Real-Time Detection of Antigen–Antibody Reactions by Imaging Ellipsometry

2007 ◽  
Vol 60 (9) ◽  
pp. 667 ◽  
Author(s):  
Irina Chamritski ◽  
Mark Clarkson ◽  
Jeff Franklin ◽  
Shi Wei Li
Keyword(s):  
Real Time ◽  
Specific Binding ◽  
Protein A ◽  
Surface Proteins ◽  
Human Antibody ◽  
Label Free ◽  
Time Resolved ◽  
Imaging Ellipsometry ◽  
Antibody Complex ◽  
Antigen Antibody

In the field of proteomics the quantification of the affinity of an antibody to its partners and the evaluation of its specific binding is an important issue. With an imaging ellipsometer the interaction of an antibody with immobilized antigens on a model microarray is observed in a time-resolved and label-free manner. Imaging ellipsometry was developed for real-time monitoring of the biomolecule interaction between an antigen in solution and an antibody immobilized on a silicon surface. Proteins were immobilized by the formation of carboxy-alkyl monolayers on silicon substrates, where a biotin-labelled antibody was immobilized by a biotin–streptavidin linkage. Anti-human IgG bound specifically to human antibody and protein A, similarly anti-goat IgG bound to goat antibody. No binding was observed between anti-rabbit IgG and goat antibody. All stages of the formation of the antigen–antibody complex were imaged by imaging ellipsometry. By monitoring changes in y, the mole fraction θ of the antigen–antibody binding was determined. Immunological reactions of two different antigen–antibody combinations were fitted by the Langmuir adsorption equation, and affinity constants for two reactions were calculated.

scholarly journals Label-Free Optical Biosensing Using Low-Cost Electrospun Polymeric Nanofibers

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 119
Author(s):  
Paula Martínez-Pérez ◽  
Salvador Ponce-Alcántara ◽  
Nieves Murillo ◽  
Ana Pérez-Márquez ◽  
Jon Maudes ◽  
...  
Keyword(s):  
Real Time ◽  
Large Scale ◽  
High Surface ◽  
Protein A ◽  
Volume Ratio ◽  
Polyamide 6 ◽  
Optical Biosensor ◽  
Label Free ◽  
Electrospinning Technique ◽  
Optical Biosensing

Polymeric nanofiber matrices are promising structures to develop biosensing devices due to their easy and affordable large-scale fabrication and their high surface-to-volume ratio. In this work, the suitability of a polyamide 6 nanofiber matrix for the development of a label-free and real-time Fabry–Pérot cavity-based optical biosensor was studied. For such aim, in-flow biofunctionalization of nanofibers with antibodies, bound through a protein A/G layer, and specific biodetection of 10 µg/mL bovine serum albumin (BSA) were carried out. Both processes were successfully monitored via reflectivity measurements in real-time without labels and their reproducibility was demonstrated when different polymeric nanofiber matrices from the same electrospinning batch were employed as transducers. These results demonstrate not only the suitability of correctly biofunctionalized polyamide 6 nanofiber matrices to be employed for real-time and label-free specific biodetection purposes, but also the potential of electrospinning technique to create affordable and easy-to-fabricate at large scale optical transducers with a reproducible performance.

Application of Radioimmunoassay for Detection of Staphylococcal Enterotoxins in Foods

1980 ◽  
Vol 43 (1) ◽  
pp. 68-72 ◽  
Author(s):  
MERLIN S. BERGDOLL ◽  
RAOUL REISER
Keyword(s):  
Solid Phase ◽  
Protein A ◽  
Staphylococcal Enterotoxins ◽  
A Cells ◽  
Low Concentrations ◽  
Antibody Complex ◽  
Chloramine T ◽  
Antigen Antibody

The staphylococcal enterotoxins can be iodinated with chloramine-T, lactoperoxidase or gaseous iodine. Low concentrations of enterotoxin, chloramine-T and 125I are recommended to avoid possible damage to the enterotoxin. The antigen-antibody complex can be separated from the unreacted enterotoxin by antibodies adsorbed onto tubes or bromoacetyl-cellulose or by precipitation of the complex with a second antibody or protein A cells. As little as 1 ng of enterotoxin per gram of food can be detected in food extracts with the solid-phase tube method or by precipitation of the antigen-antibody complex with protein A cells.

scholarly journals Author response: A label-free approach to detect ligand binding to cell surface proteins in real time

2018 ◽  
Author(s):  
Verena Burtscher ◽  
Matej Hotka ◽  
Yang Li ◽  
Michael Freissmuth ◽  
Walter Sandtner
Keyword(s):  
Cell Surface ◽  
Ligand Binding ◽  
Real Time ◽  
Surface Proteins ◽  
Author Response ◽  
Label Free ◽  
Cell Surface Proteins

Real-time determination of carcinoembryonic antigen by using a contactless electrochemical immunosensor

2016 ◽  
Vol 8 (24) ◽  
pp. 4861-4866 ◽  
Author(s):  
Yan Jin ◽  
Hongju Mao ◽  
Qinghui Jin ◽  
Jianlong Zhao
Keyword(s):  
Detection Limit ◽  
Carcinoembryonic Antigen ◽  
Real Time ◽  
Specific Binding ◽  
Electrochemical Immunosensor ◽  
Label Free ◽  
Time Interaction ◽  
Time Determination ◽  
Impedance Immunosensor

A sensitive label-free and contactless impedance immunosensor is developed for the real-time interaction investigation between a cancer biomarker carcinoembryonic antigen (CEA) and its antibody CEA 5909. The immunosensor is proved to have a specific binding process between CEA and CEA 5909 with a detection limit of 100 fg mL−1in PBS.

Nonspecific binding as a source of error in thyrotropin radioimmunoassay with polyethylene glycol as separating agent.

1980 ◽  
Vol 26 (3) ◽  
pp. 487-490 ◽  
Author(s):  
I W Chen ◽  
L Heminger ◽  
H R Maxon ◽  
J Y Tsay
Keyword(s):  
Polyethylene Glycol ◽  
Specific Binding ◽  
Mean Value ◽  
Total Serum Protein ◽  
Total Serum ◽  
Albumin Concentration ◽  
Nonspecific Binding ◽  
Antibody Complex ◽  
The Individual ◽  
Antigen Antibody

Abstract We investigated the effects of nonspecific binding on thyrotropin values obtained by radioimmunoassay in which polyethylene glycol is used as precipitant. Differences in nonspecific binding among individual samples were significant (F-test, p less than 0.001, range 5.5 to 14.1%). Non-specific binding and total serum protein were directly correlated (r = 0.472, n = 59; p less than 0.001). Nonspecific binding increased with increasing concentrations of globulins but showed no relation to albumin concentration. If globulin concentration was less than 15 g/L, precipitation of the antigen—antibody complex by polyethylene glycol was incomplete. The mean value for thyrotropin in sera from 67 healthy subjects was 2.7 (SD 0.3) milli-international units per liter (milli-int. unit/L) without individual serum nonspecific binding correction, significantly (p less than 0.005) higher than that with nonspecific binding correction (1.6, SD 0.1, milli-int. unit/L). Evidently, inter-sample variations in nonspecific binding may cause significant errors under these conditions, which can be minimized by taking into account the individual nonspecific binding of each serum sample.

scholarly journals Label free detection of specific protein binding using a microwave sensor

The Analyst ◽  
2014 ◽  
Vol 139 (21) ◽  
pp. 5335-5338 ◽  
Author(s):  
Marcela Salazar-Alvarez ◽  
Olga Korostynska ◽  
Alex Mason ◽  
Ahmed Al-Shamma'a ◽  
Jakki C. Cooney ◽  
...  
Keyword(s):  
Protein Binding ◽  
Specific Binding ◽  
Protein A ◽  
Specific Protein ◽  
Label Free ◽  
Microwave Sensor ◽  
Label Free Detection

The specific binding of streptavidin to biotinylated protein A was demonstrated using a label free microwave sensor.

scholarly journals Label-free and real-time detection of specific binding of IgG proteins by oblique-incidence reflectivity difference method

2012 ◽  
Vol 57 (22) ◽  
pp. 2898-2900 ◽  
Author(s):  
Yue Sun ◽  
LiPing He ◽  
Jun Dai ◽  
JingYi Wang ◽  
HuiBin Lü ◽  
...  
Keyword(s):  
Real Time ◽  
Difference Method ◽  
Oblique Incidence ◽  
Specific Binding ◽  
Label Free ◽  
Real Time Detection
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