An impedimetric immunosensor for highly sensitive detection of IL-8 in human serum and saliva samples: A new surface modification method by 6-phosphonohexanoic acid for biosensing applications


AYDIN E. B. , SEZGİNTÜRK M. K.

ANALYTICAL BIOCHEMISTRY, vol.554, pp.44-52, 2018 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 554
  • Publication Date: 2018
  • Doi Number: 10.1016/j.ab.2018.05.030
  • Journal Name: ANALYTICAL BIOCHEMISTRY
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.44-52
  • Keywords: Interleukin-8, 6-Phosphonohexanoic acid, Indium tin oxide, Electrochemical impedance spectroscopy, Single frequency impedance spectroscopy, ITO-BASED IMMUNOSENSOR, LABEL-FREE, ELECTROCHEMICAL IMMUNOSENSOR, CANCER BIOMARKER, INTERLEUKIN-8, POLYMER, IMMOBILIZATION, DIAGNOSTICS, ELECTRODES, SENSOR

Abstract

In this study, we fabricated a sensitive and label-free impedimetric immunosensor based on 6-phosphonohexanoic acid (PHA) modified ITO electrode for detection of interleukin-8 (IL-8) in human serum and saliva. PHA was first employed to cancer biomarker sensing platform. Anti-IL-8 antibody was used as a biorecognition element and the detection principle of this immunosensor was based on monitoring specific interaction between anti-IL-8 antibody and IL-8 antigen. The morphological characterization of each electrode modification step was analyzed by scanning electron microscopy (SEM), SEM-energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) while electrochemical characterization was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and single frequency impedance (SFI) techniques. Moreover, the antibody immobilization on the electrode surface was proved Fourier-transform infrared spectroscopy (FTIR) and Raman Spectroscopy. This proposed impedimetric immunosensor exhibited good performances with a wide linear in the range from 0.02 pg/mL to 3 pg/mL as well as a relative low detection limit of 6 fg/mL. The impedimetric immunosensor had a good specificity, stability and reproducibility. This study proved that PHA was a suitable interface material to fabricate an electrochemical biosensor.