scholarly journals Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Imen Hafaid ◽  
Asma Gallouz ◽  
Walid Mohamed Hassen ◽  
Adnane Abdelghani ◽  
Zina Sassi ◽  
...  
Keyword(s):  
Iron Nanoparticles ◽  
Gold Surface ◽  
Antibody Immobilization ◽  
Label Free ◽  
Antibody Recognition ◽  
Label Free Detection ◽  
Measured Angle ◽  
Sensitivity Improvement ◽  
Antigen Antibody ◽  
Impedimetric Immunosensor

This work has explored the development of impedimetric immunosensors based on magnetic iron nanoparticles (IrNP) functionalized with streptavidin to which a biotinylated FAB part of the antibody has been bound using a biotin-streptavidin interaction. SPR analysis shows a deviation on the measured (angle) during antigen-antibody recognition whereas label free detection using by EIS allows us to monitor variation of polarization resistance. Before detection, layers were analyzed by FTIR and AFM. Compared to immobilization of antibody on bare gold surface using aminodecanethiol SAM, antibody immobilization on nanoparticles permitted to reach lower detection limit: 500 pg/ml instead of 1 ng/ml to in the case of EIS and 300 ng/ml instead of 4.5 μg/ml in the case of SPR. Thus, it permitted to improve the sensitivity: from 257.3 Ω⋅cm2⋅μg−1⋅mlto 1871 Ω⋅cm2⋅μg−1⋅mlin the case of EIS and from0.003°μg−1⋅mlto0.094°μg−1⋅mlin the case of SPR.

scholarly journals Affinity Sensors for the Diagnosis of COVID-19

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 390
Author(s):  
Maryia Drobysh ◽  
Almira Ramanaviciene ◽  
Roman Viter ◽  
Arunas Ramanavicius
Keyword(s):  
Field Effect Transistors ◽  
Resonance Field ◽  
Analytical Signal ◽  
Nucleic Acid Hybridization ◽  
Detection Methods ◽  
Label Free ◽  
Infected People ◽  
Label Free Detection ◽  
Main Instrument ◽  
Antigen Antibody

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proclaimed a global pandemic in March 2020. Reducing the dissemination rate, in particular by tracking the infected people and their contacts, is the main instrument against infection spreading. Therefore, the creation and implementation of fast, reliable and responsive methods suitable for the diagnosis of COVID-19 are required. These needs can be fulfilled using affinity sensors, which differ in applied detection methods and markers that are generating analytical signals. Recently, nucleic acid hybridization, antigen-antibody interaction, and change of reactive oxygen species (ROS) level are mostly used for the generation of analytical signals, which can be accurately measured by electrochemical, optical, surface plasmon resonance, field-effect transistors, and some other methods and transducers. Electrochemical biosensors are the most consistent with the general trend towards, acceleration, and simplification of the bioanalytical process. These biosensors mostly are based on the determination of antigen-antibody interaction and are robust, sensitive, accurate, and sometimes enable label-free detection of an analyte. Along with the specification of biosensors, we also provide a brief overview of generally used testing techniques, and the description of the structure, life cycle and immune host response to SARS-CoV-2, and some deeper details of analytical signal detection principles.

scholarly journals Label-Free Detection of Chondroitin Sulphate Proteoglycan 4 by a Polyaniline/Graphene Nanocomposite Functionalized Impedimetric Immunosensor

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
JingJing Fu ◽  
ZhuanZhuan Shi ◽  
Man Li ◽  
Yangyang Wang ◽  
Ling Yu
Keyword(s):  
Cell Lines ◽  
Chondroitin Sulphate ◽  
Low Cost ◽  
Enzyme Linked Immunosorbent Assay ◽  
Label Free ◽  
Sulphate Proteoglycan ◽  
Chondroitin Sulphate Proteoglycan ◽  
Label Free Detection ◽  
Proteoglycan 4 ◽  
Impedimetric Immunosensor

The chondroitin sulphate proteoglycan 4 (CSPG4), also known as high molecular weight-melanoma associated antigen (HMW-MAA), is a tumor-associated antigen that is expressed in more than 85% of surgically removed melanoma lesions but has restricted distribution in normal tissues. The diagnostic and therapeutic value of CSPG4 drives a need for sensitive and low-cost detection approaches. To this end, we developed a polyaniline/graphene oxide nanocomposite (PANI@GO) that was electrochemically codeposited on indium tin oxide (ITO) electrode. Glutaraldehyde mediated the covalent immobilization of CSPG4 specific antibody mAbD2.8.5 to construct a CSPG4 immunosensor using cell culture media and cell lysate as samples. The fully assembled impedimetric immunosensor was used to detect CSPG4 in CSPG4-positive cell lines M14/CSPG4 and MV3. No impedance signal changes could be observed from CSPG4-negative cell lines M14 and mAbMk2-23 showing the specificity of the CSPG4-impedimetric immunosensor. This low-cost, simple, and label-free analytical method is an alternative to enzyme-linked immunosorbent assay and flow cytometry in screening of CSPG4 in complex biological samples.

Impedimetric immunosensor for the specific label free detection of ciprofloxacin antibiotic

2007 ◽  
Vol 23 (4) ◽  
pp. 549-555 ◽  
Author(s):  
Rodica E. Ionescu ◽  
Nicole Jaffrezic-Renault ◽  
Laurent Bouffier ◽  
Chantal Gondran ◽  
Serge Cosnier ◽  
...  
Keyword(s):  
Label Free ◽  
Label Free Detection ◽  
Impedimetric Immunosensor ◽  
Specific Label
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