Developing an Impedimetric Aptasensor for Selective Label–Free Detection of CEA as a Cancer Biomarker Based on Gold Nanoparticles Loaded in Functionalized Mesoporous Silica Films

This study aims at designing a novel impedimetric aptasensor to determine carcinoembryonic antigen (CEA). The CEA aptasensor was developed by covalent immobilization of an amine-modified CEA aptamer on the surface of a glassy carbon electrode (GCE) which was modified by gold nanoparticles (AuNPs) incorporated in amino-functionalized MCM–41 (AMCM). After the aptamer was immobilized, CEA was incubated on the surface of an Ap-GA-AuNPs/AMCM-GCE. The change in the interfacial charge transfer resistance (R ct ) of the redox marker served as an excellent signal for the quantitative determination of CEA. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to display the aptamer immobilization on the electrode surface. Through the EIS method, the linear range and the detection limit of CEA were found to be 1.0 × 10 −3 −100.0 ng mL −1 and 9.8 × 10 −4 ng mL −1 respectively. Moreover, the proposed aptasensor was used to determine of CEA in patient and healthy human serum samples and the results indicated that this aptasensor has great potential for practical application which the strength point of this aptasensor.