Advanced 2D MoS2–chitosan nanocomposites for ultra-sensitive and selective dopamine detection

Abstract

Dopamine, an essential neurotransmitter in the central nervous system, plays a key role in neurological disorders such as Parkinson's disease, making its accurate monitoring critical for effective prevention, diagnosis, and management. This study introduces a novel and cost-effective electrochemical sensor for dopamine detection, leveraging molybdenum disulfide–chitosan (Cs–MoS₂) nanohybrids synthesized via a simple liquid-phase exfoliation (LPE) method. Chitosan nanoparticles were dispersed in a solution containing molybdenum disulphide (MoS₂) nanosheets to form the Cs–MoS₂ nanohybrids. These nanohybrids were extensively characterized using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), and atomic force microscopy (AFM), confirming their successful synthesis and unique properties. Commercial screen-printed electrodes (SPEs) were modified with the Cs–MoS₂ nanohybrids and evaluated for dopamine sensing through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The sensor exhibited high sensitivity, with two distinct linear response ranges: 4.48 μA μM⁻¹ cm⁻² for 0–40 μM and 1.67 μA μM⁻¹ cm⁻² for 40–440 μM. The limit of detection (LOD) was determined to be 0.8 μM. These performance metrics demonstrate superior analytical capabilities, including excellent selectivity against common interfering species in body fluids, good stability, and reproducibility. The findings underline the novelty of utilizing Cs–MoS₂ nanohybrids in electrochemical dopamine detection and highlight their potential for practical applications in biomedical diagnostics.