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Homogeneous fluorescence-based immunoassay via inner filter effect of gold nanoparticles on fluorescence of CdTe
Xiang Cui1, Mei Liu, Baoxin Li
1Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
Insights
A new homogeneous immunoassay platform utilizes gold nanoparticles and CdTe QDs for sensitive human immunoglobulin (IgG) detection. This rapid, cost-effective method offers improved performance for medical diagnostics.
Area of Science:
- Nanotechnology-based biosensing
- Fluorescence spectroscopy
- Immunoassay development
Background:
- Homogeneous immunoassays offer advantages over heterogeneous methods in diagnostics.
- Gold nanoparticles (AuNPs) and quantum dots (QDs) are promising nanomaterials for biosensing.
- Sensitive detection of human immunoglobulin G (IgG) is crucial for disease diagnosis.
Purpose of the Study:
- To develop a universal platform for homogeneous immunoassay using human IgG as a model analyte.
- To leverage the inner filter effect (IFE) of AuNPs on CdTe QDs fluorescence for enhanced sensitivity.
- To establish a simple, rapid, and sensitive method for IgG quantification.
Main Methods:
- Utilized antibody-functionalized AuNPs and CdTe QDs.
- Exploited the inner filter effect (IFE) between AuNPs and CdTe QDs.
- Induced AuNP aggregation upon antigen-antibody immunoreaction to modulate fluorescence.
- Quantified IgG based on fluorescence intensity changes.
Main Results:
- Achieved a wide dynamic range of 1-100 pg/mL for IgG determination.
- Obtained a low detection limit of 0.3 pg/mL for human IgG.
- Demonstrated successful application in human serum samples, with results comparable to ELISA.
Conclusions:
- The developed homogeneous immunoassay platform is simple, rapid, cheap, and highly sensitive.
- The IFE-based fluorescence quenching assay provides a sensitive method for IgG detection.
- This approach holds potential for advanced medical diagnostic applications.
Abstract:
Homogeneous immunoassays are becoming more and more attractive for modern medical diagnosis because they are superior to heterogeneous immunoassays in sample and reagent consumption, analysis time, portability and disposability. Herein, a universal platform for homogeneous immunoassay, using human immunoglobulin (IgG) as a model analyte, has been developed. This assay relies upon the inner filter effect (IFE) of gold nanoparticles (AuNPs) on CdTe QDs fluorescence. The immunoreaction of antigen and antibody can induce the aggregation of antibody-functionalized AuNPs, and after aggregation the IFE of AuNPs on CdTe QDs fluorescence is greatly enhanced, resulting in a decrease of fluorescence intensity in the system. Based on this phenomenon, a wide dynamic range of 1-100 pg mL(-1) for determination of IgG can be obtained. The proposed method shows a detection limit of 0.3 pg mL(-1) for human IgG, which is much lower than the corresponding absorbance-based approach and compares favorably with other reported fluorescent methods. This immunoassay method is simple, rapid, cheap, and sensitive. The proposed method has been successfully applied to measuring IgG in serum samples, and the obtained results agreed well with those of the enzyme-linked immunosorbent assay (ELISA).
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