Staple-based paper electrochemical platform for celiac disease diagnosis

Abstract

A staple-based electrochemical platform is proposed for the first time as a simple and low-cost detection system for paper-based devices. The system, that incorporates small and disposable stainless-steel staples as electrodes (modified with carbon ink in the case of the working electrode) is combined with a paper strip and is carefully optimized with ferrocene carboxylic acid. As a proof-of-concept, it was employed for the enzymatic (HRP-based) immunoelectroanalytical detection of human tissue anti-transglutaminase (anti-tTG), biomarker for celiac disease diagnosis. The intensity of the current due to the electrochemical reduction of TMB (HRP substrate) was recorded chronoamperometrically at -0.2 V in different paper areas. A linear relationship between the current measured at 30 s and the logarithm of the concentration of anti-tTG in the range comprised between 3 and 100 U.mL-1 was obtained. Negative and positive controls produced expected values. Results demonstrated that the paper/staple-combined platform is very convenient for the detection of electroactive analytes and other compounds that can be determined indirectly in bioassays.