Glypican-3 electrochemical aptasensor based on reduced graphene oxide‐chitosan‐ferrocene deposition of platinum–palladium bimetallic nanoparticles

In this study, a new electrochemical aptasensor with specific identification and quantitative analysis of glypican-3 (GPC3) was constructed using reduced graphene oxide-chitosan-ferrocene deposition of Pt–Pd bimetallic nanoparticles (RGO-CS-Fc/Pt–Pd BNPs) as biosensing platform and GPC3 aptamer (GPC3apt) as recognition molecule. The GPC3apt could react specifically with GPC3 present in the experimental samples, resulting in the formation of GPC3-aptamer complexes on the biosensing platform, which would increase the electron transfer impedance and reduce the redox current of ferrocene. The electrochemical aptasensor was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectrometry (EIS), and Raman spectroscopy. Under the optimal experimental conditions, the response redox current was linearly related to the concentration of GPC3 in the range from 0.001 to 10 µg mL−1 with good linear correlation coefficient (R2 of 0.9929), and had a low detection limit of 3.67 ng mL−1 (S/N = 3), high sensitivity of 0.149 µA µM−1 cm−2. In addition, the aptasensor showed long stability, good specificity, acceptable reproducibility and satisfactory recoveries (101.1–105.6%) in the detection of clinical serum samples, which developed a new research method for early clinical diagnosis.