Electrochemical Immunosensor Based on Fe3O4/PANI/AuNP Detecting Interface for Carcinoembryonic Antigen Biomarker

A low-cost screen-printed carbon electrode (SPCE) modified with Fe3O4, gold nanoparticles (AuNPs), and polyaniline (PANI) has been developed for rapid measurement of carcinoembryonic antigen (CEA) biomarker. The electrode surface was covered with Fe3O4 nanoparticles by drop coating then with PANI via electropolymerization. The resulting surface was further modified by AuNPs via electrodeposition. Key factors affecting the electrochemical behavior and sensing performance of the electrode were investigated. The results demonstrated that Fe3O4 mass loading of 2 mg/cm(2) and 15 cycles of PANI polymerization were optimal for electrochemical measurement of CEA biomarker. In addition, compared with bare SPCE, coating the electrode surface with PANI, Fe3O4/PANI, and Fe3O4/PANI/AuNP significantly enhanced the peak oxidation current by approximately 16%, 52%, and 93%, respectively. The sensors exhibited linear trends with CEA concentration from 0 ng/mL to 10 ng/mL. The limit of detection and sensitivity of the electrode were estimated to be 0.25 ng/mL and 0.3827 mu A/ng mL(-1), respectively. Such sensors could be easily integrated into microfluidic platforms and could serve as a low-cost, rapid, point-of-care measurement method for CEA cancer biomarker. [GRAPHICS]