Graphene‐Oxide‐Loaded Fe₃O₄‐Pd‐Ag Nanoparticles Allow Sensitive Detection of CEA through a Signal Enhancement Strategy**

Abstract

Using graphene oxide (GO)-loaded Fe 3 O 4 -Pd-Ag (GO/Fe 3 O 4 -Pd-Ag) nanoparticles on a gold electrode as a platform, an unlabeled electrochemical immunosensor was fabricated in this study to detect the carcinoembryonic antigen (CEA) with high sensitivity. After modification, the stability and strength of the signal are improved by the increased effective area of the electrode and the synergistic effect of the silver nanoparticles with GO, Fe 3 O 4 , and Pd. The signal intensity decreased as the concentration of CEA increased. Using cyclic voltammetry and electrochemical impedance spectroscopy, the immunosensor layer assembly process was validated. Under optimal conditions, the electrochemical immunosensor had a detection range of 1 pg mL À 1 to 80 ng mL À 1 . The linear equation was I (μA) = 304.563-41.867 × logc CEA (ng mL À 1 ), the correlation coefficient was 0.9967, and the detection limit was 0.2 pg mL À 1 . In addition, the modified electrochemical immunosensor exhibited high selectivity, stability, and repeatability. This electrochemical immunosensor shows a good application prospect in the detection of tumor marker CEA.

Realizing the label-free sensitive detection of carcinoembryogenic antigen (CEA) in blood serum via a MNC-decorated flexible immunosensor

“…With the advancements in nanotechnology and materials science, a variety of composites such as noble and non-noble metal nanoparticles, quantum dots, metal oxides, electroactive component-capture nanoparticles, [21][22][23][24][25] conducting and non-conducting polymers, and carbonaceous materialbased composites have been explored as transduction materials for the sensitive, fouling-free, and label-free electrochemical detection of CEA. [26][27][28][29] However, till date, the development of label-free electrochemical immunosensors has been limited by their low sensitivity due to the complex substrate fabrication procedures, use of costly coupling agents, and instability of the probe. As a result, the choice of transducing material is the key step in the fabrication of immunosensors under physiological conditions without the use of any coupling or blocking agent.…”