scholarly journals Electrochemical Detection Platform Based on RGO Functionalized with Diazonium Salt for DNA Hybridization

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 39
Author(s):  
Elena A. Chiticaru ◽  
Luisa Pilan ◽  
Mariana Ioniţă
Keyword(s):  
Charge Transfer ◽  
Dna Hybridization ◽  
Electrochemical Impedance ◽  
Diazonium Salt ◽  
Modified Electrodes ◽  
Covalent Immobilization ◽  
Fabrication Process ◽  
Label Free ◽  
Modified Dna ◽  
Electron Transfer Properties

In this paper, we propose an improved electrochemical platform based on graphene for the detection of DNA hybridization. Commercial screen-printed carbon electrodes (SPCEs) were used for this purpose due to their ease of functionalization and miniaturization opportunities. SPCEs were modified with reduced graphene oxide (RGO), offering a suitable surface for further functionalization. Therefore, aryl-carboxyl groups were integrated onto RGO-modified electrodes by electrochemical reduction of the corresponding diazonium salt to provide enough reaction sites for the covalent immobilization of amino-modified DNA probes. Our final goal was to determine the optimum conditions needed to fabricate a simple, label-free RGO-based electrochemical platform to detect the hybridization between two complementary single-stranded DNA molecules. Each modification step in the fabrication process was monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)6]3−/4− as a redox reporter. Although, the diazonium electrografted layer displayed the expected blocking effect of the charge transfer, the next steps in the modification procedure resulted in enhanced electron transfer properties of the electrode interface. We suggest that the improvement in the charge transfer after the DNA hybridization process could be exploited as a prospective sensing feature. The morphological and structural characterization of the modified electrodes performed by scanning electron microscopy (SEM) and Raman spectroscopy, respectively, were used to validate different modification steps in the platform fabrication process.

Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

2019 ◽  
Vol 15 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Hakan Karadeniz ◽  
Arzum Erdem
Keyword(s):  
Detection Limit ◽  
Dna Hybridization ◽  
Lethal Factor ◽  
Modified Electrodes ◽  
Label Free ◽  
Carbon Paste ◽  
Chip Technology ◽  
Anthrax Lethal Factor ◽  
Hybridization Time ◽  
Electrochemical Monitoring

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

Label-free electrochemical impedance sensing of DNA hybridization based on functionalized graphene sheets

2011 ◽  
Vol 47 (6) ◽  
pp. 1743-1745 ◽  
Author(s):  
Yuwei Hu ◽  
Fenghua Li ◽  
Xiaoxue Bai ◽  
Dan Li ◽  
Shucheng Hua ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Electrochemical Impedance ◽  
Graphene Sheets ◽  
Functionalized Graphene ◽  
Label Free ◽  
Impedance Sensing

scholarly journals Development of an Impedimetric Aptasensor for Label Free Detection of Patulin in Apple Juice

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1017 ◽  
Author(s):  
Reem Khan ◽  
Sondes Ben Aissa ◽  
Tauqir Sherazi ◽  
Gaelle Catanante ◽  
Akhtar Hayat ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Apple Juice ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Diazonium Salt ◽  
Specific Interaction ◽  
Quantitative Detection ◽  
Label Free ◽  
Analytical Technique ◽  
Label Free Detection

In the present work, an aptasensing platform was developed for the detection of a carcinogenic mycotoxin termed patulin (PAT) using a label-free approach. The detection was mainly based on a specific interaction of an aptamer immobilized on carbon-based electrode. A long linear spacer of carboxy-amine polyethylene glycol chain (PEG) was chemically grafted on screen-printed carbon electrodes (SPCEs) via diazonium salt in the aptasensor design. The NH2-modified aptamer was then attached covalently to carboxylic acid groups of previously immobilized bifunctional PEG to build a diblock macromolecule. The immobilized diblocked molecules resulted in the formation of long tunnels on a carbon interface, while the aptamer was assumed as the gate of these tunnels. Upon target analyte binding, the gates were assumed to be closed due to conformational changes in the structure of the aptamer, increasing the resistance to the charge transfer. This increase in resistance was measured by electrochemical impedance spectroscopy, the main analytical technique for the quantitative detection of PAT. Encouragingly, a good linear range between 1 and 25 ng was obtained. The limit of detection and limit of quantification was 2.8 ng L−1 and 4.0 ng L−1, respectively. Selectivity of the aptasensor was confirmed with mycotoxins commonly occurring in food. The developed apta-assay was also applied to a real sample, i.e., fresh apple juice spiked with PAT, and toxin recovery up to 99% was observed. The results obtained validated the suitability and selectivity of the developed apta-assay for the identification and quantification of PAT in real food samples.

Green-synthesized gold nanoparticles decorated graphene sheets for label-free electrochemical impedance DNA hybridization biosensing

2011 ◽  
Vol 26 (11) ◽  
pp. 4355-4361 ◽  
Author(s):  
Yuwei Hu ◽  
Shucheng Hua ◽  
Fenghua Li ◽  
Yuanyuan Jiang ◽  
Xiaoxue Bai ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Dna Hybridization ◽  
Electrochemical Impedance ◽  
Graphene Sheets ◽  
Label Free

scholarly journals Label-Free and Redox Markers-Based Electrochemical Aptasensors for Aflatoxin M1 Detection

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4218 ◽  
Author(s):  
Stefanos Karapetis ◽  
Dimitrios Nikolelis ◽  
Tibor Hianik
Keyword(s):  
Comparative Analysis ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Gold Surface ◽  
Fourth Generation ◽  
Aflatoxin M1 ◽  
Dna Aptamers ◽  
Label Free ◽  
First Case ◽  
Modified Dna

We performed a comparative analysis of the sensitivity of aptamer-based biosensors for detection mycotoxin aflatoxin M1 (AFM1) depending on the method of immobilization of DNA aptamers and method of the detection. Label-free electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) for ferrocene labeled neutravidin layers were used for this purpose. Amino-modified DNA aptamers have been immobilized at the surface of polyamidoamine dendrimers (PAMAM) of fourth generation (G4) or biotin-modified aptamers were immobilized at the neutravidin layer chemisorbed at gold surface. In the first case the limit of detection (LOD) has been determined as 8.47 ng/L. In the second approach the LOD was similar 8.62 ng/L, which is below of allowable limits of AFM1 in milk and milk products. The aptasensors were validated in a spiked milk samples with good recovery better than 78%. Comparative analysis of the sensitivity of immuno- and aptasensors was also performed and showed comparable sensitivity.

scholarly journals Semi-analytical dynamic modeling of DNA surface-hybridization via AC Electro-kinetic steering

2020 ◽  
Author(s):  
P. Capaldo ◽  
S. D. Zilio ◽  
V. Torre ◽  
Y. Yang
Keyword(s):  
Electric Fields ◽  
Dna Hybridization ◽  
Electrochemical Impedance ◽  
Dynamic Properties ◽  
Label Free ◽  
Buffer Solution ◽  
Self Assembled Monolayer ◽  
Reliable Determination ◽  
Design And Optimization ◽  
Solid Gold

ABSTRACTThe change in electrical property (capacitance) upon hybridization of the desired ssDNA to a capture probe has been proposed as a promising technology platform in biomedical research and practice. An appropriate mathematical model is needed for understanding and optimizing the process occurring at the electrode/electrolyte interface. It is also informative for examining the forces generated by the AC electric fields on the DNA molecules as well as the suspending buffer solution in the experimental pool. Here, we provide the development, formulation and validation of a semi-analytical model of DNA hybridization with deoxynucleotide molecules chemically tethered to a solid gold electrode. The parameters of the proposed model have been estimated using available experimental data. We demonstrate that the detection limit and specificity of our surface-based genosensor are not only dependent on the probe/target binding affinity, but also on the Self-Assembled Monolayer (SAM) density and on the interfacial electric field. The label-free Electrochemical Impedance Spectroscopy (EIS)-based oligonucleotide biosensor with integrated DC-biased can achieve rapid hybridization, high selectivity and sensitive detection for DNA target samples.SIGNIFICANCEDNA hybridization, wherein strands of DNA form duplex through noncovalent, sequence-specific interactions, is one of the most fundamental processes in biology. Fast and reliable determination of miniature amounts of DNA plays important role in clinical forensic and pharmaceutical applications. Thus, developing a better understanding of the kinetic and dynamic properties of DNA hybridization will help in the elucidation of all mechanisms involved in numerous biochemical processes. Moreover, because DNA hybridization has been widely adapted in biotechnology, its study is invaluable to the development of a range of commercially important processes.To achieve optimal sensitivity with minimum sample size and rapid hybridization, ability to predict the kinetics of hybridization based on the characteristics of the strands is crucial, and hence a computer aided numerical model for the design and optimization of a DNA biosensor has been implemented.

scholarly journals Label-free hairpin-like aptamer and EIS-based practical, biostable sensor for acetamiprid detection

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244297
Author(s):  
Jianhui Zhen ◽  
Gang Liang ◽  
Ruichun Chen ◽  
Wenshen Jia
Keyword(s):  
Charge Transfer ◽  
Orange Juice ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Charge Transfer Resistance ◽  
Electrochemical Sensing ◽  
Label Free ◽  
Human Beings ◽  
Potential Health ◽  
Transfer Resistance

Acetamiprid (ACE) is a kind of broad-spectrum pesticide that has potential health risk to human beings. Aptamers (Ap-DNA (1)) have a great potential as analytical tools for pesticide detection. In this work, a label-free electrochemical sensing assay for ACE determination is presented by electrochemical impedance spectroscopy (EIS). And the specific binding model between ACE and Ap-DNA (1) was further investigated for the first time. Circular dichroism (CD) spectroscopy and EIS demonstrated that the single strand AP-DNA (1) first formed a loosely secondary structure in Tris-HClO4 (20 mM, pH = 7.4), and then transformed into a more stable hairpin-like structure when incubated in binding buffer (B-buffer). The formed stem-loop bulge provides the specific capturing sites for ACE, forming ACE/AP-DNA (1) complex, and induced the RCT (charge transfer resistance) increase between the solution-based redox probe [Fe(CN)6]3−/4− and the electrode surface. The change of ΔRCT (charge transfer resistance change, ΔRCT = RCT(after)-RCT(before)) is positively related to the ACE level. As a result, the AP-DNA (1) biosensor showed a high sensitivity with the ACE concentration range spanning from 5 nM to 200 mM and a detection limit of 1 nM. The impedimetric AP-DNA (1) sensor also showed good selectivity to ACE over other selected pesticides and exhbited excellent performance in environmental water and orange juice samples analysis, with spiked recoveries in the range of 85.8% to 93.4% in lake water and 83.7% to 89.4% in orange juice. With good performance characteristics of practicality, sensitivity and selectivity, the AP-DNA (1) sensor holds a promising application for the on-site ACE detection.

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