Electrochemical detection of alpha-fetoprotein using graphene-assisted sensors: A novel approach for liver cancer screening

This study presents a novel electrochemical immunosensor for the detection of alpha-fetoprotein (AFP) based on a toluidine blue-gold-Fe 3 O 4 -reduced graphene oxide (TB-Au-Fe 3 O 4 -rGO) nanocomposite. The multifunctionalized graphene platform was synthesized and characterized using SEM, TEM, XRD, and FTIR spectroscopy. Electrochemical characterization revealed enhanced electron transfer kinetics, with the TB-Au-Fe 3 O 4 -rGO electrode exhibiting the lowest charge transfer resistance of 43 Ω. Optimization of antibody immobilization and assay conditions resulted in a sensitive and selective immunosensor. The sensor showed a direct correlation with AFP levels ranging from 0.1 to 500 ng/mL, and was able to detect concentrations as low as 0.03 ng/mL. Selectivity studies showed minimal interference from common serum proteins, even at 100-fold higher concentrations. The immunosensor showed consistent results with a relative standard deviation of 3.8 % from 5 replicates, and retained more than 95 % of its original signal after being stored at 4°C for 30 days. Analysis of clinical serum samples showed excellent agreement with ELISA results (R 2 = 0.998) and recovery rates between 96.5 % and 103.8 % for spiked samples. The rapid response time of 35 seconds and simple operation make this platform promising for point-of-care liver cancer screening. This work demonstrates the potential of multifunctionalized graphene nanocomposites for enhancing the performance of electrochemical immunosensors in clinical diagnostics.