Nano-Functionalized Electrochemical Sensors by Aerosol Jet Printing

In the latest years, hydrogen peroxide quantification gained a growing interest in many fields both in industry and in the clinical environment. Among the different available methods, electrochemical transducers are of particular interest thanks to their ease of fabrication, convenient integration with microfluidics and electronics and their time and cost-effectiveness. Despite these advantages, electrochemical transducers are affected by many metrological issues. In this work, the novel technique of Aerosol jet printing (AJP) is exploited to fabricate fully printed nanostructured electrochemical sensors for hydrogen peroxide detection. Two different carbon-based printable nanostructures, carbon nanotubes (CNTs) and graphene, are employed to conveniently modify with the same technique electrodes' surfaces. The performances of the proposed design, production process and the different functionalization are explored and discussed. After a preliminary evaluation of the electrochemical characteristics of the printed devices, tests in hydrogen peroxide are carried on. Both materials present a limit of detections (LODs) and sensitivity comparable with the ones obtained in the literature, even though CNT better performs than graphene in terms of sensitivity (20 versus 2.8 $\mu \text{A}$ mM−2). The latter presents however a signal-to-noise ratio (SNR) of 51.2 dB that outperforms the one of CNT (26.5 dB) and thus it has a better resistance against noise. Overall, both the evaluated nanostructures appear suitable to improve the metrological characteristics of printed electrochemical sensors and ease their spreading as environmental control devices, and diagnostic tools and assess quality in the industrial environment.