scholarly journals Fabrication of AuNPs/MWCNTS/Chitosan Nanocomposite for the Electrochemical Aptasensing of Cadmium in Water

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 105
Author(s):  
Selma Rabai ◽  
Ahlem Teniou ◽  
Gaëlle Catanante ◽  
Messaoud Benounis ◽  
Jean-Louis Marty ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Electrochemical Biosensor ◽  
Electrochemical Impedance ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Applied Potential ◽  
Toxic Heavy Metals ◽  
Cadmium Detection ◽  
Interfering Ions

Cadmium (Cd2+) is one of the most toxic heavy metals causing serious health problems; thus, designing accurate analytical methods for monitoring such pollutants is highly urgent. Herein, we report a label-free electrochemical aptasensor for cadmium detection in water. For this, a nanocomposite combining the advantages of gold nanoparticles (AuNPs), carbon nanotubes (CNTs) and chitosan (Cs) was constructed and used as immobilization support for the cadmium aptamer. First, the surface of a glassy carbon electrode (GCE) was modified with CNTs-CS. Then, AuNPs were deposited on CNTs-CS/GCE using chrono-amperometry. Finally, the immobilization of the amino-modified Cd-aptamer was achieved via glutaraldehyde cross-linking. The different synthesis steps of the AuNPs/CNTs/CS nano assembly were characterized by cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) was employed for cadmium determination. The proposed biosensor exhibited excellent performances for cadmium detection at a low applied potential (−0.5 V) with a high sensitivity (1.2 KΩ·M−1), a detection limit of 0.02 pM and a wide linear range (10−13–10−4 M). Moreover, the aptasensor showed a good selectivity against the interfering ions: Pb2+; Hg2+ and Zn2+. Our electrochemical biosensor provides a simple and sensitive approach for Cd2+ detection in aqueous solutions, with promising applications in the monitoring of trace amounts of heavy metals in real samples.

Encapsulation of hemin in Fe-based metal-organic frameworks and its application for the direct determination of aflatoxin M1

2021 ◽  
pp. 1-10
Author(s):  
F. Jahangiri-Dehaghani ◽  
H.R. Zare ◽  
Z. Shekari
Keyword(s):  
Electrochemical Impedance ◽  
Metal Organic Frameworks ◽  
Direct Determination ◽  
Differential Pulse ◽  
Aflatoxin M1 ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Selective Determination ◽  
Metal Organic

A label-free electrochemical aptasensor was constructed for the sensitive and selective determination of AFM1. For preparation of the aptasensor, the AFM1 aptamer was immobilised on the surface of a glassy carbon electrode modified with hemin encapsulated in Fe-based metal-organic frameworks (hemin@Fe-MIL-101). The morphology and the structure of Fe-MIL-101 and hemin@Fe-MIL-101 were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction and Brunauer-Emmett-Teller-N2 sorption methods. Electrochemical impedance spectroscopy and cyclic voltammetry were performed to monitor the fabrication process of the electrochemical aptasensor. The electrochemical reduction current of hemin encapsulated in Fe-MIL-101 serves as a signal for the quantitative determination of AFM1. Differential pulse voltammetry was done to determine the AFM1 concentration in the linear range of 1.0×10-1-100.0 ng/ml. The detection limit of AFM1 was estimated to be 4.6×10-2 ng/ml. Finally, the fabricated aptasensor was applied to determine AFM1 in raw and boiled milk samples.

scholarly journals Rapid Determination of Ochratoxin A in Grape and Its Commodities Based on a Label-Free Impedimetric Aptasensor Constructed by Layer-by-Layer Self-Assembly

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 71 ◽  
Author(s):  
Mina Nan ◽  
Yang Bi ◽  
Huali Xue ◽  
Sulin Xue ◽  
Haitao Long ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Self Assembly ◽  
Electrochemical Impedance ◽  
Rapid Determination ◽  
Grape Juice ◽  
High Sensitivity ◽  
Layer By Layer ◽  
Label Free ◽  
Transfer Resistance

A simple and sensitive label-free impedimetric aptasensor for rapid determination of ochratoxin A (OTA) has been developed, which was based on the combination between thiolated aptamer and gold nanoparticles by layer-by-layer self-assembly. Because of the interaction between aptamer and OTA, the relative normalized electron-transfer resistance (ΔRct) values obtained by electrochemical impedance spectroscopy (EIS) was proportional to the concentration of OTA and showed a good linear relationship from 0.1 to 10.0 ng/mL, with a lower detection limit (0.030 ng/mL) than one-step thiolated DNA aptasensor. The established method was successfully applied to detect and analyze OTA in table wine and grape juice, and the recovery was 90.56%–104.21% when PVP effective removed of phenolic substances. The label-free impedimetric aptasensor was used for rapid detection and quantitation of OTA in the inoculated grapes with the Aspergillus Nigri (H1), and the production of OTA (62.4 μg/kg, 20 μg/kg) far exceeded the maximum levels of 2 μg/kg after inoculation for three days. The developed method exhibited a good specificity, high sensitivity, time-efficient, and it could be applied to detect the OTA concentration in grape and its commodities.

A simple label-free electrochemical aptasensor for dopamine detection

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 52250-52255 ◽  
Author(s):  
Jiawan Zhou ◽  
Wenyang Wang ◽  
Peng Yu ◽  
Erhu Xiong ◽  
Xiaohua Zhang ◽  
...  
Keyword(s):  
Electrochemical Biosensor ◽  
Dna Aptamer ◽  
Selective Detection ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Dopamine Detection

A simple and label-free electrochemical biosensor based on a dopamine DNA aptamer was developed for the sensitive and selective detection of dopamine.

Electrokinetics-Based Microfluidic Technology for the Rapid Separation and Concentration of Bacteria/Cells/Biomolecules

2014 ◽  
Vol 911 ◽  
pp. 347-351 ◽  
Author(s):  
I Fang Cheng ◽  
Tzu Ying Chen ◽  
Hsien Chang Chang
Keyword(s):  
Cancer Cell ◽  
Electrochemical Impedance ◽  
High Sensitivity ◽  
High Specificity ◽  
Cell Detection ◽  
Label Free ◽  
Rapid Separation ◽  
Whole Cells ◽  
Highly Sensitive ◽  
Label Free Detection

Conventional techniques for detection of bacteria/cell and assessment of cancer cell typically use DNA techniques, Western blot and ELISA kits that are high cost, complicated processes and long time consuming. Our researches focus on rapid, portable, simple and highly sensitive separation and detection of cells/bacteria/biomolecules for field-use diagnosis. An ideal portable biosensor (molecular or whole cells detections) unit must have several important features: rapid detection time (<10 minutes), high sensitivity (pM level for molecular detection, 103 cells/ml for whole cell detection), high specificity, small and inexpensive instrumentation configuration. Electrochemical impedance/conductance sensing is preferred over optical detection because of cost and portability concerns. Cancer cell detection using heterogeneous medical samples require continuous isolation, sorting, and trapping of the target bioparticles and immunocolloids within a diagnostic chip. We have developed several electrokinetic strategies to rapid separation, concentration and detection of cells/bacteria/biomolecules in a microfluidic chip using such as dielectrophoresis (DEP), traveling-wave dielectrophoresis (twDEP) and electrohydrodynamics (EHD). Several key techniques we done, which on a rapid/simple/label-free detection platform for the highly sensitive on-chip separation/identification/quantification will be introduced in this paper.

scholarly journals Highly Sensitive Electrochemical Aptasensor for Detecting the VEGF165 Tumor Marker with PANI/CNT Nanocomposites

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 114
Author(s):  
Yunjeong Park ◽  
Min-Sung Hong ◽  
Woo-Hyuk Lee ◽  
Jung-Gu Kim ◽  
Kyunghoon Kim
Keyword(s):  
Tumor Marker ◽  
Limit Of Detection ◽  
Biological Fluid ◽  
Low Cost ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Promising Tool ◽  
Highly Sensitive ◽  
Endothelial Growth Factor

Sensing targeted tumor markers with high sensitivity provides vital information for the fast diagnosis and treatment of cancer patients. A vascular endothelial growth factor (VEGF165) have recently emerged as a promising biomarker of tumor cells. The electrochemical aptasensor is a promising tool for detecting VEGF165 because of its advantages such as a low cost and quantitative analysis. To produce a sensitive and stable sensor electrode, nanocomposites based on polyaniline (PANI) and carbon nanotube (CNT) have potential, as they provide for easy fabrication, simple synthesis, have a large surface area, and are suitable in biological environments. Here, a label-free electrochemical aptasensor based on nanocomposites of CNT and PANI was prepared for detecting VEGF165 as a tumor marker. The nanocomposite was assembled with immobilized VEGF165 aptamer as a highly sensitive VEGF165 sensor. It exhibited stable and wide linear detection ranges from 0.5 pg/mL to 1 μg/mL, with a limit of detection of 0.4 pg/mL because of the complementary effect of PANI/CNT. The fabricated aptasensor also exhibited good stability in biological conditions, selectivity, and reproducibility after several measurement times after the dissociation process. Thus, it could be applied for the non-invasive determination of VEGF, in biological fluid diagnosis kits, or in an aptamer-based biosensor platform in the near future.

scholarly journals A SARS-CoV-2 aptasensor based on electrochemical impedance spectroscopy and low-cost gold electrode substrates.

2021 ◽  
Author(s):  
Perrine Lasserre ◽  
Banushan Balansethupathy ◽  
Vincent J. Vezza ◽  
Adrian Butterworth ◽  
Alexander MacDonald ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Low Cost ◽  
Glucose Monitoring ◽  
High Sensitivity ◽  
Blood Glucose Monitoring ◽  
Label Free ◽  
Rna Sequences ◽  
Point Of Use ◽  
Lateral Flow Assays ◽  
Impedimetric Biosensor

SARS-CoV-2 diagnostic practices broadly involve either qPCR based nucleic amplification or lateral flow assays (LFAs). qPCR based techniques suffer from the disadvantage of requiring thermal cycling (difficult to implement for low-cost field use) leading to limitation on sample to answer time, the potential to amplify viral RNA sequences after a person is no longer infectious and being reagent intense. LFA performance is restricted by qualitative or semi-quantitative readouts, limits on sensitivity and poor reproducibility. Electrochemical biosensors, and particularly glucose test strips, present an appealing platform for development of biosensing solutions for SARS-CoV-2 as they can be multiplexed and implemented at very low cost at point of use with high sensitivity and quantitative digital readout. This work reports the successful raising of an Opti-mer sequence for the spike protein of SARS-CoV-2 and then development of an impedimetric biosensor which utilises thin film gold sensors on low-cost laminate substrates from home blood glucose monitoring. Clinically relevant detection levels for SARS-CoV-2 are achieved in a simple, label-free measurement format using sample incubation times of 15 minutes. The biosensor developed here is compatible with mass manufacture, is sensitive and low-cost CE marked readout instruments already exist. These findings pave the way to a low cost and mass manufacturable test with the potential to overcome the limitations associated with current technologies.

scholarly journals Development of a label-free electrochemical aptasensor based on diazonium electrodeposition: Application to cadmium detection in water

2021 ◽  
Vol 612 ◽  
pp. 113956
Author(s):  
Selma Rabai ◽  
Messaoud Benounis ◽  
Gaëlle Catanante ◽  
Abdoullatif Baraket ◽  
Abdelhamid Errachid ◽  
...  
Keyword(s):  
Label Free ◽  
Electrochemical Aptasensor ◽  
Cadmium Detection

A novel three-dimensional DNA nanostructure used for thrombin detection

2017 ◽  
Vol 9 (35) ◽  
pp. 5115-5120 ◽  
Author(s):  
Huawei Shu ◽  
He Mei ◽  
Jinxin Gu ◽  
Yongbin Yang ◽  
Baoguang Chen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Dna Nanostructure

In this paper, a label-free electrochemical aptasensor for the detection of thrombin with high sensitivity is proposed.

Fabrication of Electrochemical Biosensor Using Zinc Oxide Nanoflowers for the Detection of Uric Acid

2021 ◽  
Author(s):  
priyanka dutta ◽  
Vikas sharma ◽  
Hema bhardwaj ◽  
ved varun agrawal ◽  
Rajesh nil ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Uric Acid ◽  
Indium Tin Oxide ◽  
Electrochemical Biosensor ◽  
Limit Of Detection ◽  
Hydrothermal Process ◽  
High Sensitivity ◽  
Label Free ◽  
Ir Study

Abstract A label-free electrochemical biosensor has been developed using Zinc Oxide nanoflowers (ZnONFs) for the detection of Uric acid. ZnONFs have been synthesized by hydrothermal process and characterized with several techniques such as Ultraviolet-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR) study, X-ray diffraction study, Raman spectroscopy, Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy (HR-TEM) and electrochemical analyser to confirms the formation of nanoflowers and fabrication of electrode and bioelectrodes for uric acid detection. Pure and uniform needle flowers and deposited onto Indium Tin Oxide (ITO) substrate through electrophoretic deposition technique. Further, electrochemical studies have been performed with immobilized enzymatic bioelectrode followed by various uric acid concentrations. It has been found that the fabricated biosensor shows high sensitivity (10.38 µA/ mg/mL /cm2) and a limit of detection of 0.13 mg/mL in the range of 0.005 to 1.0 mg/mL. This study demonstrates the potential use of ZnONFs for the construction of overly sensitive biosensors for Uric acid detection.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

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