Mass Spectrometric Bioanalysis Assisted by Noble Metal Nanoparticles - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 285

rabbit anti-human IgG, which was detected using AuNP-labeled
goat-anti-rabbit IgG. After extensive washes, AuNPs were dissociated
from the immunocomplex with HNO 3 solution. The collected eluent
was subsequently delivered to the ICP-MS for the measurement of
elemental Au. An ICP-MS linked immunoassay protocol is illustrated
in Fig. 12.5. Using a similar strategy, Baranov et al . described
an immunoprecipitation method coupled with ICP-MS for the
determination of human IgG. 69 The complexes between human IgG
and its speciic AuNP-modiied antibody were precipitated upon the
addition of protein A-immobilized sepharose beads. Merkocüi et al .
utilized ICP-MS for the immunoassay of peptide-conjugated DNA that
was immobilized onto nitrocellulose membrane. 70 This analyte was
incubated with anti-peptide antibody and then detected by AuNP-
modiied secondary antibody. Compared to a conventional dot-blot
reference method, this ICP-MS-based DNA assay provided a 40-
fold improvement in the LOD for the oligonucleotide. Very recently,
Zhang et al . developed a sandwich-type immunoassay coupled with
ICP-MS for the detection of anti-erythropoietin antibody in serum
sample. 71
Figure 12.5 An ICP-MS-linked immunoassay protocol. Reprinted with
permission from Ref. 68.
Through the combination of AuNP- and Eu 3+ -labeled antibody
with ICP-MS, simultaneous detection of multiple proteins has been
introduced by Quinn et al . 72 It is demonstrated that this method
can provide a linear response to both proteins in the concentration
range of 2−100 ng/mL. Because ICP-MS-linked immunoassay cannot