Amperometric low potential aptasensor for the fucosylated Golgi protein 73, a marker for hepatocellular carcinoma

The fucosylated Golgi protein 73 (fuc-GP73) has been used as a criterion to distinguish hepatocellular carcinoma (HCC) from other chronic liver diseases. We describe an amperometric aptasensor for ultrasensitive detection of fuc-GP73 that uses a thiolated aptamer against GP73 as the capture probe, and gold nanoparticles (AuNPs) modified with Avidinlens culinaris agglutinin (A-LCA) as the detection probe. The AuNPs on the surface of a gold electrode provide a large surface for immobilization of A-LCA, so that they can be heavily loaded with biotinylated horse radish peroxidase (B-HRP) via avidin-biotin interactions. This results in enhanced analytical sensitivity. Under optimized conditions and a typical working potential as low as 48 mV (vs. SCE), the dynamic response of the electrode covers the 10 pg·mL⁻¹ to 25 ng·mL⁻¹ fuc-GP73 concentation range, with a 7 pg·mL⁻¹ detection limit (for an S/N ratio of 3). The assay is precise, selective and reproducible. It was applied to the determination of fuc-GP73 in serum. .