Towards Protein Assays on Paper Platforms with Potentiometric Detection

Abstract

Microfluidic paper-based assays represent a new approach to address the need for simple and cost-effective medical diagnostics. In an effort to couple paper-based assays with a similarly simple signal transduction, here we explored the feasibility of using potentiometric detection as a new modality to quantify affinity assays performed on a paper platform. As proof of principle a dot-blot model assay based on using IgE aptamer-gold nanoparticle conjugates was developed for the quantitative determination of IgE. The gold nanoparticle conjugates further catalyzed the deposition of silver nanoparticles that by oxidative dissolution generated silver ions. The silver ions were detected directly in the wet paper matrix by using a silver ion selective electrode. The analytical performance of potentiometric dot-blot assay matched that of reflectance-based assays, which suggests that potentiometric detection might represent a viable alternative to the conventionally used optical detection.

Electrochemical paper‐based microfluidic devices

“…Recent work has incorporated paper as a lower cost and disposable platform for one time use tests [19,91]. Szucs et al created a unique system using ISMs to detect immunoglobulin E quantitatively in paper [92]. Spot tests of IgE were incubated with immunoglobulin E aptamer conjugated AuNPs, followed by the deposition of silver onto the AuNPs.…”

Photophysical Properties of Intramolecular Charge Transfer in a Tribranched Donor–π–Acceptor Chromophore

“…Paper as a substrate for sensors has already become a subject of few review articles that include recent advances, methods of fabrication as well as the history of paper‐based analytics[15–17]. Several paper‐based potentiometric sensors were already presented, including: ion‐selective electrodes for K + , ${{\rm NH}{{+\hfill \atop 4\hfill}}}$ and pH[18], sensor for analysis of lithium ions in blood 19 and a potentiometric immunoassay 20.…”

Point-of-Care Diagnostics

“…1.2c), adopting folding techniques [119] and microplate paper platforms [120]. NP-based detection has been demonstrated with metabolites [109,111,113,117,121,147], bacterial agents [112] in disease diagnosis such as HIV [119], malaria [115], tuberculosis [120] and in environmental monitoring [114,118]. To multiplex the assay, monodisperse latex can be coupled with fluorescent and coloured dyes, and para/magnetic components.…”