Sandwich-type supersensitive electrochemical aptasensor of glypican-3 based on PrGO-Hemin-PdNP and AuNP@PoPD

A new sandwich-type electrochemical biosensing platform was developed by gold @polyphthalenediamine nanohybrids (AuNP@PoPD) as the sensing platform and phosphorus doped reduced graphene oxide-hemin-palladium nanoparticles (PrGO-Hemin-PdNP) as the signal amplifier for phosphatidylinositol proteoglycan 3 (GPC3). AuNP@PoPD, co-electrodeposited into the screen printed electrode with high conductivity and stability, is dedicated to assembling the primary GPC3 aptamer (GPC3_Apt). The second GPC3_Apt immobilized on the high conductivity and large surface area of PrGO-Hemin-PdNP was utilized as an electrochemical signal reporter by hemin oxidation (PrGO-Hemin-PdNP-GPC3_Apt). In the range 0.001–10.0 ng/mL, the hemin oxidation current signal of the electrochemical aptasensor increased log-linearly with the concentration of GPC3, the lowest detection limit was 0.13 pg/mL, and the sensitivity was 2.073 μA/μM/cm². The aptasensor exhibited good sensing performance in a human serum sample with the relative error of 4.31–8.07%. The sandwich sensor showed good selectivity and stability for detection GPC3 in human serum samples, providing a new efficient and sensitive method for detecting HCC markers.