Rational Design of Au@co-MOF Synergistic Platform for Ultrasensitive Monitoring of Dopamine in Human Biological...

This study presents the rational design and application of engineered metal-organic framework (MOF) hybrids, tailored to exhibit accelerated electron transfer kinetics and enhanced molecular recognition capabilities for the high-sensitivity detection of dopamine (DA). Specifically, an enzyme-free electrochemical sensing platform was constructed using Au@Co-MOF nanocomposites, which were synthesized via a controllable in situ growth approach. Au nanoparticles (AuNPs) were uniformly anchored onto the [Co₃(TMA)₃(H₂O)₅]_n (where TMA = 1,3,5-trimesic acid) framework containing coordinatively unsaturated Co-(II) active sites, forming the Au@Co-MOF hybrid material. Field-emission scanning electron microscopy (FESEM) characterization confirmed that the Au@Co-MOF hybrids possessed a well-defined spherical morphology with an average particle size of 7.5 μm, in clear contrast to the discrete AuNPs used for modification. The electrochemical sensing performance of the Au@Co-MOF-modified platform was systematically evaluated via differential pulse voltammetry (DPV) under optimized experimental conditions. Results demonstrated that the sensor exhibited a wide linear response range for DA, with a low limit of detection (LOD, S/N = 3) of 0.02 μM and a high sensitivity of 2.0 μA·μM^-1·cm^-2. Moreover, the proposed sensor exhibited superior selectivity and excellent stability. Its practical applicability was further confirmed through the successful determination of DA in biological matrices (urine and serum), with high recovery rates of 95.5%-104.8% (serum) and 102.8%-104.5% (urine). These results underscore the great potential of the Au@Co-MOF-modified screen-printed electrode (SPE) enzyme-free platform as a robust, sensitive, and selective electrochemical sensor for neurochemical monitoring.