The growing market for disposable enzyme sensor strips such as for the self-monitoring of blood glucose is increasing the demand for fast response, yet sensitive and accurate sensor strips. Furthermore, the current rapid progress of micropatterning technologies for the design and fabrication of interdigitated array microelectrodes (IDAMs) is bringing IDAMs within reach at affordable cost for the disposable use. In here, we propose the employment of IDAMs, in which one of the interdigitated electrodes is set as the working electrode (WE) and the other interdigitated electrode as the counter electrode (CE), as alternate electrodes to screen-printed electrodes and gold planar electrodes for disposable enzyme sensors. Simulation studies using COMSOL Multiphysics showed, that an immediate high quasi-steady state response current depending on the concentration of reduced mediator can be achieved by applying an oxidizing potential to the WE. The interdigitated CE controls the diffusion of the mediator by a form of redox-cycling between the WE and CE and limit the diffusion layer to the immediate vicinity of the electrode. The often-disregarded CE position and CE reaction are crucial for the functionality of the application of IDAMs for amperometric enzyme sensor strips. Experimental evaluation of IDAMs with mixtures of reduced and oxidized mediator confirmed an immediate high quasi-steady state response current depending on the concentration of reduced mediator with an oxidizing potential applied to the WE, as we expected from the results of simulation. Furthermore, we demonstrate the practical applicability of IDAMs by fabricating sensor strips for glucose and for glycated albumin. These experimental results, together with the simulation studies, suggest that IDAMs will be the next platform technology for the construction of disposable enzyme sensor strips.<br/>

Controlling the mediator diffusion in disposable enzyme sensor strips by utilizing interdigitated array microelectrodes

2019 Spring National Meeting

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