Solid‐state ion sensor for on‐chip determination of potassium ion in body fluid

Abstract

AbstractThis article describes a synthetic route for the fabrication of all‐solid‐state potentiometric ion‐sensing device for on‐chip determination of potassium ion in body fluid. The sensing electrodes comprised of (a) a solid‐state reference electrode made from a Ag/AgCl‐printed electrode covered with a solid‐electrolyte‐embedded membrane made from siloxane polymer and (b) solid‐state ion‐selective electrode as working electrode made by assembling ionophore‐impregnated PVC membrane casting solution over a ion exchanger‐impregnated membrane. The ion exchanger‐impregnated membrane is cast by assembling siloxane–polyindole nanodispersion over working electrode of screen‐printed electrode to yield constant dipolar potential. The screen‐printed electrodes comprising of all‐solid‐state reference and working electrode can be operated under zero current flow to monitor potassium ion in given sample. The configuration of the printed electrodes is designed to fix a microneedle assembly over the working portion of both reference and working electrodes for transdermal ion sensing. The functional alkoxysilanes derived from nanodispersion allow to make solid‐state reference electrode avoiding the use of internal filling solution providing innovation in designing potentiometric sensor. In one aspect, a potentiometric device for detecting analyte in biological fluid that can include a array of hollowed microneedle in which each needle acts as protruded needle structure including an exterior wall forming a hollow interior covering both solid‐state working and reference electrode with an opening at terminal end in such that one microneedle is converted into a potassium ion‐selective electrode.