Three-Dimensional Inkjet-Printed Electrochemical Sensor on Shape Memory Polymer for Aqueous Lead Detection

Abstract

A simple, miniaturized, reproducible, and disposable 3D (inkjet-printed – additive manufacturing technology) gold plated electrochemical sensor (ECS) on shape memory polymer (SMP) has been reported in this article. This inkjet printed (IP) SMP based gold plated ECS is used to determine lead (II) in aqueous solution. The limit of detection of the proposed ECS is 7.6 μg/L (below USEPA approved detection limit – 15 μg/L). A detailed description of the design, fabrication, materials and reagents, optimization, reproducibility, and evaluation of the reported ECS is delineated in this article. The sensor consists of gold (Au) working electrode, Au counter electrode, and silver chloride (AgCl) reference electrode. Immersion gold plating technology is applied on IP silver (Ag) electrodes to fabricate Au working and counter electrodes. Chlorination using sodium hypochlorite solution is utilized to fabricate AgCl reference electrode. Sensor characterization, optimization, and evaluation are performed using cyclic voltammetry (CV) electrochemical analysis. The reported sensor has been utilized in case of 3 mM and 14.4 μg/L lead (II) diluted aqueous solution optimized using 0.1 M hydrochloric acid (HCl) for different aqueous samples i.e., deionized water and tap water. The electrochemical characterization i.e., electrochemical impedance spectroscopy (EIS) measurements for the reported electrode system (64.07±7.19 Ω) has also been introduced using phosphate buffer saline (PBS; pH 7.4). SMP incorporated IP ECS for lead (II) detection has been employed for the first time in this research. This technology has shown promising output in case of electrochemical sensing (lead (II) detection) due to increased effective electrode surface area (19.37 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) despite miniaturizing lateral surface area (4.19 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of the fabricated ECS.