Core-shell structured carbon nanofiber-supported bristlegrass-like conductive metal‐organic framework Cu3(HHTP)2 nanorod arrays for electrochemical and colorimetric dual-mode detection of dopamine in serum

Abstract

Dopamine (DA) is a central neurotransmitter that plays a crucial role in human metabolism. Its precise detection is of great importance in disease diagnosis. Compared with single-signal detection methods, colorimetric and electrochemical dual-signal outputs can self-validate the measured data and counteract interference effects, which is expected to provide more reliable detection results. In this paper, carbon nanofiber-supported 3D bristlegrass-like π-conjugated conducting metal–organic frameworks (cMOF) Cu₃(HHTP)₂ nanorod arrays (Cu₃(HHTP)₂ NRAs/CNF) catalyst with  core–shell structure are synthesized by electrospinning and solvothermal reaction. The obtained catalyst possesses remarkable peroxidase-like activity which can catalyze the colorless 3,3′,5,5′ −tetramethylbenzidine (TMB) to blue oxTMB. The mechanism study showes that ·OH radicals are the main active substances. Meanwhile, the core–shell structure between π-conjugated cMOF and CNF can effectively inhibit the aggregation of Cu₃(HHTP)₂ nanorods and generate more catalytic active sites, resulting in strong electrocatalytic activity of Cu₃(HHTP)₂ NRAs/CNF. As a result, a novel dual-mode sensor based on colorimetric and electrochemical are constructed for detecting dopamine (DA) with a good linear relationship ranging from 2.5-60 μM and 0.1–106 μM, and the limit of detection (LOD) are 0.27 μM and 10.1 nM (S/N=3), respectively. This study opens up a new idea for the application of cMOF peroxidase-like enzyme in sensing field.