Ti3C2 MXene anchors CuAu-LDH multifunctional two-dimensional nanomaterials for dual-mode detection of CEA in electrochemical immunosensors

Electrochemical immunoassays are commonly used to detect biomarkers and Ti3C2 MXene anchored CuAu-LDH two-dimensional hydroxide heterojunctions for dual-mode electrochemical immunosensors were fabricated in this work. Layered double hydroxides have a large surface area, high chemical stability, tunable metal composition and interchangeable anions, however, the insulating nature of LDH further limits its catalytic performance. For this reason, Ti3C2 Mxenes were introduced to improve this problem. 2D layers of Ti3C2 Mxenes with large specific surface area and excellent conductivity have been well proven and widely used. And the surface of Ti3C2 Mxenes (due to the presence of abundant surface functional groups), will facilitate the anchoring of metal ions and the nucleation of LDH. In addition, its excellent electrical conductivity will facilitate the electron transfer between Cu2+ and Cu+. The immunosensor not only showed a heavy square wave voltammetry (SWV) signal. It also exhibited high electrocatalytic activity for H2O2 redox reactions and improves the sensitivity of the Ampere Current (i-t) detection. The CEA immunosensor developed in this study showed a wide linear response (0.0001-80 ng/mL) and the lowest detection limits (SWV: 33.6 fg/mL and i-t: 45.4 fg/mL S/N = 3). The results confirmed the excellent analytical capability of the immunosensor.