, environment during detection, and target biomolecules is vital in designing effective biosensor devices. Simulations were used to show electrical screening for interdigitated electrodes in a salt solution as well as the electric field between individual digits of electrodes. Using these simulations, it was observed that gold nanoparticles bound closely to interdigitated electrodes can lower the electric field magnitude between the digits of the electrode.

I. Introduction

Biosensor devices hold great potential for various applications in detecting the growth of cells and bacteria [1], [2], detecting toxins [3], and detecting and monitoring disease progression [4], [5]. Different detection designs based on optical, mechanical and electrochemical methods have been proposed [6]–[8]. These individual designs each have their own advantages and disadvantages. Electrical and electrochemical detection techniques are particularly well suited for quick and simple detection [8].