Abstract
Nanostructured materials are materials engineered at the nanoscale (1–100 nm) that exhibit distinct physical and chemical properties compared to bulk materials, including high surface area and enhanced catalytic activity[1]. These unique characteristics make them ideal for electrochemical sensing applications[1]. Neurotransmitters are chemical messengers that play vital roles in transmitting signals within the nervous system, regulating physiological processes such as motor control, mood, and cognition[2]. Imbalances in key neurotransmitters like dopamine and epinephrine are associated with neurological disorders, including Parkinson’s disease and schizophrenia. The aim of this study was to develop and optimize efficient and reliable electrochemical sensors based on nanostructured materials for the sensitive and selective detection of neurotransmitters, thereby contributing to innovative diagnostic solutions with potential impact in clinical and healthcare applications. This study presents the synthesis, characterization, and electrochemical application of nanostructured silver chromate (Ag2CrO4) and polymer-supported silver nanoparticle hybrid materials for the sensitive and selective detection of neurotransmitters, including dopamine and epinephrine. Two novel catalysts, aminosalicylic acid-stabilized nano Ag2CrO4 (n-SCO) and poly-aminosalicylic acid-supported silver nanoparticles (Ag-PASA), were synthesized via organic-inorganic complexation and UV-mediated reduction methods, respectively. Comprehensive characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and UV–vis spectroscopy confirmed the successful formation, morphology, and chemical composition of the nanomaterials. Electrochemical sensing performance was evaluated using cyclic voltammetry, differential pulse voltammetry, and chronoamperometry, demonstrating high selectivity, reproducibility, and low detection limits for dopamine (LOD of 1.05 μM; sensitivity of 2.68 μA μM⁻¹ cm⁻²) and epinephrine (LOD of 0.82 μM; sensitivity of 4.52 μA μM⁻¹ cm⁻²) under physiological pH conditions. The n-SCO modified electrodes exhibited excellent stability and interferent resistance, while the Ag-PASA hybrid material enabled extended gate field effect transistor (EGFET) based sensing with reliable voltage modulation and high sensitivity (LOD of 0.72 μM). Furthermore, integration of these nanostructured sensors with an Internet of Things (IoT) platform utilizing Arduino Uno R4 microcontrollers and Wi-Fi-enabled ESP32 chips facilitated real-time remote monitoring and data transmission to cloud-based services. This IoT-enabled system offers promising potential for telemedicine and portable diagnostics with scalable, energy-efficient operation. The findings highlight the synergistic effect of tailored nanomaterials and advanced electronics to create versatile, low-cost, and high-performance sensors for neurotransmitter detection, advancing the frontier of personalized healthcare technologies.