Self-Polymerized Dopamine-Decorated Au NPs and Coordinated with Fe-MOF as a Dual Binding Sites and Dual Signal-Amplifying Electrochemical Aptasensor for the Detection of CEA

Fabrication of functional electrochemical biosensor is a hot topic; however, precise and sensitive cancer detection in early clinical diagnosis is still a great challenge. Continuous efforts have been devoted to explore functional materials for this issue. In this work, we developed a dual binding sites and dual signal-amplifying electrochemical aptasensor of self-polymerized dopamine-decorated Au and coordinated with Fe-MOF (Au@PDA@Fe-MOF) for the detection of carcinoembryonic antigen (CEA). Remarkably, Au@PDA@Fe-MOF features high sensitivity, multiple active sites, good biocompatibility, and excellent selectivity, which is attributed to abundant -COOH in porous Fe-MOF and unsaturated Fe³⁺ sites on the surface of Fe-MOF as the active binding sites grafting more NH₂-functionalized CEA-specific aptamer and redox PDA and Fe-MOF accelerating the movement of electrons for dual signal amplifying. Meanwhile, the electrochemical aptasensor shows favorable repeatability with 1.82% relative standard deviation (RSD) under five independent aptasensors and strong stability with only 3.3% degradation after 12 days of storage. In addition, the aptasensor has wide CEA detection range from 1 fg mL^-1 to 1 μg mL^-1 with a low detection limit of 0.33 fg mL^-1 (S/N = 3). Furthermore, the aptasensor is feasible for accurate and quantitative detection of CEA in serum samples with RSD below 2.32%. The satisfying results demonstrate promising applications of the CEA aptasensor in practical sample analysis and lay an important foundation for other biomarker detection in early clinical diagnosis.