Simultaneous Electrochemical Detection of DA and 5-HT Using Pt-Doped-rGO Nanocomposite

Abstract

An electrochemical sensor with excellent sensitivity has been developed for the continuous and selective identification of (DA) dopamine and (5-HT) serotonin via a platinum (pt) - doped reduced graphene oxide nanocomposite (Pt-doped rGO). The sensor utilizes the synergistic properties of its components: the increased surface area and electrical conductivity of rGO, the improved electron transfers due to platinum doping, and the structural benefits of the composite for efficient neurotransmitter detection. The Pt-doped rGO nanocomposite is produced by directly oxidizing graphite to generate graphene oxide (GO), subsequently reducing and functionalizing GO with platinum nanoparticles. Electrochemical characterization using differential pulse voltammetry (DPV) demonstrated clear separation of oxidation peaks for DA and 5-HT, allowing precise multiplexed detection. The sensor demonstrated superior electrocatalytic activity, selectivity, and no interference from ascorbic acid (AA), frequently found in electrochemical biosensing. The detection limits were 0.012 µM for both dopamine (DA) and serotonin (5-HT). The analysis of actual samples in human urine and serum validated the sensor’s practicality and reproducibility. The Pt-doped rGO composite effectively tackles significant issues in electrochemical biosensing, such as overlapping redox potentials and interference from intricate biological matrices, rendering it a promising platform for the highly sensitive and selective detection of neurotransmitters.