Electrochemical immunosensor based on Fe3O4/MWCNTs-COOH/AuNPs nanocomposites for trace liver cancer marker alpha-fetoprotein detection

An electrochemical biosensor based on iron tetroxide (Fe 3 O 4 )/carboxylated carbon nanotubes (MWCNTs-COOH)/gold nanoparticles (AuNPs) was designed for the detection of alpha-fetoprotein (AFP), which is often used as an important indicator for the early clinical diagnosis of liver cancer markers. The Fe 3 O 4 /MWCNTs-COOH nanocomposite was synthesized by a solvothermal method and it combined with gold nanoparticles (AuNPs) deposited at the constant potential on a glassy carbon electrode to form Fe 3 O 4 /MWCNTs-COOH/AuNPs, which intensifies the electrical signal while the large active sites enable more stable immobilization of the AFP monoclonal antibodies on the electrode. The electrochemical performance of Fe 3 O 4 /MWCNTs-COOH/AuNPs was investigated in detail and the electrochemical response signal after the immune reaction with the AFP antigen-antibody was recorded. The peak current Ip of the response signal is linearly proportional to the lg c AFP in the range of 1 pg mL −1 –10 μg mL −1 , with a detection limit of 1.09034 pg mL −1 and good performance in clinical sample testing. The proposed sensor has shown great application and development potential in clinical medicine field.