A highly sensitive fluorescent immunoassay based on avidin-labeled nanocrystals |
| |
Authors: | King-Keung Sin Cangel Pui-Yee Chan Ting-Huen Pang Matthias Seydack Reinhard Renneberg |
| |
Institution: | (1) Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong;(2) 8sens.biognosticAG, Robert Roessle-Strasse 10, 13125 Berlin, Germany |
| |
Abstract: | Nanocrystals of the fluorogenic precursor fluorescein diacetate (FDA) were applied as labels in order to improve on the assay
sensitivity achieved in our previous studies. Each FDA nanocrystal can be converted into ∼2.6×106 fluorescein molecules, which is useful for improving immunoassay sensitivity and limits of detection. NeutrAvidin was simply
adsorbed onto the surface of the FDA nanocrystals, which were coated with distearoylglycerophosphoethanolamine (DSPE) modified
with amino(poly(ethylene glycol))(PEG(2000)-Amine) as an interface for coupling biomolecules. This can be applied to detect
different kinds of analytes that are captured by corresponding biotinylated biomolecules in different bioanalytical applications.
The applicability of the NeutrAvidin-labeled nanocrystals was demonstrated in an immunoassay using the labeled avidin–biotin
technique. Biotinylated antibody and FDA-labeled avidin were applied to the assay sequentially. The performance was compared
with the traditional sandwich-type assay for mouse immunoglobulin G detection. Following the immunoreaction, the nanocrystals
were released by hydrolysis and dissolution instigated by adding a large volume of organic solvent/sodium hydroxide mixture.
The limit of detection was lower (by a factor of 2.5–21) and the sensitivity was (3.5–30-fold) higher than immunoassays using
commercial labeling systems (FITC and peroxidase). This study shows that using fluorescent nanocrystals in combination with
the avidin–biotin technique can enhance assay sensitivity and provide a lower limit of detection without requiring long incubation
times as in enzyme-based labels. |
| |
Keywords: | FDA Avidin NeutrAvidin Biotin Labeled avidin– biotin technique Immunoassay Fluorescent nanocrystals |
本文献已被 PubMed SpringerLink 等数据库收录! |
|