Electrochemical Impedance Immunosensor Based on Three-Dimensionally Ordered Macroporous Gold Film

Abstract

A novel label-free immunosensor for the detection of C-reactive protein (CRP) was developed based on a three-dimensional ordered macroporous (3DOM) gold film modified electrode by using the electrochemical impedance spectroscopy (EIS) technique. The electrode was electrochemically fabricated with an inverted opal template, making the surface area of the 3DOM gold film up to 14.4 times higher than that of a classical bare flat one, characterized by the cyclic voltammetric (CV) technique. The 3DOM gold film which was composed of interconnected gold nanoparticles not only has a good biocompatible microenvironment but also promotes the increase of conductivity and stability. The CRP immunosensor was developed by covalently conjugating CRP antibodies with 3-mercaptopropionic acid (MPA) on the 3DOM gold film electrode. The CRP concentration was measured through the increase of impedance values in the corresponding specific binding of CRP antigen and CRP antibody. The increased electron-transfer resistance (R(et)) values were proportional to the logarithmic value of CRP concentrations in the range of 0.1 to 20 ng mL(-1). The detection of CRP levels in three sera obtained from hospital showed acceptable accuracy.

The Fabrication of Electrochemical Impedance Immunosensor Based on Aldehyde-containing Self-assembled Monolayers for Hepatitis B Surface Antigen Detection

“…To evaluate the electron transfer nature of the modified Au electrode, CV measurements were carried out in 10 mM K 3 [Fe(CN) 6 ]/K 4 [Fe(CN) 6 ] which was used as a redox probe at a scan rate of 50 mV s…”

“…[1][2][3] Traditional methods used in immunoassays such as radioimmunoassay and enzyme-linked immunosorbent assay are highly sensitive. However, radioimmunoassay exposes laboratory workers to a significant safety hazard, while enzyme-linked immunosorbent assay is tedious and time-consuming.…”

Trends and Perspectives in Immunosensors

“…Recent developments in EIS report using alternative electrode materials such as electrically conducting polymers [44,45] and nanoparticles [46,47]. Additionally, electrode geometry has proven important with interdigitated electrode arrays providing improved sensitivity [39,48].…”

A Versatile Environmental Impedimetric Sensor for Ultrasensitive Determination of Persistent Organic Pollutants (POPs) and Highly Toxic Inorganic Ions

“…Recently, EIS technique has been developed for studying the fundamental and applied electrochemistry and materials science, including characterization of materials,8 biosensors in sensing of bacterial, DNA or protein,9 corrosion science,10 fuel cell, and batteries 11. Despite these abroad applications, only a few studies have reported on the electrochemical detection of POPs at μ m level by our group,12 which could not satisfy the demand of environmental science.…”