GPC3 Electrochemical Aptasensor Based on Pd-Pt NPs@ RGO-H Nanozyme to Catalyze Silver Deposition

Pd-Pt NPs@RGO-H nanozyme with good peroxise-like properties, high electrical conductivity, and high specific surface area was prepared. The nanozyme was combined with Glypican-3 aptamer (GPC3Apt) to form a signal probe. Another GPC3Apt was employed as a capture probe, and it was incubated on the surface of the screen-printed electrode that had been plated with Au NPs@rGO. To catalyze silver deposition, a sandwich-type electrochemical aptasensor based on Pd-Pt NPs@RGO-H nanozyme was built in the presence of GPC3 protein. When hydrogen peroxide and silver nitrate were added to the surface of the electrochemical aptasensor, Pd-Pt NPs@RGO-H can effectively catalyze the deposition of silver ions (Ag+) on the electrode surface to elemental silver (Ag0) due to its peroxise-like properties. The silver current fluctuation was measured using the Differential Pulse Voltammetry (DPV) method. When the concentration of GPC3 was between 1.0 and 70.0 μg/mL, the linear equation was Y=0.2822X +22.6428 (the response current is Y, and the GPC3 concentration is X) with the correlation coefficient of 0.9956, and the lowest detection line was 480 ng/mL. Furthermore, the electrochemical aptasensor demonstrated high specificity and stability.