A highly sensitive immunosensor based on {ITO} thin films covered by a new semi-conductive conjugated polymer for the determination of TNF? in human saliva and serum samples

By Ayd?n, Elif Burcu; Ayd?n, Muhammet; Sezgint
Published in Biosensors and Bioelectronics NULL 2017

Abstract

Abstract A novel, ultrasensitive impedimetric immunosensor was constructed for the detection of tumor necrosis factor ? (TNF?) by using Poly(3-thiophene acetic acid) (P3), a conjugated polymer as an immobilization matrix. The polymer {P3} contains a lot of carboxylic acid groups on its surface that provide a larger biorecognition surface. This developed immunosensor was prepared on hydroxy-bearing {ITO} surface via an ester bond linkage of polymer {P3} to immobilize anti-TNF ? antibodies. The {ITO} electrode modification steps and interaction between anti-TNF ? antibody and {TNF} ? antigen were monitored by cyclic voltammetry (CV) and by electrochemical impedance spectroscopy (EIS) method. After the analytical parameters optimization, a linear detection response from 0.01 pg/mL to 2 pg/mL, a limit of detection {LOD} of 3.7 fg/mL and a limit of quantification (LOQ) of 12.4 fg/mL were achieved, which provided accurate results (relative standard deviation; 4.03%). The characterization of this developed immunosensor was performed by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy dispersive X-ray (EDX) mapping and atomic force microscopy (AFM). The immunosensor allowed a simple and fast detection of {TNF} ? antigen in human serum and satisfied recoveries (98.69

Read » Back