Матеrial Science" "Nonequilibrium Phase Transformations" 11-14 September, 2017, Varna, Bulgaria Nanogold-Reduced Graphene Oxide Hybrid Nanomaterial Based Electrochemical Immunosensor for Brettanomyces Bruxellensis (original) (raw)
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Iranian Journal of Medical Microbiology
Background and Aim: Escherichia coli (E.coli) is an essential bacterial indicator in the control of pharmaceutical quality and other similar fields. There are some biosensors designed for its detection based on electrochemical transduction methods. A biosensor with reduced graphene oxide was modified. Traditional methods are time-consuming and high prices, so in this study a new biosensor with modification of reduced graphene oxide (rGO) as a kind of carbon composition on glassy carbon electrode (GCE) with Au Nanoparticles (Au NPs) decoration was used for E. coli detection. Materials and Methods: Reduced graphene oxide (rGO) modified on glassy carbon electrode (GCE) and chronoamperometric and reduction methods were used for Au NPs decoration and it was completed with polyclonal E. coli antibody and 0.5 W/V% Bovine Serum Albumin (BSA) solution. Morphology and structure of rGO and Au NPs in GCE/rGO/Au NPs/ E. coli polyclonal antibody/ BSA biosensor were verified by SEM (Scanning Electron Microscope) during modification steps. E. coli detection in dissimilar samples was performed by Square-Wave Voltammetry (SWV) and Cyclic Voltammetry (CV) techniques which were set in 0.1M phosphate buffer solution (PBS) (pH 7.4) mixed with 0.5mM acetaminophen. In comparison with the biosensor, the classical method of detection was performed with serial dilutions of E. coli ATCC 8739 (1×10 1-1×10 8 CFU/mL) which was cultured on media. Results: Despite the two methods used to stabilize Au NPs, scanning electron microscope (SEM) images showed that the current difference did not increase due to gold particles. Its modification had no significant change in current and it was not a successful experiment for E.coli detection. Conclusion: Compared with the plate method, biosensors couldn't substitute with conventional methods for E. coli detection.
Advances in Nanomaterials-Based Electrochemical Biosensors for Foodborne Pathogen Detection
Nanomaterials
Electrochemical biosensors utilizing nanomaterials have received widespread attention in pathogen detection and monitoring. Here, the potential of different nanomaterials and electrochemical technologies is reviewed for the development of novel diagnostic devices for the detection of foodborne pathogens and their biomarkers. The overview covers basic electrochemical methods and means for electrode functionalization, utilization of nanomaterials that include quantum dots, gold, silver and magnetic nanoparticles, carbon nanomaterials (carbon and graphene quantum dots, carbon nanotubes, graphene and reduced graphene oxide, graphene nanoplatelets, laser-induced graphene), metal oxides (nanoparticles, 2D and 3D nanostructures) and other 2D nanomaterials. Moreover, the current and future landscape of synergic effects of nanocomposites combining different nanomaterials is provided to illustrate how the limitations of traditional technologies can be overcome to design rapid, ultrasensitive,...
Biosensors and Bioelectronics, 2006
The design of a new tyrosinase biosensor with improved stability and sensitivity is reported. The biosensor design is based on the construction of a graphite-Teflon composite electrode matrix in which the enzyme and colloidal gold nanoparticles are incorporated by simple physical inclusion. Experimental variables such as the colloidal gold loading into the composite matrix, the enzyme loading and the potential applied to the bioelectrode were optimized. The Tyr-Au coll-graphite-Teflon biosensor exhibited suitable amperometric responses at −0.10 V for the different phenolic compounds tested (catechol; phenol; 3,4-dimethylphenol; 4-chloro-3-methylphenol; 4-chlorophenol; 4chloro-2-methylphenol; 3-methylphenol and 4-methylphenol). The limits of detection obtained were 3 nM for catechol, 3.3 M for 4-chloro-2-methylphenol, and approximately 20 nM for the rest of phenolic compounds. The presence of colloidal gold into the composite matrix gives rise to enhanced kinetics of both the enzyme reaction and the electrochemical reduction of the corresponding o-quinones at the electrode surface, thus allowing the achievement of a high sensitivity. The biosensor exhibited an excellent renewability by simple polishing, with a lifetime of at least 39 days without apparent loss of the immobilized enzyme activity. The usefulness of the biosensor for the analysis of real samples was evaluated by performing the estimation of the content of phenolic compounds in water samples of different characteristics.
Label-free electrochemical immunosensor based on graphene/methylene blue nanocomposite
For the specificity of prostate cancer markers, protsate specific antigen (PSA) has been widely used in prostate cancer screening, diagnosis, and treatment after monitoring. In normal male serum, PSA can only be detected in traces of 0-4 ng mL À1. In this paper, we constructed an electrochemical immunosensor for PSA detection using a nanocomposite film of graphene sheets-methylene blue-chitosan (GS-MB-CS) as electrode material. The nanocomposite film showed high binding affinity to the electrode and was used to immobilize the antibody of PSA. The modification procedure was monitored by cyclic voltammetry (CV). An amperometric biosensor was easily developed based on the response of peak current to the capture of PSA induced by specific antigen-antibody reactions. Under optimum conditions, the amperomet-ric signal decreased linearly with PSA concentration (0.05-5.00 ng mL À1). A low limit of detection (13 pg mL À1) and a high selectivity are obtained. Moreover, the prepared immunosensor was applied for the analysis of PSA in serum samples with satisfactory results. The proposed method may have a promising future in biochemical assays for high selectivity, good reproducibility, and stability. Ó 2012 Elsevier Inc. All rights reserved. Immunosensors are often used to detect or quantify disease-related substances known as biomarkers in clinical diagnostics. Antibodies are immobilized onto the immunosensor surface to capture specific biomarkers [1]. Challenges remain, however, pertaining to the development of simple analysis systems which are cost-effective and robust enough for clinical use. Many kinds of immunosensors such as electrochemistry [2-4], chemilumines-cence [5,6], fluorescence [7-9], piezoelectricity [10], impedance biosensing chips [11], and multichannel microchips [12] have been developed. Therein, electrochemical immunosensors are widely used because of their simple preparation, fast detection, high sensitivity, and low cost. Many micro-and nanomaterials have been used as signal amplifiers in high-performance protein detection platforms [13-19], including gold nanoparticles [20-23], quantum dots [24,25], magnetic nanoparticles [26,27], and carbon nanotubes [28-30]. Compared with these materials, graphene sheets (GS) 1 are considered as an excellent support material due to their high surface area, remarkable mechanical stiffness, and excellent conductivity [31]. Thus, GS have been shown to have fascinating applications in bio-electronics and biosensing [32,33]. It is of paramount importance for immobilizing antibody fragments on the sensor substrate surface without decreasing their binding affinities and binding capacities. For the physical adsorp-tion method, antibody fragments are randomly immobilized with the sensor substrate, mainly through hydrophobic and hydrophilic interactions. Also the orientation of the antibody (Ab) on the sensor substrate surface cannot be controlled. Therefore, the Ab loses its binding activity to the target molecules. For the covalent cross-linking method, the free amino groups on the Ab can be randomly coupled with several reactive moieties on the sensor substrate surface. As a result, the orientation of the immobilized Ab is also random. Thus, there is an increasing need for a technique of achieving well-oriented immobilization of Abs in a small area without decreasing their binding affinity for target molecules, especially for miniaturized diagnostic devices. In order to achieve well-oriented immobilization of antibody, chitosan (CS) was chosen as dispersant to prepare a graphene sheet-methylene blue (GS-MB) nanocomposite. The resultant nanocomposite solution was dropped onto the glassy carbon electrode surface and formed a stable film rich in aminos and hydroxyls.
Detection of Microorganisms Using Graphene-Based Nanobiosensors
Food Technology and Biotechnology, 2021
Having an insight into graphene and graphene derivatives such as graphene oxide, reduced graphene oxide and graphene quantum dots is necessary since it can help scientists to detect possible properties and features that could be useful when using these carbon materials in preparation of a nanocomposites. In recent years, graphene and its derivatives have attracted a lot of attention and been extensively applied in biosensors due to fascinating properties, such as large surface area, optical and magnetic properties, and high elasticity for the detection of microorganisms as they can be modified with some other materials such as macromolecules, oxide metals and metals to improve the electrochemical behaviour of the biosensor. In this review paper, biosensor design strategies based on graphene and its derivatives (graphene-based nanocomposites in biosensors) are described. Then their application for the detection of microorganisms including prions, viroids, viral and bacterial cells as...
Electrochemical Biosensor for Detection of Bioagents
International Journal of Electrochemical Science, 2011
Simple and rapid detection and identification of dangerous bioagents is important for preventing illness or even death of people due to infectious diseases and bioterrorist threats. Electrochemical detection has a large potential for development of portable instrumentation suitable for analysis in field and especially combination with specificity of immunoassays seems promising. Initially, the construction of the immunosensing layer was realised and the effect of Au nanoparticles on the response of peroxidase was studied. An amperometric immunosensor was developed using screen-printed transducer, it employed specific capture of microbes in the sensing area by formation of an immunocomplex and its subsequent labelling using the tracer - antibody conjugated to peroxidase. The obtained sandwich electrochemical immunoassay was applied for the model microbial cells of B. subtilis. The total time of analysis was 20 min and the detection of cells below 104 CFU/ml was feasible. The presence...
International Journal of Food Properties, 2017
Aspergillus flavus detection and the removal of contaminated pistachio are critically important. In this work, an impedimetric electrochemical DNA sensor using gold nanoparticles on the glassy carbon electrode was developed for the sensitive detection of the aflD gene of A. flavus. This biosensor had a linear range of the detection, which was from 1 nM to 10 µM with the detection limit of 0.55 nM, while the best time for hybridization was 4 hr. Results for the detection and reproducibility of the synthetic 21-nucleotide target and the target 76-nucleotide polymerase chain reaction product were the same due to the sensitivity of measurement. In addition, this biosensor can be used to enumerate A. flavus up to 2.5 × 10 8 spores/mL.