Biocompatible and flexible paper-based metal electrode for potentiometric wearable wireless biosensing

Abstract

A paper-based electrode is a very attractive component for a disposable, nontoxic, and flexible biosensor. In particular, wearable biosensors, which have recently been attracting interest, not only require these characteristics of paper-based electrodes but must also be able to detect various ions and biomolecules in biological fluids. In this paper, we demonstrate the detection ability of paper-based metal electrodes for wearable biosensors as part of a wireless potentiometric measurement system, focusing on the detection of pH and sodium ions. The paperbased metal electrodes were obtained by simply coating a silicone-rubber-coated paper sheet with a Au (/Cr) thin film by sputtering then modifying it with different functional membranes such as an oxide membrane (Ta 2 O 5) and a fluoropolysilicone (FPS)-based Na +-sensitive membrane, corresponding to the targeted ions. Satisfactory and stable detection sensitivities of the modified paper-based Au electrodes were obtained over several weeks even when they were bent to a radius of curvature in the range of 6.5 to 25 mm, assuming use in a flexible body patch biosensor. Moreover, the Na + concentration in a sweat sample was evaluated using the paperbased Au electrode with the FPS-based Na +-sensitive membrane in a wireless and real-time manner while the electrode was bent. Thus, owing to their complex mesh structure, flexible paper sheets should be suitable for use as potentiometric electrodes for wearable wireless biosensors.

Paper-based wearable electronics

“…Such biosensing applications can be exemplified by modifying paper electrodes with ion-selective membranes for potentiometric ion sensors. Various ion-selective electrodes are adopted for the detections of Cd 2+ , Ag + , K + , NH 4 + , Cl À , and Na + (Hu et al, 2016;Mensah et al, 2014;Novell et al, 2012;Sakata et al, 2020). Given the intrinsic high porosity of cellulose paper substrate, these devices usually possess enhanced active surface area and therefore exhibit higher sensitivity.…”

Graphene Oxide Nanoparticles Modified Paper Electrode as a Biosensing Platform for Detection of the htrA Gene of O. tsutsugamushi

“…Low-cost disposable materials, such as paper-based electrodes, have gained considerable attention for the construction of electrochemical sensors due to their ability to work with low sample volume, low cost, and higher flexibility [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. These electrodes show excellent sensitivity, LOD, and stability in the detection of the targeted analyte using different samples [ 12 , 13 , 14 , 15 , 16 ].…”

“…The performance of such electrodes in terms of sensitivity and stability can be polished using different nanomaterial and their composites. The paper electrodes modified using carbon-based nanomaterials have gained substantial attention due to the ease of coating and printing to improve the performance of the biosensor [ 11 ]. The use of a graphene oxide nanomaterial for electrochemical biosensing has gained provenance of excellent performance in electrocatalysis and lower resistance to charge transfer ratio [ 17 ].…”

Ultrasensitive and Low-Cost Paper-Based Graphene Oxide Nanobiosensor for Monitoring Water-Borne Bacterial Contamination

“…Also, it possesses notable features such as biocompatibility, porosity, eco-friendliness, and low fabrication cost. 21,24,25 All of these attributes of paper can be deployed to fabricate paper-based biosensors with high precision and accuracy. The paper-based electrochemical biosensing technique was first reported by Dungchai et al using screen-printed carbon ink to determine the glucose, lactate, and uric acid in biological samples.…”