Bioelectrocatalytic endpoint assays based on steady-state diffusion current at microelectrode array

Abstract

Highly reproducible bioelectrocatalytic endpoint assays are described. The method is based on a complete redox conversion of a substrate to a redox mediator with a corresponding redox enzyme and an amperometric detection of the reduced mediator on a diffusionally independent microelectrode array. The current reaches a steady state within a few seconds and is proportional to the number of the integrated microelectrodes. The method has successfully been applied to histamine detection at micro-molar level and glucose detection at milli-molar level.

Diffusion-controlled Detection of Glucose with Microelectrodes in Mediated Bioelectrocatalytic Oxidation

“…This is a typical endpoint assay as a highly reproducible amperometric detection method with microelectrodes in mediated bioelectrocatalysis, where the current is controlled by the diffusion of reduced mediator. 13 On the other hand, even when cglc > cBQ, the ilim increased linearly with cglc. The steady-state current at microdisk-electrodes in homogeneous mediated enzyme reaction has been numerically calculated.…”

Development Perspective of Bioelectrocatalysis-Based Biosensors

“…Although microdisk electrodes provide clear steady-state current, the current is quite small. In order to increase the current, microdisk electrode array without overlapping of the diffusional concentration gradients (scattered microdisk electrode array) is one of the solutions [ 38 , 121 , 122 , 123 ]. However, the fabrication of such a scattered microdisk electrode array is a technically challenging issue.…”

“…If one can use biosensors without calibration, it is easy to monitor the concentration of target analytes. In this sense, microelectrode detection was introduced to develop amperometric biosensors [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. Nonlinear diffusion of the substrate at microelectrodes causes diffusion-controlled steady-state currents.…”

Fabrication and Characterization of Ultrathin-ring Electrodes for Pseudo-steady-state Amperometric Detection

“…[12][13][14] However, the fabrication of the coarsely arranged microdisc electrode array is technically difficult and is not suitable for mass production for practical applications. Another idea to obtain a large steady-state signal is to use a microband electrode.…”