A label-free electrochemical immunosensor based on 11-mercaptoundecanoic acid grafted chitosan and poly(N-methylaniline) for the detection of carcinoembryonic antigen

• Published in: Bioelectrochemistry (Amsterdam, Netherlands) Netherlands), 2023-08, Vol.152, p.108446-108446, Article 108446
• Main Authors: Direksilp, Chatrawee, Parinyanitikul, Napa, Ariyasajjamongkol, Nuttha, Sirivat, Anuvat
• Format: Article
• Language: English
• Subjects: Antibodies, Immobilized - chemistry; Biosensing Techniques - methods; Carcinoembryonic Antigen; Chitosan - chemistry; Electrochemical Techniques - methods; Gold - chemistry; Immunoassay - methods; Label-free electrochemical immunosensor; Limit of Detection; Metal Nanoparticles - chemistry; poly(N-methylaniline); Reproducibility of Results; Thiolated chitosan
• ISSN: 1567-5394; 1878-562X
• DOI: 10.1016/j.bioelechem.2023.108446

[Display omitted] •The label-free CEA immunosensor was fabricated from the tCHI-dPNMA.•MUA was used as a grafting agent for the preparation of tCHI.•tCHI was utilized for anti-CEA immobilization, which was compared to CHI.•The immunosensor based on tCHI/dPNMA presented a wide detectable CEA concentration. 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.