Impedimetric aptasensor for lysozyme detection based on carbon nanofibres enriched screen-printed electrodes

Abstract

In this study, lysozyme (LYS) detection was realized by impedimetric aptasensor that consist of aptamer immobilized carbon nanofibres modified screen printed electrodes (CNF-SPEs). Under this aim, NH2-functionalized LYS-specific aptamer was immobilized to surface of CNF-SPEs via passive adsorption. The step-by-step fabrication process of the aptasensor and the detection of LYS was performed. During the aptasensor fabrication primarily electrochemical characterization was done via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Aptamer-LYS complex formation caused prevention of electron transfer reaction on the interface and thus charge transfer resistance (Rct) increased. Based on this phenomenon, LYS could be quantitatively detected in accordance with the change at Rct values obtained by EIS in the presence of [Fe(CN)6]3–/4– while increasing LYS concentration. Under optimum conditions, the detection limit of the aptasensor was found to be 0.36 µg/mL. The proposed aptasensor was also used for the determination of LYS in fetal bovine serum samples with a detection limit of 1.89 µg/mL. Our assay in combination with the eight-channel array of electrodes was also used for LYS detection to present its implementation to nucleic acid-based array system.