Anti‐Clostridium tetani Antibody Determination in Serum Samples by Amperometric Immunosensing

Abstract

An electrochemical (EC) immunosensing assay for anti-Clostridium tetani antibody determination in serum has been developed. The antigen tetanus toxoid was immobilized on superparamagnetic nanobeads. The immunoreaction occurred in Eppendorf minitubes. The anti-tetani antibody was incubated in the presence of the toxoid functionalized nanobeads, then reacted with horseradish peroxidase-labeled anti-IgG. The resulting immunobeads were retained onto the carbon paste working electrode with a magnet. Hydroquinone served as redox label. The level of antiClostridium tetani antibody in guinea pig serum samples was determined by amperometry using a carbon based screen-printed electrode (cSPE) housed onto a magnetic support. The EC response was proportional to the logarithm of the antibody concentration comprised between 0.0046 IU/mL and 0.175 IU/mL with a limit of detection of 0.0046 IU/mL. In order to minimize the matrix effect, the standard addition method was applied. The assay was validated by comparing the EC immunosensing data with those obtained by applying the ELISA method described in the European Pharmacopoeia.

Rapid Quantitative Detection of Brucella melitensis by a Label-Free Impedance Immunosensor Based on a Gold Nanoparticle-Modified Screen-Printed Carbon Electrode

“…Due to recent developments in biosensor technology, the production of electrochemical transducers using screen-printed carbon electrodes (SPCEs) is well established. Electrochemical immunosensors based on SPCEs challenge the conventional electrochemical biosensors for fabrication, disposability and portability, which make them suitable for working with microvolumes and for decentralized assays (point of care tests) [12]. In particular, the coupling of screen-printed electrodes with metal nanoparticles (such as gold nanoparticles, GNPs) in electrochemical immunosensors has received considerable attention.…”

Magnetic Beads‐Based Electrochemical Sensors Applied to the Detection and Quantification of Bioterrorism/Biohazard Agents

“…They can be summarized as: (1) high reaction kinetics in a small volume, high surface area and high dispersion capability of MBs leading to an increase in surface-to-volume ratio, together with a decrease of matrix effects and, consequently, to a substantial shortening of the immunoreaction times; (2) versatile manipulation and optimization of experimental conditions, as a consequence of the separation between the electrochemical detection and the immunoreaction steps, as it will be illustrated below; (3) less time consuming due to decreased coating, competition and blocking times; (4) modification of MBs in numerous ways allowing different immobilization strategies; and (5) the immunocomplexes formed on the MBs surface can be easily detected without preconcentration or purification steps, which are normally required for standard immunoassays [1,14,15]. In summary, the good analytical performance of the immunodevices using functionalized MBs can be attributed to the increased surface area and reactivity, high effectiveness of blocking reagents, and improved washing and separation steps.…”

“…Interesting examples of these approaches are the electrochemical magnetoimmunosensing assays developed for the rapid, selective and sensitive quantification of anti-Helicobacter pylori [28], anti-Clostridium tetani [14], and anti-hepatitis B virus [29] IgG antibodies. The detection of these antibodies in serum was carried out by indirect antibody capture assays based on the use of purified antigens immobilized on magnetic microspheres.…”

“…The detection of these antibodies in serum was carried out by indirect antibody capture assays based on the use of purified antigens immobilized on magnetic microspheres. The IgG antibodies present in the serum samples were allowed to react immunologically with the immobilized antigens, and the bound antibodies were quantified by enzyme-labelled [14,28] or gold nanoparticles (AuNPs)-conjugated [29] secondary antibodies specific to human IgG. These original approaches may be extended to on site applications dealing with the screening of antibody levels in complex samples.…”