Porous polymer-modified metal–organic framework (AM@UIO-66-NH2) for electrochemical detection of dopamine in human serum

Abstract

Neurotransmitters (NTs) are essential for brain functions, cognition, and behavior as they transmit, amplify, and convert cellular signals, facilitating neuronal communication and regulating physiological processes. Dopamine (DA) acts both as an NTs and a hormone, contributing to reduced insulin production and decreased lymphocyte activity within the immune system. Metal–organic frameworks (MOFs), as emerging nanomaterials for biosensing, offer high porosity, large surface areas, facile functionalization, and tunable architectures. In this study, an amine-functionalized zirconium MOF was modified with synthetic allomelanin (AM) (AM@UIO-66-NH₂) for highly efficient DA detection. The morphology, elemental composition, functional groups, crystalline phases, thermal stability, surface area, and electrochemical properties of the synthesized material were characterized via spectroscopic and analytical techniques. Square wave voltammetry (SWV) and chronoamperometry (CA) were employed to assess the DA detection limit (LOD). The optimized sensor demonstrated a linear DA detection range of 30–1000 nM, with LODs of 18 nM for SWV and 24 nM for CA. High-sensitivity detection of DA in human serum was achieved. In the presence of interferents, AM@UIO-66-NH₂ selectively oxidized DA and maintained its stability over 100 cycles. The developed composite shows great potential for DA detection in clinical diagnostics, demonstrating excellent sensitivity, reproducibility, and stability in serum samples.