Label-Free Immunosensor Based on Polyaniline-Loaded MXene and Gold-Decorated β-Cyclodextrin for Efficient Detection of Carcinoembryonic Antigen.

Multiple strategies have been employed to improve the performance of label-free immunosensors, among which building highly conductive interfaces and introducing suitable biocompatible carriers for immobilizing antibodies or antigens are believed to be efficient in most cases. Inspired by this, a label-free immunosensor for carcinoembryonic antigen (CEA) detection was constructed by assembling AuNPs and β-CD (Au-β-CD) on the surface of FTO modified with PANI-decorated f-MXene (MXene@PANI). Driven by the high electron conductivity of MXene@PANI and the excellent capability of Au-β-CD for antibody immobilization, the BSA/anti-CEA/Au-β-CD/MXene@PANI/FTO immunosensor exhibits balanced performance towards CEA detection, with a practical linear range of 0.5-350 ng/mL and a low detection limit of 0.0429 ng/mL. Meanwhile, the proposed sensor presents satisfying selectivity, repeatability, and stability, as well as feasibility in clinic serum samples. This work would enlighten the prospective research on the alternative strategies in constructing advanced immunosensors.