3D Electrochemical Sensor and Microstructuration Using Aerosol Jet Printing.

Tiziano Fapanni,Sarah Tonello,Mauro Serpelloni,Emilio Sardini

doi:10.3390/s21237820

Tiziano Fapanni, Sarah Tonello + Show 2 more

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https://doi.org/10.3390/s21237820

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Abstract

Electrochemical sensors are attracting great interest for their different applications. To improve their performances, basic research focuses on two main issues: improve their metrological characteristics (e.g., repeatability, reusability and sensitivity) and investigate innovative fabrication processes. In this work, we demonstrate an innovative microstructuration technique aimed at increasing electrochemical sensor sensitivity to improve electrode active area by an innovative fabrication technique. The process is empowered by aerosol jet printing (AJP), an additive-manufacturing and non-contact printing technique that allows depositing functional inks in precise patterns such as parallel lines and grids. The 3D printed microstructures increased the active surface area by up to 130% without changing the substrate occupancy. Further, electrochemical detection of ferro/ferri-cyanide was used to evaluate the sensitivity of the electrodes. This evaluation points out a sensitivity increase of 2.3-fold on average between bare and fully microstructured devices. The increase of surface area and sensitivity are well linearly correlated as expected, verifying the fitness of our production process. The proposed microstructuration is a viable solution for many applications that requires high sensitivity, and the proposed technique, since it does not require masks or complex procedures, turns out to be flexible and applicable to infinite construction geometries.

Highlights

Electrochemical sensors are attracting increasing interest in the scientific community due to their selectivity, sensitivity, ease of use and low cost [1]
We present how we implemented and characterized a 3D microstructuration process using this technique to demonstrate a possible method to increase the overall sensitivity of an electrochemical sensor
Several examples include Randles−Sevcik (1) and Cottrell (2) equations. The former describes the peak current obtained in cyclic voltammetry (CV), an electrochemical experiment where the potential is scanned at a certain velocity

Summary

Introduction

Electrochemical sensors are attracting increasing interest in the scientific community due to their selectivity, sensitivity, ease of use and low cost [1]. In order to obtain continuous monitoring of the analytes, great attention is required in increasing sensor’s repeatability, reusability and sensitivity as well as long-term stability [6]. Specific functionalization techniques are usually employed to enhance sensitivity and selectivity [7]. Selectivity is achieved by means of different materials able to bind analytes and/or catalyze the reactions. The former is usually employed in bio-affinity sensors, where specific receptors such as antibodies, proteins or DNA are immobilized on the electrode surface and selectively bind with the analytes [8]

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