Developing of A Novel Clinical Kit for Assaying of Alpha-fetoprotein Based on Luminescent and Magnetic Nanoparticles
Alpha-fetoprotein (α-FP, AFP) was the only serological marker currently available for the detection of hepatocellular carcinoma
(HCC). As a novel biological luminescent label, the favorable properties of water-soluble CdTe quantum dots (QDs) have advantages
over conventional fluorescent materials. Meantime, the magnetic separation technique has widely been applied to various aspects in
biotechnology in recent years. In this paper, CdTe QDs and dextran–Fe3O4 magnetic nanoparticles were both applied on immunoassay for
the determination of AFP concentration. Firstly, a mouse anti-human AFP antibody (primary antibody) was immobilized on magnetic
nanoparticles, which were used as solid support. Secondly, another mouse anti-human AFP antibody (secondary antibody) was attached
to the surface of the CdTe QDs via electrostatic interaction. It was found that when the pH value was 6.0, the volume ratio of CdTe
(3×10-4 mol/L) to antibody (2 mg/mL) was 50:3, and the reaction time was more than 10 min, the complex of the secondary antibody and
CdTe was formed and the strongest PL intensity was obtained. Thirdly, the above two complexes were conjugated with a serial of AFP
concentrations. Then the relationship between the PL intensity and the AFP concentration was determined and the calibration equation
Y=k(X-9.31)/Vwas obtained. Finally, ten samples of human serum were tested based on this equation. The results, to a large extent,
were consistent with those obtained by Time-resolved Fluorescence. More importantly, the current method could be applied in many
other antibody-antigen systems.
Keywords: AFP, CdTe, clinical kit, label, luminescence, magnetic nanoparticles.
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