Multiplex
biomolecular analysis with inductively coupled plasma
mass spectrometry (ICP-MS) becomes increasingly important in clinical
diagnosis and single cell analysis. However, the sensitivity of ICP-MS-based
immunoassay is only comparable or lower than those of fluorescence
methods at the present stage. Therefore, designing elemental tags
with a large number of metal atoms is necessary to achieve high-sensitive
detection. In this work, we proposed a new strategy to build up elemental
tag loading with hundreds of rare earth ions by coupling alkyne-DNA
chains with rare earth element (REE)-DOTA complexes a click chemistry
reaction. There are about 2 orders of magnitude improvement in sensitivity
compared with single metal-ion tags. DNA chains with multialkynyl
groups were facilely prepared by PCR synthesis. Moreover, the DNA-based
elemental tags own excellent water-solubility and biocompatibility.
The tags would be potentially applied to mass cytometry and clinical
diagnosis.
A combinatorial immunoassay method for biomarker detection based on a stable isotope tagging strategy was proposed. A multiplex immunoassay of 12 proteins could be achieved simultaneously and a combinatorial immunoassay was explored, which would be expected to satisfy the requirements of personalized detection.
The tool box of site-specific cleavage
for nucleic acid has been
an increasingly attractive subject. Especially, the recent emergence
of the orthogonally activatable DNA device is closely related to the
site-specific scission. However, most of these cleavage strategies
are based on exogenous assistance, such as laser irradiation. Endogenous
strategies are highly desirable for the orthogonally regulatable DNA
machine to explore the crucial intracellular biological process and
cell signal network. Here, we found that the accurate site-specific
cleavage reaction of phosphorothioate (PT) modified DNA by using myeloperoxidase
(MPO). A scissors-like mechanism by which MPO breaks PT modification
through chloride oxidation has been revealed. Furthermore, we have
successfully applied the scissors to activate PT-modified hairpin-DNA
machines to produce horseradish peroxidase (HRP)-mimicking DNAzyme
or initiate hybridization chain reaction (HCR) amplification. Since
MPO plays an important role in the pathway related to oxidative stress
in cells, through the HCR amplification activated by this tool box,
the oxidative stress in living cells has been robustly imaged. This
work proposes an accurate and endogenous site-specific cleavage tool
for the research of biostimuli and the construction of DNA molecular
devices.
Objectives
In this study, a new immunoassay for the simultaneous determination of pepsinogen I (PGI) and pepsinogen II (PGII) in serum based on element labeling strategy coupled with inductively coupled plasma mass spectrometry (ICP‐MS) detection was proposed.
Methods
The sandwich‐type immunoassay was used to simultaneously detect PGI and PGII in serum. PGI and PGII were captured by anti‐PGI and anti‐PGII antibody immobilized on the magnetic beads and then banded with Eu
3+
labeled anti‐PGI detection antibody and Sm
3+
labeled anti‐PGII detection antibody, followed by ICP‐MS detection.
Results
The linear correlation coefficient (
R
2
) of PGI and PGII standard curves was .9938 and .9911, with the dynamic range of 0‐200 ng/mL and 0‐60 ng/mL, respectively. The limit of detection for PGI and PGII was 1.8 ng/mL and 0.3 ng/mL, respectively. The average recovery was 101.41% ± 6.74% for PGI and 101.47% ± 4.20% for PGII. Good correlations were obtained between the proposed method and CLIA (
r
= .9588 for PGI,
r
= .9853 for PGII).
Conclusions
We established a mass spectrometry‐based immunoassay for the simultaneous detection of PGI and PGII in a single analysis. The element tagged immunoassay coupled with ICP‐MS detection has high sensitivity, accuracy, and specificity in clinical serum sample analysis.
AbstractIntroductionElement-tagged immunoassay coupled with inductively coupled plasma-mass spectrometry (ICP-MS) detection has the potential to revolutionize immunoassay analysis in clinical detection; however, a systematic evaluation with the standard guidelines of the assay is needed to ensure its performance meets the requirements of the clinical laboratory.MethodsCarcinoembryonic antigen (CEA) was chosen for analysis using the proposed method. A systematic evaluation of the proposed assay was carried out according to the Clinical and Laboratory Standards Institute (CLSI). The 469 clinical samples were analyzed using the new method and compared with the electrochemiluminescent immunoassay (ECLIA) method.ResultsThe measurement range of the assay was 1–900 ng/mL, with a detection limit of 0.83 ng/mL. The inter-assay and intra-assay imprecision were 4.67% and 5.38% with high concentration samples, and 9.27% and 17.64% with low concentration samples, respectively. The cross-reactivity (%) for different antigens was less than 0.05%, and the recovery was between 94% and 108%. Percentage deviation of all the dilutions was less than 12.5% during linearity estimation. The interference bias caused by different substances was less than 10%. The reference interval of the assay was 0–4.442 ng/mL. Comparison with the commercial ECLIA method for clinical sample detection, the proposed method showed a correlation of 0.9878 and no significant differences between the methods were observed (p = 0.6666).ConclusionsThe ICP-MS based immunoassay was successfully developed, and the analytical performance of the assay met the requirements of the CLSI, which fully proved the clinical transferability and application of the new method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.