Development of a sugar-derived silver nanoparticle-based electrochemical immunosensor for sensitive D-dimer detection

Abstract

D-dimer (DD) is a key marker of coagulation and fibrinolysis activation. Clinicians can make important decisions with the aid of quick analysis and quantification, ideally at the patient's bedside. Electrochemical immunosensors are effective point-of-care technologies to address these issues. Here, we describe the development of a simple electrochemical immunosensor to detect DD. The immunosensor is constructed by electrodeposition of lactose methoxide aniline silver nanoparticles (LMA-AgNPs) on a screen-printed carbon electrode (SPCE). The LMA-AgNP and SPCE/LMA-AgNP were characterized by Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). The electrochemical behavior of the SPCE/LMA-AgNP was examined using electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV). Then, Anti-D-Dimer antibody (Anti-DD) was immobilized on SPCE/LMA-AgNP. Along with the analytical characterization of the SPCE/LMA-AgNP/Anti-DD immunosensor, the linear range for DD, limit of detection (LOD), potential chemical interferences, and real sample applications were also evaluated. The antigen/antibody interaction at various DD concentrations was monitored using DPV. The SPCE/LMA-AgNP/Anti-DD shows a linear response in the DD concentration range of 0.01–1 pg/mL and a LOD of 0.2 fg/mL. In addition, the SPCE/LMA-AgNP/Anti-DD showed excellent specificity and no response to potential interfering substances, for instance urea, insulin, C-reactive protein (CRP), and serum amyloid A (SAA). Eventually, the SPCE/LMA-AgNP/Anti-DD is applied in human serum, which shows good recovery values (97.2 %). The SPCE/LMA-AgNP/Anti-DD can be fabricated cheaply and easily for bedside clinical evaluation.