癌胚抗原（CEA）是一种用于监测癌症治疗的癌症标志物。本文提出了一种无标记电化学免疫传感器来确定由硫醇化壳聚糖（tCHI）和掺杂的聚（N-甲基苯胺）（dPNMA）组成的CEA浓度。tCHI用作CEA抗体（anti-CEA）固定的支持基质，并采用11-硫辛酸（MUA）作为移植剂在壳聚糖（CHI）上制备。dPNMA的优异电导率被用作所提出的免疫传感器的电子传递层。通过衰减全反射傅里叶变换光谱（ATR-FTIR）、X射线光电子能谱（XPS）和扫描电子显微镜（SEM）确认了tCHI的成功制备。循环伏安法（CV）、差分脉冲伏安法（DPV）和电化学阻抗谱（EIS）被用来说明所提出的免疫传感器的性能。CEA浓度的确定依赖于随着CEA浓度的增加而减少DPV电流响应的抗原-抗体免疫复合物的形成。所提出的免疫传感器展示了0.01至30 ng/ml的广泛浓度范围，并具有低检测限（LOD）为0.01 ng/ml。此外，当前传感器表现出优异的选择性，重复性和长期稳定性，表明其在临床免疫测定中确定CEA的潜力。版权所有©2023 Elsevier B.V.。

Carcinoembryonic antigen (CEA) is a cancer marker used for monitoring cancer treatment. Herein, a label-free electrochemical immunosensor for determining CEA concentration composed of the thiolated chitosan (tCHI) and the doped poly(N-methylaniline) (dPNMA) is proposed. The tCHI served as a support matrix for the immobilization of CEA antibodies (anti-CEA) and was prepared by using 11-mercaptoundecanoic acid (MUA) as a grafting agent on chitosan (CHI). The excellent electrical conductivity of the dPNMA was utilized as an electron transfer layer for the proposed immunosensor. The successful preparation of the tCHI was confirmed by the attenuated-total reflection Fourier transform spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to illustrate the performance of the proposed immunosensor. The determination of CEA concentration was relied on the decrease in the DPV current response with increasing CEA concentration from the creation of the antigen-antibody immunocomplex. The proposed immunosensor demonstrated a broad concentration range of 0.01 to 30 ng mL-1 with a low limit of detection (LOD) of 0.01 ng mL-1. In addition, the present sensor exhibited excellent selectivity, reproducibility, and long-term stability, suggesting its potential use to determine CEA in clinical immunoassay.Copyright © 2023 Elsevier B.V. All rights reserved.