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Abstract
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A novel electrochemical immunosensor was developed for ultrasensitive determination of the hormone insulinlike
growth factor 1 (IGF-1) based on immobilization of a specific monoclonal antibody on the electrospun
nanofibers of Polyacrylonitrile (PAN)/Zein-reduced graphene oxide (rGO) nanoparticle. The nanofibers deposited
on glassy carbon electrode (GCE) showed good electrochemical behaviors with synergistic effects between
PAN, Zein, and rGO. PAN/Zein nanofibers were used due to flexibility, high porosity, good mechanical strength,
high specific surface area, and flexible structures, while rGO nanoparticles were used to improve the detection
sensitivity and anti-IGF-1 immobilizing. Different characterization techniques were applied consisting of FESEM,
FT-IR, and EDS for the investigation of morphological features and nanofiber size. The redox reactions
of [Fe(CN)6]4- /3- on the modified electrode surface were probed for studying the immobilization and determination
processes, using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Under optimal
conditions, LOD (limit of detection) and LOQ (limit of quantification) were obtained as 55.72 fg/mL and 185.73
fg/mL respectively, and sensitivity was acquired 136.29 μA/cm2.dec. Moreover, a wide linear range was obtained
ranging from 1 pg/mL to 10 ng/mL for IGF-1. Furthermore, the proposed method was applied for the
analysis of IGF-1 in several human plasma samples with acceptable results, and it also exhibited high selectivity,
stability, and reproducibility.
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