Coupling single-atom electronic structure engineering with interfacial electrical property modulation for enhanced electrochemical sensing of dopamine and uric acid.

Dopamine (DA) and uric acid (UA) are important biomarkers whose simultaneous determination is essential for clinical diagnosis and pathophysiological studies. However, prevailing electrochemical sensors rely on conductivity enhancement or complex architectures, often resulting in ill-defined active sites that obscure clear structure-activity relationships. We integrate single-atom electronic structure engineering with interfacial electrical property modulation to precisely define atomic-scale active sites and their interfacial environment, thereby establishing clear structure-activity relationships. A ternary MXene@Mn2O3@PtSA catalyst is constructed by anchoring atomically dispersed Pt sites on Mn2O3 grown on highly conductive MXene. Electronic interactions between Pt single atoms and the Mn2O3 support downshift the Pt d-band center, optimizing the adsorption energies of reaction intermediates and significantly lowering the energy barriers of the rate-determining steps for both DA and UA oxidation, while the negatively charged surface promotes electrostatic enrichment of DA. As a result, MXene@Mn2O3@PtSA enables sensitive and selective discrimination of DA and UA in serum samples, offering a versatile design paradigm for high-performance electrochemical biosensing.