Pencil It in: Exploring the Feasibility of Hand-Drawn Pencil Electrochemical Sensors and Their Direct Comparison to Screen-Printed Electrodes.

Elena Bernalte,Dale Brownson,Christopher Foster,Graham Smith,Craig Banks,Morgane Mosna

doi:10.3390/bios6030045

Elena Bernalte, Dale Brownson + Show 4 more

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https://doi.org/10.3390/bios6030045

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Abstract

We explore the fabrication, physicochemical characterisation (SEM, Raman, EDX and XPS) and electrochemical application of hand-drawn pencil electrodes (PDEs) upon an ultra-flexible polyester substrate; investigating the number of draws (used for their fabrication), the pencil grade utilised (HB to 9B) and the electrochemical properties of an array of batches (i.e, pencil boxes). Electrochemical characterisation of the PDEs, using different batches of HB grade pencils, is undertaken using several inner- and outer-sphere redox probes and is critically compared to screen-printed electrodes (SPEs). Proof-of-concept is demonstrated for the electrochemical sensing of dopamine and acetaminophen using PDEs, which are found to exhibit competitive limits of detection (3σ) upon comparison to SPEs. Nonetheless, it is important to note that a clear lack of reproducibility was demonstrated when utilising these PDEs fabricated using the HB pencils from different batches. We also explore the suitability and feasibility of a pencil-drawn reference electrode compared to screen-printed alternatives, to see if one can draw the entire sensing platform. This article reports a critical assessment of these PDEs against that of its screen-printed competitors, questioning the overall feasibility of PDEs’ implementation as a sensing platform.

Highlights

IntroductionThere is constant focus on the creation of low cost and efficient analytical techniques
Among academia and industry, there is constant focus on the creation of low cost and efficient analytical techniques
These pencil electrodes (PDEs) are evaluated in terms of pencil “batch” reproducibility and the overall feasibility of these electrode systems in terms of electrochemical sensing in comparison to commonly utilised screen-printed electrodes (SPEs), considering aspects such as the pencil grade used for the fabrication, analytical sensitivity and other surface features

Summary

Introduction

There is constant focus on the creation of low cost and efficient analytical techniques. The development of portable, low cost, and miniaturised analytical devices has promoted a true scientific revolution over the last decades [1]. The utilisation of “popular” carbon-based materials offers exciting possibilities within such electrochemical devices in general, due to their cost-effective production, that can exhibit similar or enhanced performance to that of the traditional noble metal based alternatives. An extremely attractive and effective technique to incorporate these electroactive materials is via the utilisation of screen-printing technology [2]. These screen-printed sensors have transformed the field due to their capability to bridge the gap between laboratory experiments with in-field implementation [3,4,5,6,7]

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