Electrochemical Performance of Micropillar Array Electrodes in Microflows.

Bo Liu,Bin Ran,Minbo Lan,Chuanwen Lv,Chaozhan Chen,Huaying Chen,Yonggang Zhu

doi:10.3390/mi11090858

Abstract

The microchip-based electrochemical detection system (μEDS) has attracted plenty of research attention due to its merits including the capability in high-density integration, high sensitivity, fast analysis time, and reduced reagent consumption. The miniaturized working electrode is usually regarded as the core component of the μEDS, since its characteristic directly determines the performance of the whole system. Compared with the microelectrodes with conventional shapes such as the band, ring and disk, the three-dimensional (3D) micropillar array electrode (μAE) has demonstrated significant potential in improving the current response and decreasing the limits of detection due to its much larger reaction area. In this study, the numerical simulation method was used to investigate the performance of the μEDS, and both the geometrical and hydrodynamic parameters, including the micropillars shape, height, arrangement form and the flow rate of the reactant solution, were taken into consideration. The tail effect in μAEs was also quantitatively analyzed based on a pre-defined parameter of the current density ratio. In addition, a PDMS-based 3D μAE was fabricated and integrated into the microchannel for the electrochemical detection. The experiments of cyclic voltammetry (CV) and chronoamperometry (CA) were conducted, and a good agreement was found between the experimental and simulation results. This study would be instructive for the configuration and parameters design of the μEDS, and the presented method can be adopted to analyze and optimize the performance of nanochip-based electrochemical detection system (nEDS).

Highlights

A microchip-based electrochemical detection system, which is developed on the basis of electrochemical methods and microfluidic techniques, has demonstrated satisfactory benefits including automation, compatibility, fast analysis time, reduced reagent consumption, high sensitivity and strong specificity [1,2,3,4], and has been widely used for various on-site real-time applications [5] as well as point-of-care diagnosis [6,7,8].Electrochemical detection (ED) is carried out based on the redox reaction of underivatized electroactive species occurring at the electrode surface [9]
The miniaturized working electrode is usually regarded as a core component, of which the characteristic is directly related to the performance of the whole μEDS system
Micropillars of the μAE are all located in a specified area (1.5 × 2.5 mm2), the number of micropillars and the total surface area of μAE are confined by the spacing between two adjacent micropillars

Summary

Introduction

A microchip-based electrochemical detection system (μEDS), which is developed on the basis of electrochemical methods and microfluidic techniques, has demonstrated satisfactory benefits including automation, compatibility, fast analysis time, reduced reagent consumption, high sensitivity and strong specificity [1,2,3,4], and has been widely used for various on-site real-time applications [5] as well as point-of-care diagnosis [6,7,8].Electrochemical detection (ED) is carried out based on the redox reaction of underivatized electroactive species occurring at the electrode surface [9]. Most of the microelectrodes were designed into a simple two-dimensional (2D) planar band [10], disk [11,12], ring [13] or slightly more complicated shapes such as hemisphere [14], cylinder [15] and ring [16] Besides these conventional configurations, the three-dimensional (3D) microelectrodes array (μAE) has received comprehensive attention since it can provide a much larger surface area and lead to higher response current [17], lower impedance [18] and limit of detection [19]. These researches were only limited to improve the electrochemical performance of the μAE through optimizing one or several of these parameters, of which the influences on the current responses of the μAE didn’t get studied systematically

Objectives

Methods

Results

Conclusion