Electrochemical detection and characterization of proteins (original) (raw)
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Journal of The Electrochemical Society, 2010
Peanut protein Ara h 1, a common food allergen, has been previously detected at antibody-coated Au electrodes using electrochemical impedance spectroscopy ͑EIS͒ in ideal solutions, free from interfering species. Here, peanut protein Ara h 1 is detected by EIS at antibody-coated Au electrodes in canned soup that is filtered, diluted, and spiked with peanut protein Ara h 1. In this system, the combined strategy of sample dilution and blocking of unreacted surface sites on the Au electrode with bovine serum albumin is sufficient to dramatically reduce nonspecific adsorption. This is demonstrated by a quantitative comparison of the impedance change at two Au electrodes, one coated with the antibody to peanut protein Ara h 1 and the other coated with the antibody to cockroach protein Bla g 1. These results suggest that nonspecific adsorption does not in general limit the utility of biosensors based on EIS.
Using electrophoretic deposition to identify protein charge in biological medium
Journal of Applied Electrochemistry
Protein adsorption is the first step involved in establishing a suitable integration between a biomaterial and host tissue. It is therefore of highest interest to know the electric charge of proteins present in the relevant medium to be able to predict the behaviour of cells on given surfaces. In this study, electrophoretic deposition (EPD) was used as a simple method to identify the charge of proteins present in biological medium. In the model experiment carried out here, EPD was conducted using a biological medium containing 10% fetal calf serum (FCS) and the charge of the protein was determined by examining the migration of the protein in the EPD cell under a certain applied voltage. In addition, the suitability of EPD of proteins to deliver tailored surfaces for enhanced bioactivity or for controlled deposition of protein films on metallic surfaces was explored.
Direct detection of biomolecules by electrochemical impedance measurements
Sensors and Actuators B: Chemical, 1994
Accurate, early, fast diagnosis of many diseases requires the direct detection of biomolecules such as immunospecies. Until now, in situ studies have consisted in analysing capacitance variations or optical properties. In this work, electrochemical impedance measurements at various frequencies have been performed on p-Si/SiO,/polymer/ grafted antibody/solution heterostructures with or without an antigen. The in-phase impedance change appears to be a specific signal correlated to the antibody/antigen binding, This key parameter is consistent with the specificity, reversrbility and kinetics of that interaction. Higb signal sensitivity will allow the direct titration of the antigen and better knowledge of the structural parameters involved in the antibody/antigen interaction. 0925-4005/94/$07.00 0 1994 Elsevier Science S.A. All rights reserved SSDI 0925-4005(93)01165-Z
Electrodes – the challenge in electrical characterization of biological material
Journal of Physics: Conference Series, 2012
Electrodes are an important part of the impedance measurement chain but their influence is often underestimated. Electrochemical reactions or polarization effects, especially for galvanically coupled systems are sometimes completely neglected. The most important features of electrodes to be considered are the geometry with respect to the structure of the material to be tested and the electrochemistry at the electrode surface. Especially drift and corrosion effects may yield misleading results. If applicable, sophisticated electrode systems should be used in order to prevent the distorting influence of electrode polarization, for extending the useful frequency range of the electrodes or for enhancing the signal-to-noise ratio.
Biosensors and Bioelectronics, 2010
An impedance based electrochemical biosensor was designed and fabricated for the detection of various chemical and biological species, with glass as substrate material and gold interdigitated electrodes. A flow cell with inlet and outlet ports for the microfluidic chamber was designed and fabricated using acrylic material with a reservoir volume of 78 l. The feasibility of the fabricated sensor for detecting very low concentration of chemical and biological species was demonstrated. Electrochemical impedance spectroscopy (EIS) was employed as the detection technique. The impedance based response of the two-terminal device revealed a very high sensitivity with low concentrations of mouse monoclonal IgG, sarcosine, cadmium sulphide (CdS) and potassium chloride (KCl) at pico mole levels.
The use of electrochemical impedance spectroscopy for biosensing
Analytical and Bioanalytical Chemistry, 2008
This review introduces the basic concepts and terms associated with impedance and techniques of measuring impedance. The focus of this review is on the application of this transduction method for sensing purposes. Examples of its use in combination with enzymes, antibodies, DNA and with cells will be described. Important fields of application include immune and nucleic acid analysis. Special attention is devoted to the various electrode design and amplification schemes developed for sensitivity enhancement. Electrolyte insulator semiconductor (EIS) structures will be treated separately.
The use of electrochemical impedance spectroscopie for biosensing
Analytical and Bioanalytical Chemistry
This review introduces the basic concepts and terms associated with impedance and techniques of measuring impedance. The focus of this review is on the application of this transduction method for sensing purposes. Examples of its use in combination with enzymes, antibodies, DNA and with cells will be described. Important fields of application include immune and nucleic acid analysis. Special attention is devoted to the various electrode design and amplification schemes developed for sensitivity enhancement. Electrolyte insulator semiconductor (EIS) structures will be treated separately.
A Sensitive Electrochemical Protein Quantification Method
Electroanalysis, 2000
This article presents a sensitive electrochemical method for the quanti®cation of proteins. The assay used the biuret reaction, which is based on the complexation of proteins with copper ions to form a copper-protein complex. In the present approach, once copper ions were complexed with the protein, they were released by an acidic treatment and simultaneously separated by ultracentrifugation from the protein sample. This allowed differential pulse anodic stripping voltammetry (DPASV) of Cu 2 on carbon rotogravure printed electrodes (CARPEs). A nM detection limit for bovine serum albumin (BSA) was found with this method. The kinetics of this assay were tested and it resulted that the total assay can be carried out in 27 min, including incubation, washing steps and detection.