A Disposable Planar Paper‐Based Potentiometric Ion‐Sensing Platform

Abstract

Ion-selective electrodes (ISEs) are widely used tools for fast and accurate ion sensing. Herein their design is simplified by embedding a potentiometric cell into paper, complete with an ISE, a reference electrode, and a paper-based microfluidic sample zone that offer the full function of a conventional ISE setup. The disposable planar paper-based ion-sensing platform is suitable for low-cost point-of-care and in-field testing applications. The design is symmetrical and each interfacial potential within the cell is well defined and reproducible, so that the response of the device can be theoretically predicted. For a demonstration of clinical applications, paper-based Cl(-) and K(+) sensors are fabricated with highly reproducible and linear responses towards different concentrations of analyte ions in aqueous and biological samples. The single-use devices can be fabricated by a scalable method, do not need any pretreatment prior to use, and only require a sample volume of 20 μL.

Polypyrrole Nanoparticles Based Disposable Potentiometric Sensors

“…The conducting nanoparticle suspension, either nanoPPy(TSH) or nanoPPy(NO 3 ) were used to prepare the conducting paper, Figure . As it can be seen in Figure the conducting paper obtained was black, similarly as other conducting papers described earlier by other groups using e. g. CNTs to render conductivity of the paper support . Under conditions of TEM it is clearly seen that the paper structure is fully and continuously covered by regularly spherical nanoparticles of a diameter close to 30 nm, e. g. typical for polypyrrole nanospheres and applied synthesis method .…”

Differences in Electrochemically Deposited PEDOT(PSS) Films on Au and Pt Substrate Electrodes: A Quartz Crystal Microbalance Study

“…The EQCM and XPS analysis results are in agreement that with increasing electrochemical deposition time, the relative difference in the PEDOT(PSS) film thicknesses on Au and Pt gradually decreases. It is interesting to note that a similar trend was observed in water contact angle measurements on PEDOT(PSS) films . While a statistically significant difference was recorded in the contact angles over thin, 0.1 μm PEDOT(PSS) films (30°±3° on Pt and 35°±4° on Au), the difference in the water contact angles over thicker, 4 μm films faded (63°±1° on Pt and 63°±4° on Au).…”

An Ionophore‐Based Anion‐Selective Optode Printed on Cellulose Paper

“…Upon contact with an aqueous sample,the anion analyte is extracted into the organic phase via ion recognition (for example, hydrogen bonding or Lewis acid-base interaction) with the ionophore.Aproton-sensitive dye (chromoionophore) is typically also doped into the organic phase as an optical read-out unit. Ionophore-based ISEs have also been designed on cellulose paper [6] and an ew paper-based plasticizer-free Na + ISO has been proposed recently by our group. Depending on the charge of the ionophore,ananion exchanger may be used to facilitate the anion extraction.…”