Construction of highly sensitive electrochemical immunosensor based on Au and Co₃O₄ nanoparticles functionalized Ni/Co bimetal conductive MOF for quantitative detection of HBsAg

Herein, highly sensitive electrochemical immunosensor based on noble metal and metal oxide nanoparticles functionalized bimetal conductive metal–organic frameworks (c-MOFs) was proposed toward HBsAg detection. The nanorod-like architecture of Ni₃(HITP)₂c-MOFs was synthesised via a simple and facile route, followed by dopant coble ions formation cobaltosic oxide (Co₃O₄) nanoparticles decorated bimetal NiCo(HITP) c-MOFs nanocomposites. Benefiting from large specific surface area, high electrical conductivity and abundant active sites of desirable nanostructures, the resultant Co₃O₄NPS/NiCo(HITP) bimetal c-MOFs nanostructure exhibits fast electron transfer capability and effective specific binding between antigen and antibody. Meanwhile, different amounts of Au nanoparticles were further functionalized on Co₃O₄NPS/NiCo(HITP) nanocomposites to further improve the electrochemical properties. Under optimum condition, the as-proposed Au@Co₃O₄NPS/NiCo(HITP) electrochemical immunosensor exhibits superior sensing performances toward HBsAg including wide linear response range from 1 pg mL⁻¹ to 100 ng mL⁻¹ and low detection limit of 15 fg mL⁻¹ (S/N = 3). Meanwhile, the as-fabricated electrochemical immunosensors also displays outstanding selectivity, repeatability and stability. Besides, quantitative detection of HBsAg also achieves satisfactory results in real sample detection. Thereby, our work not only provides a promising strategy to construct highly sensitive electrochemical immunosensor using hybrid c-MOFs nanomaterials but also presents a potential application in the early diagnosis of hepatitis B-related diseases.