An Ultrasensitive Immunosensor for the Detection of Carcinoembryonic Antigens Utilizing a Nb-Doped Titanium Dioxide Nanocomposite Film

An ultrasensitive electrochemical immunosensor based on Nb-doped titanium dioxide was developed for detection of carcinoembryonic antigen (CEA). The electrochemical signal enhancement was due to the synergistic effect by NbT and nanogold. The influence factors (pH, temperature and incubation time) were investigated in detail. Under optimal conditions, the immunosensor was able to detect the concentration of CEA in the range of 0.5 ng ⋅ mL-1 to 150 ng ⋅ mL-1, with a lower detection limit of 8.95 pg ⋅ mL-1. The proposed immunosensor showed high sensitivity, excellent selectivity and good stability.