A highly selective electrochemical immunosensor based on conductive carbon black and star PGMA polymer composite material for IL-8 biomarker detection in human serum and saliva.

A new approach to enhance the electrochemical performance of biosensor was attempted by using Super P© carbon black/Star polymer composite material. In this study, we developed an electrochemical IL 8 biosensor by modification with a conductive composite including Super P, polyvinylidene fluoride (PVDF) and star polymer (SPGMA) of disposable ITO electrode surface. The Super P carbon black as carbonaceous material had a high conductivity and was used for the enhancement of electron transfer between electrode surface and electrolyte. Anti-IL 8 antibodies were utilized as biorecognition molecules and bound to epoxy groups of star polymer covalently. The chemical characterization of antibody immobilization on this composite was performed by using Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy. The characterizations of stepwise modification of this immunosensor were performed by electrochemical techniques such as Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Single Frequency Impedance (SFI); and morphological techniques such as Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Several variables that affect the immunosensor performance were optimized. Under optimum conditions, a wide linear range 0.01-3 pg/mL and low detection limit 3.3 fg/mL were obtained. Super P-star polymer composite modified immunosensor was easy, sensitive, cheap and reliable analytical method for IL 8 detection. The applicability of the proposed immunosensor to determine IL 8 in saliva and serum samples were examined. The results of biosensor and Enzyme-linked Immunosorbent Assay (ELISA) kit were in compatible. Consequently, it was concluded that the electrochemical immunosensor offers a potential approach for IL 8 detection in clinical applications.