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Rapid and quantitative detection of C-reactive protein using quantum dots and immunochromatographic test strips.

Cheng X, Pu X, Jun P, Zhu X, Zhu D, Chen M - Int J Nanomedicine (2014)

Bottom Line: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5-300 mg/L).The intra-assay and interassay coefficients of variation were 8.95% and 9.86% at 0.5 mg/L, 6.47% and 8.66% at 10 mg/L, and 6.81% and 9.10% at 60 mg/L, respectively.In a comparison between clinical samples, the results of this QD-based assay of CRP levels were significantly correlated with those of an Immulite 2000 assay (R=0.993, P<0.001).

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei, People's Republic of China.

ABSTRACT

Background: Rapid immunochromatographic tests can detect disease markers in 10-15 minutes, which facilitates clinical diagnosis and treatment programs. However, most immunochromatographic tests employ gold nanoparticles as reporters, and these have only moderate sensitivity and act as qualitative methods for analyzing high biomarker concentrations.

Methods: In this study, we introduce quantum dots (QDs) as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT) to analyze C-reactive protein (CRP) levels. Goat anti-rabbit IgG and rabbit IgG were used as control antibodies, and mouse monoclonal CRP antibody pairs were used for disease marker detection. One monoclonal CRP antibody was conjugated with QDs and served as a signal antibody, and the other monoclonal CRP antibody was dispensed onto the nitrocellulose membrane and served as a capturing antibody. In the presence of CRP, the fluorescence intensity of the monoclonal antibody-CRP-monoclonal antibody sandwich complex captured on the nitrocellulose membrane was determined using the fluorescence strip reader.

Results: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5-300 mg/L). The intra-assay and interassay coefficients of variation were 8.95% and 9.86% at 0.5 mg/L, 6.47% and 8.66% at 10 mg/L, and 6.81% and 9.10% at 60 mg/L, respectively. In a comparison between clinical samples, the results of this QD-based assay of CRP levels were significantly correlated with those of an Immulite 2000 assay (R=0.993, P<0.001).

Conclusion: Our results demonstrated that the QD-based immunochromatographic test is a rapid, sensitive, accurate, and quantitative method for the detection of disease biomarkers.

Show MeSH
Fluorescence intensity readout curve of QD-POCT strips using portable fluorescence strip readers for concentrations of 0.5 mg/L, 3 mg/L, 20 mg/L, 100 mg/L, and 200 mg/L C-reactive protein.Abbreviations: QD, quantum dot; POCT, fluorescence point-of-care test.
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f3-ijn-9-5619: Fluorescence intensity readout curve of QD-POCT strips using portable fluorescence strip readers for concentrations of 0.5 mg/L, 3 mg/L, 20 mg/L, 100 mg/L, and 200 mg/L C-reactive protein.Abbreviations: QD, quantum dot; POCT, fluorescence point-of-care test.

Mentions: Five different concentrations (0.5, 3, 20, 100, and 200 mg/L) of the human CRP standard samples were measured using the QF-POCT assay system. The fluorescent band could clearly be observed by ultraviolet excitation. The changes in fluorescent intensity of the test lines were associated with the concentration of CRP; in contrast, the fluorescence intensity of the control lines remained the same regardless of CRP concentration (Figure 2A–E). The fluorescence intensity readout curves of the portable fluorescence strip reader are shown in Figure 3. Supplementary Figure 1A–E shows the raw fluorescence intensity readout curves of the QD-POCT strips using portable fluorescence strip readers.


Rapid and quantitative detection of C-reactive protein using quantum dots and immunochromatographic test strips.

Cheng X, Pu X, Jun P, Zhu X, Zhu D, Chen M - Int J Nanomedicine (2014)

Fluorescence intensity readout curve of QD-POCT strips using portable fluorescence strip readers for concentrations of 0.5 mg/L, 3 mg/L, 20 mg/L, 100 mg/L, and 200 mg/L C-reactive protein.Abbreviations: QD, quantum dot; POCT, fluorescence point-of-care test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260658&req=5

f3-ijn-9-5619: Fluorescence intensity readout curve of QD-POCT strips using portable fluorescence strip readers for concentrations of 0.5 mg/L, 3 mg/L, 20 mg/L, 100 mg/L, and 200 mg/L C-reactive protein.Abbreviations: QD, quantum dot; POCT, fluorescence point-of-care test.
Mentions: Five different concentrations (0.5, 3, 20, 100, and 200 mg/L) of the human CRP standard samples were measured using the QF-POCT assay system. The fluorescent band could clearly be observed by ultraviolet excitation. The changes in fluorescent intensity of the test lines were associated with the concentration of CRP; in contrast, the fluorescence intensity of the control lines remained the same regardless of CRP concentration (Figure 2A–E). The fluorescence intensity readout curves of the portable fluorescence strip reader are shown in Figure 3. Supplementary Figure 1A–E shows the raw fluorescence intensity readout curves of the QD-POCT strips using portable fluorescence strip readers.

Bottom Line: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5-300 mg/L).The intra-assay and interassay coefficients of variation were 8.95% and 9.86% at 0.5 mg/L, 6.47% and 8.66% at 10 mg/L, and 6.81% and 9.10% at 60 mg/L, respectively.In a comparison between clinical samples, the results of this QD-based assay of CRP levels were significantly correlated with those of an Immulite 2000 assay (R=0.993, P<0.001).

View Article: PubMed Central - PubMed

Affiliation: Department of Laboratory Medicine, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei, People's Republic of China.

ABSTRACT

Background: Rapid immunochromatographic tests can detect disease markers in 10-15 minutes, which facilitates clinical diagnosis and treatment programs. However, most immunochromatographic tests employ gold nanoparticles as reporters, and these have only moderate sensitivity and act as qualitative methods for analyzing high biomarker concentrations.

Methods: In this study, we introduce quantum dots (QDs) as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT) to analyze C-reactive protein (CRP) levels. Goat anti-rabbit IgG and rabbit IgG were used as control antibodies, and mouse monoclonal CRP antibody pairs were used for disease marker detection. One monoclonal CRP antibody was conjugated with QDs and served as a signal antibody, and the other monoclonal CRP antibody was dispensed onto the nitrocellulose membrane and served as a capturing antibody. In the presence of CRP, the fluorescence intensity of the monoclonal antibody-CRP-monoclonal antibody sandwich complex captured on the nitrocellulose membrane was determined using the fluorescence strip reader.

Results: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5-300 mg/L). The intra-assay and interassay coefficients of variation were 8.95% and 9.86% at 0.5 mg/L, 6.47% and 8.66% at 10 mg/L, and 6.81% and 9.10% at 60 mg/L, respectively. In a comparison between clinical samples, the results of this QD-based assay of CRP levels were significantly correlated with those of an Immulite 2000 assay (R=0.993, P<0.001).

Conclusion: Our results demonstrated that the QD-based immunochromatographic test is a rapid, sensitive, accurate, and quantitative method for the detection of disease biomarkers.

Show MeSH