Improving sensitivity of a miniaturized label-free electrochemical biosensor using zigzag electrodes

Cardiovascular disease (CVD) is a leading cause of death among chronic diseases worldwide. Therefore, it is important to be able to detect CVD biomarkers early so that patients can be diagnosed properly and begin treatment as soon as possible. To detect biomarkers more conveniently, point-of-care (PoC) biosensors, which are easy to use and are of low cost, are becoming even more necessary. This paper focuses on developing a label-free electrochemical biosensor with high sensitivity for PoC applications to detect CVD biomarkers such as S100 beta proteins and C-reactive proteins (CRP). To meet the requirements of a PoC application and to improve the measurement sensitivity for detection purposes, a three-electrode configuration was miniaturized and fitted onto a biochip. Computer simulation of an electrolyte current density was used to investigate several potential effective possibilities. It was found that an electrolyte current density at an edge tip structure near the working electrode (WE) and counter electrode (CE) was higher than at other locations. A zigzag structure was then designed at the edge near the WE and CE positions. With this design, we can obtain a higher total electrolyte current. This newly-designed biochip was then used to measure the electrochemical feature. It was found that the measurement efficiency was also improved using this newly designed biochip.