A numerical study of geometric and flow factors influencing the performance of micropillar electrode biosensors

Micropillar array electrodes have piqued the interest of researchers as a promising new technology. With their enhanced surface area characteristics, such electrodes result in improved microfluidic biosensor performance. While the efficiency of biosensors has been found to diminish due to certain fundamental phenomena, current knowledge of such underlying phenomena within the micropillar electrode array context, is rather limited. Consequently, further study is required to reduce them, so as to understand and evaluate their effects on biosensor performance. This work seeks to address this gap in the literature. In particular, we seek to highlight phenomenological factors apart from diffusion boundary layer effects. The study is done by employing a finite-element based software, COMSOL Multiphysics. This is done to numerically investigate the effects of geometry and flow conditions on micropillar electrode biosensor performance. Two configurations—staggered and inline—are analyzed. The results demonstrate that due to enhanced mixing induced within the flow, the staggered arrangement has a 25% improvement in response time compared to the inline arrangement. Additional parametric tests also indicate that relative factors due to geometry and flow play a significant role in controlling concentration rates. Overall, it is shown that biosensor response times are most effectively controlled when the ratio of the flow’s inertia and viscous forces is less than 0.1.