Streptavidin-functionalized-polyethyleneimine/chitosan/HfO2-Pr6O11 nanocomposite using label-free electrochemical immunosensor for detecting the hunger hormone ghrelin

Abstract

We report the hydrothermal synthesis of the bimetal oxide hafnium oxide-praseodymium oxide nanoflakes (HfO 2 -Pr 6 O 11 ) incorporated with chitosan (CS) and polyethyleneimine (PEI) to produce a PEI/CS/HfO 2 -Pr 6 O 11 nanocomposite. The negative charge of HfO 2 -Pr 6 O 11 and the positive charge of PEI interact electrostatically in the PEI/CS/HfO 2 -Pr 6 O 11 nanocomposite. The reported nanocomposites exhibit distinct attributes, including high electrical conductivity and surface area, more accessible active sites, and good hydrophilicity. In addition, streptavidin (Strep)-functionalized PEI/CS/HfO 2 -Pr 6 O 11 nanomaterials improved the antibody loading efficiency on the biosensing platform, and certified the protein immobilization activity. The Strep/PEI/CS/HfO 2 -Pr 6 O 11 composites were analyzed using various characterization techniques for use as a label-free electrochemical immunosensor of the hunger hormone ghrelin (GHRL). The constructed immunosensor demonstrated linearity over a wide range (0.01 pg/mL–50 ng/mL) and a LOD of 0.006 pg/mL, along with good specificity, precision (reproducibility and repeatability), and cyclic and storage stability for GHRL detection. The practicability of the immunosensor was assessed using serum samples from healthy individuals. • The BSA/anti-GHRL/Strep/PEI/CS/HfO 2 -Pr 6 O 11 /SPE nanocomposite probe was prepared. • The nanocomposite probe was applied to fabricate the ghrelin immunosensor. • The wide linearity with a low LOD of 0.006 pg/mL for ghrelin was achieved. • This ghrelin immunosensor had good specificity with related interfering substances. • In human serum samples, the practical feasibility of ghrelin detection was ensured.