Fabrication of an ultrasensitive and single-use graphite paper based immunosensor for Neuropeptide Y detection: A promising biosensing system for early detection of childhood obesity

Abstract

The purpose of this study was to develop a label-free impedimetric immunosensing system as an analysis technique for hypothalamic Neuropeptide Y hormone with the goal of determining childhood obesity. A novel process for producing a bioelectrode modified with reduced graphene oxide and its biocompatibility with neuropeptide Y was discussed. The immobilization process is based on the adsorption of reduced graphene oxide (dispersed in dimethylformamide solution) onto a novel graphite paper electrode. Anti-neuropeptide Y antibodies were covalently immobilized on the reduced graphene oxide modified electrode surface using ethyl(dimethylaminopropyl) carbodiimide / N-Hydroxysuccinimide coupling chemistry. Electrochemical impedance spectroscopy and cyclic voltammetry techniques were used to monitor and evaluate all immobilization stages, optimization studies, and analytical characterization of the biosensor. The scanning electron microscopy was used to observe the surface morphology during the immobilization steps of the biosensor. The applicability of the designed biosensor to real serum samples was evaluated for clinical use. The biosensor demonstrated high sensitivity for determining neuropeptide Y in real serum samples. The developed immunosensor had a large linear range (0.005 pg mL -1 -10 pg mL -1 ) and a low limit of detection for neuropeptide Y antigen (0.11 fg mL -1 ). Additionally, the designed immunosensor demonstrated high repeatability, reproducibility, long storage stability (after the fifth week, up to 87% of initial activity), and reusability (20 times). Immobilization scheme of the Neuropeptide Y biosensor