Disposable Point-of-Care Electrochemical Sensor for Uric Acid Determination in Human Urine Utilizing a Pencil Graphite Electrode Modified with Polydopamine/Gold Nanoparticles

Abstract

Point-of-care testing (POCT) is an essential approach in clinical analysis due to its rapidity. In the current research and for the first time, we have developed an electrochemical POC sensor for uric acid (UA) determination using pencil graphite electrode (PGE) substrate modified via a facile self-polymerization of dopamine (DA). Alkaline conditions were used to produce polydopamine (PDA) which inspired from mussel adhesive protein. The PDA-modified electrode was further decorated by electrodeposition of gold nanoparticles (Au-NPs). Sensor surface characterization was conducted using surface characterization techniques like X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) imaging. In addition electrochemical characterization methods were performed utilizing electrochemical impedance spectroscopy (EIS) as well as cyclic voltammetry (CV). The sensor yielded a precise voltammetric response upon using differential pulse voltammetry (DPV) (linearity range: 5.0 × 10−5 mol l−1 − 5.0 × 10−4 mol l−1 of UA with 1.57 × 10–5 mol l−1 limit of detection). The developed sensor’s benefits include decreased manufacturing cost and selectivity. Accurate and satisfactory results were obtained upon application to human urine sample analysis.