Au@Zr-based metal–organic framework composite as an immunosensing platform for determination of hepatitis B virus surface antigen

An ultrasensitive electrochemical immunosensor has been prepared using an immunofunctionalized zirconium (Zr)-based metal–organic framework (MOF) with gold (Au) decoration Au@UiO-66(NH₂) composite-coated glassy carbon electrode (GCE) for the determination of infectious hepatitis B surface antigen (HBsAg). We fabricated GCE with specific composite via immune-functionalization using anti-HBsAg with Au nanoparticles embedded in UiO-66(NH₂). The electrochemical sensing performance of the immunofunctionalized Au@UiO-66(NH₂)/GCE with HBsAg was characterized by cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, there was a linear dynamic relationship in the buffer system between the electrical signal and HBsAg levels over the range 1.13 fg mL⁻¹–100 ng mL⁻¹ (R² = 0.999) with a detection limit of 1.13 fg mL⁻¹. The total analysis time was 15 min per sample. Further validations were performed with HBsAg-spiked human serum samples, and similar detection limits as in the buffer system were observed with reduced signal intensities at lower concentrations of HBsAg (1, 10, and 100 fg mL⁻¹) and minimal interference. The HBsAg electrochemical immunosensing assay had good selectivity and excellent reproducibility, thereby indicating its significant potential in the super-fast diagnosis of hepatitis B. Graphical abstract: [Figure not available: see fulltext.].