Preliminary studies of application of CdTe nanocrystals and dextran-Fe3O4 magnetic nanoparticles in sandwich immunoassay.
BACKGROUND
The favorable properties of water-soluble CdTe nanocrystals as novel biological luminescent label over conventional fluorescent probes have attracted considerable interest. The magnetic separation technique has widely been applied to various aspects in biotechnology in recent years. In this paper, we made use of CdTe nanocrystals and dextran-Fe3O4 magnetic nanoparticles for fluorescence immunoassay.


METHODS
The CdTe nanocrystals and dextran-Fe3O4 magnetic nanoparticles were applied to immunoassay for the determination of human immunoglobulin G (HIgG). A rabbit anti-HIgG antibody (primary antibody) was immobilized on magnetic nanoparticles, which was used as a solid support. A sheep anti-HIgG antibody (secondary antibody) was attached to the surface of the CdTe nanocrystals via electrostatic interaction. The immunoassay was based on a sandwich immunoreaction of primary antibody on the magnetic nanoparticles, HIgG (or serum sample), and the secondary antibody labeled with CdTe nanocrystals.


RESULTS
The CdTe label was compared with a fluorescein isothiocyanate (FITC) label. The CdTe is an order of magnitude more sensitive than the FITC. The immunoassay method was applied to determining the HIgG in practical samples and the results obtained are in good agreement with those obtained by nephelometry.


CONCLUSIONS
This technique may be applied in many types of antibody-antigen system.
Li
Xiaozhou
X
College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, PR China.
Wang
Lin
L
Zhou
Chi
C
Guan
Tingting
T
Li
Juan
J
Zhang
Yihua
Y
D000818:Animals; D002104:Cadmium; D002138:Calibration; D003911:Dextrans; D052203:Ferrosoferric Oxide; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G / Q000097:blood*; D053758:Nanoparticles; D012756:Sheep; D013691:Tellurium
D003911:Dextrans; D007074:Immunoglobulin G; D002104:Cadmium; D013691:Tellurium; D052203:Ferrosoferric Oxide