AuNPs-TiS₂ modified label-free ultrasensitive electrochemical immunosensor for carcinoembryonic antigen (CEA)...

In this study, a novel immunosensor for carcinoembryonic antigen (CEA) determination was designed, and the synergistic effect of zero-dimensional gold nanoparticles and two-dimensional nanomaterials TiS₂ was investigated. In this regard, gold nanoparticles were electrochemically deposited on the surface of the screen-printed electrode (SPE), with MAU employed as a surface activation agent following the insertion of TiS₂ nanosheets. The anti-CEA was attached to the surface through EDC/NHS chemistry, utilizing the carboxy end of MUA attached to AuNPs and TiS₂ nanosheets. The resulting structure was subsequently protected by Nafion, and non-specific binding to the surface was prevented by the addition of bovine serum albumin (BSA). In a similar manner, an immunosensor was formulated that did not contain TiS₂. CEA quantification was executed via an impedimetric approach. A comprehensive evaluation of the impedimetric outcomes indicated that the immunosensor comprising AuNPs alone was inadequate in achieving an accurate measurement range. Nevertheless, an immunosensor with a very low concentration range (1-100 pg/mL) and a low limit of detection (LOD, 0.21 pg/mL) value could be prepared through the synergistic effect of TiS₂. The AuNPs-TiS₂-based immunosensor exhibits both high selectivity and reproducibility. Furthermore, the immunosensor exhibits noteworthy storage stability, thus making it well-suited for the quantification of CEA in biological specimens, such as blood. The properties described herein serve to substantiate the hypothesis that the Au-TiS₂-based immunosensor is a promising candidate for clinical applications.