One-pot preparation of conducting composite containing abundant amino groups on electrode surface for electrochemical detection of von willebrand factor

Highlights: • GCE/PAA-CS-AuNPs-Cys was prepared by using a one-pot protocol. • The capture of vWF exerted a negative effect on the electrochemical response of PAA. • The sensitive and label-free detection of vWF was realized. • The release of vWF by the oxidation-injured HUVEC-C cells was investigated. A one-pot protocol based on cyclic voltammetric scan was employed to prepare new conducting composite that was abundant in amino groups. The scanning electron microscope, atomic force microscope, X-ray photoelectron spectroscopy and infrared spectrum characterization demonstrate that poly(azure A), gold nanoparticles, chitosan and cysteine were immobilized simultaneously on glassy carbon electrode surface. Von Willebrand factor (vWF) antibody (Ab) was subsequently assembled by using glutaraldehyde to construct the Ab/composite-modified electrode. The capture of vWF could inhibit the charge transfer between the ferri-/ferrocyanide probe and the electrode and exert the negative effect on the electrochemical response of the dye polymer in the conducting composite due to the strong steric hindrance effect. The DPV peak current change before and after the immunoreaction was found to be proportional to the logarithm of the vWF concentration from 0.001 to 100 μg mL⁻¹ with a detection limit of 0.4 ng mL⁻¹. The proposed label-free electrochemical method was employed in the investigation on the release of vWF by oxidation-injured vascular endothelial cells. The experimental results exhibit that the vWF content in growth medium was increased when the oxidation injury of the cells was intensified in the presence of H₂O₂.