Label-Free Toxin Detection by Means of Time-Resolved Electrochemical Impedance Spectroscopy

Abstract

The real-time detection of trace concentrations of biological toxins requires significant improvement of the detection methods from those reported in the literature. To develop a highly sensitive and selective detection device it is necessary to determine the optimal measuring conditions for the electrochemical sensor in three domains: time, frequency and polarization potential. In this work we utilized a time-resolved electrochemical impedance spectroscopy for the detection of trace concentrations of Staphylococcus enterotoxin B (SEB). An anti-SEB antibody has been attached to the nano-porous aluminum surface using 3-aminopropyltriethoxysilane/glutaraldehyde coupling system. This immobilization method allows fabrication of a highly reproducible and stable sensing device. Using developed immobilization procedure and optimized detection regime, it is possible to determine the presence of SEB at the levels as low as 10 pg/mL in 15 minutes.

Immobilization of Antibodies and Enzymes on 3-Aminopropyltriethoxysilane-Functionalized Bioanalytical Platforms for Biosensors and Diagnostics

“…Similarly, anti-SEB Ab bound to the APTES-functionalized nanoporous aluminum surface via GLD activation has been described for detection of Staphylococcus enterotoxin B (SEB) as low as 10 pg mL −1 in 15 min. 243 The measurement is based on time-resolved electrochemical impedance spectroscopy (EIS). SPR Au chips can be reused by treatment with 12 M HCl for 10 min and O 2 -plasma scrapping for 5 min.…”

Direct Detection of the Biological Toxin in Acidic Environment by Electrochemical Impedimetric Immunosensor

“…Impedimetric response of EII to the immunoreaction between immobilized Ab on EII and Ag in a diagnostic solution was characterized based on EIS technique [11]. From EIS analysis, we obtained the complex impedance ( Z ), which can be represented as: $Z(t,\hspace{0.17em}\omega )=\frac{V(t,\hspace{0.17em}\omega )}{I(t,\hspace{0.17em}\omega )}=Z_0(t)e^{j\theta }=Z^{\prime }(t,\hspace{0.17em}\omega )+Z^{″}(t,\hspace{0.17em}\omega )$where Z ( t , ω ) is a complex impedance ( Z ) at time ( t ) and radial frequency ( ω ), V is a voltage, I is a current, θ is a phase angle, Z’ is the real part of a complex impedance, and Z” is the imaginary part of the complex impedance.…”

Impedimetric Characterization of Adsorption of Listeria monocytogenes on the Surface of an Aluminum‐Based Immunosensor

“…The resistance of impedance ( R , the real part of impedance) decreases with complexation between human serum albumin and the Ab on the surface of a silicon nitride (Caballero and others ). However, the R value increases with Ab‐Ag formation on the surface of a nanoporous anodic aluminum that was supposed to be electrically conductive (Chai and Takhistov ; Chai and Takhistov ). Thus, in development of an impedimetric immunosensor for detection of food toxins or pathogens, the impedance behavior of the immunosensor according to the electrochemical properties of the substrate has to be characterized in order to distinguish toxin‐ or pathogen‐specific impedimetric signal outputs.…”