A highly sensitive sandwich-type electrochemical sensor for detection glypican-3 based on H-rGO-CMC@Pt NPs and aptamers

Glypican-3 (GPC3), which is a surface heparan sulfate proteoglycan, has been widely known the ideal biomarker for diagnosis and treatment of hepatocellular carcinoma (HCC). Accurate and sensitive detection of serum GPC3 level is an important and challenging task. In this paper, a sandwich electrochemical aptasensor was designed to specifically detect serum GPC3 level through aptamer-target-aptamer recognition. A GPC3 aptamer (GPC3_Apt) immobilized on the surface of gold nanoparticles@reduced graphene oxide modified screen-printed electrode (Au NPs@rGO/SPCE) was used as the capture probe. Hemin-reduced graphene oxide-carboxymethyl chitosan@platinum nanoparticles (H-rGO-CMC@Pt NPs), with good mimicking peroxidases activity, were labeled with amination GPC3 aptamer, which was employed as the signal probe. Once the target GPC3 was anchored on the surface of GPC3_Apt/Au NPs@rGO/SPCE, the H-rGO-CMC@Pt NPs-GPC3_Apt was further specifically bound to the GPC3, forming the aptamer-target-aptamer sandwich structure, which can catalyze the oxidation of hydroquinone (HQ) to benzoquinone (BQ) and lead the oxidation current of HQ recorded by DPV to changing. The linear relationship between the current signal of oxidation of HQ and GPC3 concentration range of 0.0001–3.0 µg/mL and 3.0–60.0 µg/mL, with a low detection limit (LOD) of 0.0685 ng/mL. Additionally, the electrochemical aptasensor was successfully applied for the detection of GPC3 in human serum samples with the recovery of 99.95–104.06 % and relative standard deviation (RSD) of 1.31–5.22 %. Thus, the sandwich aptasensor could provide a new strategy for detection of serum GPC3 level and improve the early diagnosis rate of HCC.