An Electrochemically Reduced Graphene Oxide-Based Electrochemical Immunosensing Platform for Ultrasensitive Antigen Detection

Abstract

We present an electrochemically reduced graphene oxide (ERGO)-based electrochemical immunosensing platform for the ultrasensitive detection of an antigen by the sandwich enzyme-linked immunosorbent assay (ELISA) protocol. Graphene oxide (GO) sheets were initially deposited on the amine-terminated benzenediazonium-modified indiun tin oxide (ITO) surfaces through both electrostatic and π-π interactions between the modified surfaces and GO. This deposition was followed by the electrochemical reduction of graphene oxide (GO) for preparing ERGO-modified ITO surfaces. These surfaces were then coated with an N-acryloxysuccinimide-activated amphiphilic polymer, poly(BMA-r-PEGMA-r-NAS), through π-π stacking interactions between the benzene ring tethered to the polymer and ERGO. After covalent immobilization of a primary antibody on the polymer-modified surfaces, sandwich ELISA was carried out for the detection of an antigen by use of a horseradish peroxidase (HRP)-labeled secondary antibody. Under the optimized experimental conditions, the developed electrochemical immunosensor exhibited a linear response over a wide range of antigen concentrations with a very low limit of detection (ca. 100 fg/mL, which corresponds to ca. 700 aM). The high sensitivity of the electrochemical immunosensor may be attributed not only to the enhanced electrocatalytic activity owing to ERGO but also to the minimized background current owing to the reduced nonspecific binding of proteins.

Three-Dimensional Graphene Interconnected Structure, Fabrication Methods and Applications: Review

“…Over and above this, self-assembly of GO has also been achieved through electrochemical reduction (ErGO) [43][44][45][46][47]. This is more often than not used to directly fabricate electrodes.…”

Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

“…1 A number of well-established methods such as spectroscopic, colorimetric, and chromatographic techniques have been widely used for urea detection. [2][3][4] However, tedious sample preparation restricts their applicability for rapid on-site monitoring.…”

Effect of Different Pretreatments on Indium-Tin Oxide Electrodes

“…Higher electrocatalytic activities can be obtained by modifying ITO electrodes with more electrocatalytic materials such as gold nanoparticles, 22 carbon nanotubes, 23 and graphenes. 24 However, it would be better to obtain higher electrocatalytic activities via simple pretreatment of ITO electrodes. When electrochemical measurements are carried out at potentials below 0 V vs Ag/AgCl, the background currents caused by oxygen reduction reaction are problematic.…”