Electrochemical Aptamer Sensor Based on rGO-Pd-PB for Efficient Detection of Golgi Protein 73

Golgi protein 73 (GP73) is a novel serum marker for hepatocellular carcinoma (HCC) screening and diagnosis. In this study, we developed a sandwich electrochemical sensor for GP73 detection utilizing reduced graphene oxide-palladium nanoparticles-Prussian blue (RGO-Pd-PB) nanomaterial as the core detection element. RGO-Pd-PB nanomaterial exhibited peroxidase-like activity and were conjugated with a GP73-specific aptamer to form the signal recognition probe (RGO-Pd-PB-Apt). A GP73 aptamer was immobilized onto gold nanoparticles modified screen-printed electrode (Au NPs/SPE) to create the capture probe. Upon GP73 binding, a sandwich complex (RGO-Pd-PB-Apt/GP73/Apt/Au NPs/SPE) was formed. This complex catalyzed H 2 O 2 -mediated silver deposition, where the resulting silver ion signal intensity quantitatively correlated with GP73 concentration. The sensor demonstrated excellent performance, achieving a detection limit of 0.033 ng ml −1 and a linear detection range of 1.0 to 100.0 ng ml −1 . Validation in human serum samples showed strong agreement with enzyme-linked immunosorbent assay results, with relative errors between 1.02% and 7.27% and relative standard deviations ranging from 1.29% to 5.94%. This electrochemical aptamer biosensor demonstrated high specificity, sensitivity, reproducibility, and stability, providing a promising new platform for the early HCC detection.