Open AccessSurface plasmon resonance immunoassay for cortisol determination with a self‐assembling denaturalised bovine serum albumin layer on surface plasmon resonance chip
Author(s) -
Chen Xing,
Zhang Lulu,
Cui Dafu
Publication year - 2016
Publication title -
micro and nano letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.25
H-Index - 31
ISSN - 1750-0443
DOI - 10.1049/mnl.2015.0344
Subject(s) - surface plasmon resonance , bovine serum albumin , immunoassay , dextran , materials science , biosensor , detection limit , analytical chemistry (journal) , chemistry , chromatography , nanotechnology , nanoparticle , antibody , immunology , biology
A surface modification method has been developed to fabricate surface plasmon resonance (SPR) chip for small molecule determination. A novel denaturalised bovine serum albumin (dBSA)‐SPR‐chip was fabricated by a self‐assembling method, while a dextran‐SPR‐chip was prepared by using a traditional method. The surface morphologies of the two chips were investigated by atomic force microscopy technology and their optical properties were characterised by using our home‐made SPR analytical instrument. The surface binding capacity of the dBSA‐SPR‐chip is 2.5 times higher than that of the dextran‐SPR‐chip. On the basis of the experiments of immune reactions between cortisol antibody and cortisol derivative, the sensitivity of the dBSA‐SPR‐chip is much higher than that of the dextran‐SPR‐based SPR‐chip. The antibody concentration was optimised at about 10 µg/ml in order to obtain high sensitivity, which was used in the followed inhibition immunoassays. The lowest detection limit for cortisol is 1 ng/ml with a linear range of 5–100 ng/ml by using the dBSA‐SPR‐chip. These dBSA‐SPR‐chips can also be applied to detect other small molecules based on the indirect inhibitive immunoassay.