Electrochemical Nanobiosensor of Ionic Liquid Functionalized MoO3‐rGO for Sensitive Detection of Carcinoembryonic Antigen

Abstract Early diagnosis of cancer can be achieved by detecting associated biomarkers before the appearance of symptoms. Herein, we have developed an electrochemical immunosensor of ionic liquid tailored to molybdenum trioxide‐reduced graphene oxide (MoO 3 ‐rGO‐IL) nanocomposite to detect carcinoembryonic antigen (CEA), a cancer biomarker. The MoO 3 ‐rGO‐IL nanocomposite has been synthesized in situ via the hydrothermal method. The functionalization of 1‐butyl‐3‐methylimidazolium tetrafluoroborate IL with MoO 3 ‐rGO synergistically improves the electrochemical and surface properties of the nanocomposite. The characterization studies revealed that the MoO 3 ‐rGO‐IL nanocomposite is a highly appropriate material for the construction of immunosensors. The material exhibits exceptional electrical conductivity, surface properties, stability, and a large electrochemical effective surface area (13.77×10 −2 cm 2 ) making it ideal for fabricating immunosensors. The quantitative outcome showed that the developed immunosensor (BSA/anti‐CEA/MoO 3 ‐rGO‐IL/GCE) possesses excellent sensitivity, broad linearity from 25 fg mL −1 to 100 ng mL −1 , and a low detection limit of 1.19 fg mL −1 . Moreover, the remarkable selectivity, repeatability, and efficiency of detecting CEA in serum specimens demonstrated the feasibility of the immunosensor. Thus, the projected electrochemical immunosensor can potentially be utilized for the quantification of CEA in clinical specimens.