A Concentric Ring Electrode for a Wall‐jet Cell in a Microfluidic Device

Abstract

A concentric ring array electrode that amplifies the current signal without redox cycling has been developed for highly sensitive electrochemical detection at a single potential in a microfluidic platform. Herein, the effect of ring‐electrode width on the current and current density was examined. A ring‐array electrode with widths that decrease from the inner to the outer ring was shown to exhibit the highest sensitivity. This electrode delivered a current density that was approximately 50 % higher than that of a conventionally used disc electrode. We used numerical simulations to further optimize this type of array electrode, which led to a limit of detection for catechol of 6.2 nmol/L. This ring array electrode has great potential for use in a variety of applications because it can be used to detect irreversible targets with a simple apparatus at a single potential and requires no electrode modification to achieve high sensitivity.

Numerical Study on a Bio-Inspired Micropillar Array Electrode in a Microfluidic Device

“…The working electrode (WE) is the most crucial element, since its features are directly related to the performance of the µEDS compared to the reference electrode (RE) and the counter electrode (CE). WEs in the µEDS often have two-dimensional (2D) planar forms of bands [ 12 , 13 ], disks [ 9 , 14 ], microarrays [ 6 ] and rings [ 15 ] and are directly integrated inside a microchannel. In addition to the planar configurations, the three-dimensional (3D) micropillar array electrode (μAE) has recently been reported as an emerging technology with a large current response [ 16 , 17 , 18 , 19 ].…”

“…Numerical simulations are a common and effective approach to understanding the performance of the µEDS integrated with bμAEs. By solving the Navier–Stokes equation, convention-diffusion equation and Butler–Volmer equation [ 30 , 31 , 32 ], conventional electrodes have been widely studied, such as microbands [ 33 ] and rings [ 15 , 34 ]. However, those research objects are usually simplified geometrical or mathematical models.…”

A Numerical Study on the Electrochemical Sensing Properties of Micropillar Array Electrodes in a Microfluidic Chip

“…Three-dimensional (3D) microelectrode arrays have gained popularity in sensor development recently since they can provide a much larger surface area than conventional planar electrode and lead to higher response current [1], lower impedance [2] and limit of detection [3]. Integrating 3D microelectrode array into a microchannel can realize miniaturization [4] and portability [5] of electrochemical sensors and achieve better performance including shorter assay time [5], higher throughput [1] and efficiency [6].…”

“…Numerical simulation is an effective method to investigate the electrochemical behavior of microelectrode. Microelectrodes with different configurations including two-dimensional (2D) band [7], disk [8,9], ring [5,10] and 3D sphere [7,11], pillar [2,12] were investigated under both static and flow conditions [13,14]. In most of these researches, simplified 2D geometrical and mathematical models were used.…”