11-mercaptoundecanoic-acid and methylaniline

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

Topics: Antibodies, Immobilized; Biosensing Techniques; Carcinoembryonic Antigen; Chitosan; Electrochemical Techniques; Gold; Immunoassay; Limit of Detection; Metal Nanoparticles; Reproducibility of Results