1：Experimental Design and Method Selection:

The study utilized a graphene field-effect transistor (G-FET) functionalized with 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE) for the immobilization of an anti-AFP antibody. The detection of AFP was based on the shift in the voltage of the Dirac point (?VDirac) after AFP binding.

2：Sample Selection and Data Sources:

Human plasma samples from HCC patients were used, with AFP concentrations verified at Keimyung University School of Medicine. AFP was also detected in phosphate buffer saline (PBS) solution for comparison.

3：List of Experimental Equipment and Materials:

G-FET biosensor, PBASE, anti-AFP antibody, AFP, human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), bovine serum albumin (BSA), and large-sized graphene on a PET substrate.

4：Experimental Procedures and Operational Workflow:

The G-FET was functionalized with PBASE, followed by anti-AFP antibody immobilization. AFP detection was performed by measuring the shift in the Dirac point voltage after AFP binding in PBS and HCC patient plasma.

5：Data Analysis Methods:

The sensitivity of the G-FET biosensor was evaluated by assessing the shift in the Dirac point voltage (?VDirac). The dissociation constant (KD) for the anti-AFP and AFP interaction was estimated using the Langmuir equation.