Synergistic signal amplification of ultrathin nanowire-like PtCoFeRuMo high-entropy nanozyme and Z-scheme WO3/ZnIn2S4 heterostructure for split-typed photoelectrochemical aptasensing of myoglobin

Enzyme-initiated sensing strategy has wide applications in photoelectrochemical (PEC) analysis for its high specificity and excellent catalytic efficiency. Herein, ultrathin PtCoFeRuMo high-entropy alloy nanowires (PtCoFeRuMo HEANWs) as new nanozymes were prepared by a simple solvothermal method, whose peroxidase-like (POD-like) catalytic property was critically investigated by tetramethylbenzidine (TMB) oxidation in the presence of H2O2. Simultaneously, Z-scheme WO3/ZnIn2S4 heterostructures (labeled WO3/ZnIn2S4) were constructed under solvothermal treatment, whose optical properties and photoactivity were rigorously studied by a set of techniques, combined by elaborating the interfacial charge transfer mechanism. On such foundation, a split-typed PEC aptasensor was established with the WO3/ZnIn2S4 substrate, whose detection signals were further magnified through catalytic oxidation of 3-amino-9-ethylcarbazole (AEC) initiated by the PtCoFeRuMo HEANWs. The resultant PEC sensor realized excellent bioanalysis of biomarker myoglobin, showing a broader linear range from 1.0 × 10−2 to 1.0 × 105 pg mL−1 and a lower limit of detection (0.96 fg mL−1, S/N = 3). This split-typed PEC biosensing strategy shows substantial promise in bioanalysis and clinical diagnosis.