Porous boron-doped graphitic carbon nitride-based label-free electrochemical immunoassay of vascular endothelial cadherin

Abstract

As a main connecting protein between endothelial cells, vascular endothelial cadherin (CD144) is involved in regulating vascular remodeling and maintaining vascular integrity. It is regarded as a marker of endothelial dysfunction and injury. Quantitative determination of CD144 is of importance in pathology research, diagnosis and treatment of vascular diseases. A label-free electrochemical method for the immunoassay of CD144 was developed in this work. CD144 antibodies were assembled on a glassy carbon electrode modified with porous boron-doped carbon nitride (B-GCN) and gold nanoparticles (AuNPs) in the presence of protein A. The binding of CD144 on the antibody-modified electrode induced serious steric hindrance, inhibiting the diffusion of ferri-/ferrocyanide from the bulk electrolyte to the electrode interface. The change of the differential pulse voltammetric response displayed a linear relationship with the concentration of CD144 between 0.500 and 400 ng mL⁻¹. The new electrochemical sensor showed some good performances including good selectivity, high stability and satisfactory reproducibility. The cellular morphology observation and activity measurement showed that the dysfunction of vascular endothelial cells appeared in the presence of high-content NaCl. The electrochemical analysis reveals a positive correlation between the release amount of CD144 from the dysfunctional cells and the NaCl concentration in the growth medium.