In this work, a sandwich-type electrochemical immunosensor was fabricated to the effective detection of hepatitis B surface antigen (HBsAg). The designed electrochemical immunosensor was based on Au core and Pd shell nanodendrites loaded on amino functionalized molybdenum dioxide nanosheets (Au@Pd NDS/NH₂–MoO₂ NSs) as the secondary antibody (Ab₂) label and silver nanoparticles were loaded by electrodeposited (D-Ag NPs) on the surface of electrode as the platform. Because of the synergistic effect and abundant catalytic activity sites provided by surface dendrite structure, Au@Pd NDs were more effective than single gold and palladium nanoparticles in catalytic reduction of hydrogen peroxide (H₂O₂). MoO₂ had the good catalytic capacity for reduction of H₂O₂ and favourable electrical conductivity. Hence, the obtained Au@Pd NDS/NH₂–MoO₂ NSs were more effective than Au@Pd NDs and NH₂–MoO₂ NSs in catalytic reduction of hydrogen peroxide attribute to a synergistic effect. Also, Ag NPs with admirable electrical conductivity and biocompatibility were used as sensing platforms and primary antibodies (Ab₁) carriers, which can accelerate the electron transfer and improve the sensitivity of the immunosensor. Here, the proposed electrochemical immunosensor offered a wide linear interval from 10 fg mL⁻¹ to 100 ng mL⁻¹ and the lower limit of detection of 3.3 fg mL⁻¹ (S/N = 3) for detection of HBsAg under optimal experimental conditions. Furthermore, the accuracy of the actual serum sample analysis was satisfactory, which showed that the electrochemical immunosensor possessed a good application prospect in clinical detection.

在这项工作中，制造了一种三明治型电化学免疫传感器以有效检测乙型肝炎表面抗原（HBsAg）。设计的电化学免疫传感器基于负载在氨基官能化的二氧化钼纳米片（Au @ Pd NDS / NH ₂ -MoO ₂ NSs）上的Au核和Pd壳纳米枝晶作为第二抗体（Ab ₂）标签，并通过电沉积（以电极表面为平台的D-Ag NPs）。由于表面枝晶结构的协同作用和丰富的催化活性位，Au @ Pd NDs在催化还原过氧化氢（H ₂ O ₂）方面比单个金和钯纳米粒子更有效。O₂具有良好的还原H ₂ O _2的催化能力和良好的导电性。因此，获得的Au @ Pd NDS / NH ₂ -MoO ₂ NSs比Au @ Pd NDs和NH ₂ -MoO ₂ NSs更有效地催化了过氧化氢的协同作用。同样，具有良好电导率和生物相容性的Ag NPs被用作传感平台和一抗（Ab ₁）载体，可以加速电子转移并提高免疫传感器的灵敏度。在此，拟议的电化学免疫传感器提供了从10 fg mL ^-1到100 ng mL的宽线性区间^-1和在最佳实验条件下检测HBsAg的检测下限为3.3 fg mL ^-1（S / N = 3）。此外，实际血清样品分析的准确性令人满意，表明电化学免疫传感器在临床检测中具有良好的应用前景。