Voltammetric immunoassay of human IgG based on the release of cadmium(II) from CdS nanocrystals deposited on mesoporous silica nanospheres
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The authors describe a nanocomposite that was obtained by in-situ deposition of CdS nanocrystals on mesoporous silica nanospheres (MSNs), and its use in an electrochemical immunoassay of human immunoglobulin G (HIgG). The MCN/CdS nanocomposite was covalently modified with the antibodies against HIgG and then employed in a voltammetric immunoassay at antibody-functionalized magnetic beads. Through sandwich immunoreaction, the MCN/CdS nanoprobes are quantitatively captured onto the magnetic beads where numerous Cd(II) ions are released in an acidic solution. The Cd(II) can be detected by anodic stripping voltammetry at a typical working potential of −0.78 V (vs. Ag/AgCl). In combination with the high loading of CdS on MSNs, the use of the stripping voltammetric analysis renders the method high sensitivity. A wide linear range varying from 0.01 to 100 ng mL−1 is obtained for HIgG detection with a lower detection limit at 2.9 pg mL−1. In addition, the preparation of the nanoprobe is inexpensive. The magnetic bead-based assay does not require complex manipulations. Therefore, this method is deemed to possess a wide scope in that it may be applied to other immunoassays.
KeywordsImmunosensor Nanoprobe Signal amplification Anodic stripping voltammetry Magnetic beads
This work was financially supported by the National Natural Science Foundation of China (21475033), Science and Technology Foundation for Excellent Creative Research Group of Hubei Provincial Department of Education (T201810), and Open Fund of Hubei Key Laboratory of Pollutant Analysis and Reuse Technology (PA20170207).
Compliance with ethical standards
The authors declare that they have no competing interests.
- 23.Chen L, Chen C, Li R, Li Y, Liu S (2009) CdTe quantum dot functionalized silica nanosphere labels for ultrasensitive detection of biomarker. Chem Commun (19):2670–2672Google Scholar
- 32.Wang J (2005) Stripping analysis at bismuth electrodes: a review. Electroanalysis17:1341–1346Google Scholar