A novel label-free graphene oxide nano-wall surface decorated with gold nano-flower biosensor for electrochemical detection of brucellosis antibodies in human serum

Abstract

Conventional serological methods to detect brucellosis are time-consuming, expensive, and require special equipment, but they are less sensitive than newly developed approaches. To overcome these drawbacks, in addition to the ultrasensitive, rapid, easy, and early detection of brucellosis biomarkers, more emphasis on novel methods through electrochemical nanostructured platforms is needed. A novel nanostructured platform made of graphene oxide (GO) nanosheet and gold nanoparticles (AuNPs), with field emission scanning electron microscopy (FESEM) scanning revealing that the GO is vertically arranged on the surface like nano-walls (GONW) and the AuNPs are decorated in the shape of nanoflowers. FESEM, energy dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) were used to characterize the successfully fabricated nanostructured surface. The electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) techniques applied to the fabricated graphene oxide nanowall-gold nanoflower (GONW@Au-NF) platform indicated excellent electroactivity (more than a 40% increase) and valuable antifouling properties, which make it more sensitive than bare fluorine-doped tin oxide (FTO) electrodes. The limit of detection (LOD) using different concentrations of Brucella–against antibody (Br-Ab) is estimated at 9.3 fg mL−1. The selectivity of the biosensor was tested using E.coli antibody and bovine serum albumin (BSA). The results revealed good selectivity (significant difference) and acceptable reproducibility (not exceeding 12% RSD). Rapid and early detection of Br-Ab in both PBS and real samples (serum), with excellent sensitivity and selectivity, proposed our fabricated biosensor as an ideal candidate for brucellosis biomarker detection.