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Homogeneous Electrochemical Immunoassay Using an Aggregation-Collision Strategy for Alpha-Fetoprotein Detection
Jian-Hua Zhang1,2, Meijuan Liu1, Feng Zhou3
1Institute of Chemical Biology and Nanomedicine (ICBN), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Insights
This study introduces a novel homogeneous electrochemical immunoassay for detecting alpha-fetoprotein (AFP), a tumor biomarker. The assay utilizes an aggregation-collision strategy with nanoimpact electrochemistry for sensitive and specific AFP quantification in patient samples.
Area of Science:
- Biomarker Detection
- Nanomaterials in Diagnostics
- Electrochemical Immunoassays
Background:
- Homogeneous immunoassays offer advantages over heterogeneous assays but face challenges in electrochemical applications due to immobilization requirements.
- Developing efficient homogeneous electrochemical assays is crucial for advanced diagnostics.
Purpose of the Study:
- To develop a novel homogeneous electrochemical immunoassay for quantifying alpha-fetoprotein (AFP).
- To utilize an aggregation-collision strategy with nanoimpact electrochemistry for enhanced sensitivity and specificity.
Main Methods:
- Employing silver nanoparticles (AgNPs) functionalized with anti-AFP antibodies for AFP recognition.
- Inducing AgNP aggregation upon AFP binding, altering nanoparticle size and concentration.
- Utilizing nanoimpact electrochemistry (NIE) for sensitive detection of aggregated AgNPs via oxidation.
Main Results:
- Achieved a highly sensitive limit of detection (LOD) of 5 pg/mL for AFP.
- Demonstrated high specificity and efficiency in AFP quantification.
- Successfully detected AFP in diluted human serum samples from hepatocellular carcinoma (HCC) patients.
Conclusions:
- The developed NIE-based homogeneous immunoassay provides a sensitive and specific method for AFP detection.
- This approach overcomes limitations of traditional electrochemical immunoassays.
- Shows significant potential for application in HCC liquid biopsy for early diagnosis and monitoring.
Abstract:
Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity and high efficiency. Homogeneous electrochemical assays, however, are not commonly accessed due to the requirement of electrode immobilization of the recognition elements. Herein, we demonstrate a new homogeneous electrochemical immunoassay based on the aggregation-collision strategy for the quantification of tumor protein biomarker alpha-fetoprotein (AFP). The detection principle relies on the aggregation of AgNPs induced by the molecular biorecognition between AFP and AgNPs-anti-AFP probes, which leads to an increased AgNP size and decreased AgNP concentration, allowing an accurate self-validated dual-mode immunoassay by performing nanoimpact electrochemistry (NIE) of the oxidation of AgNPs. The intrinsic one-by-one analytical capability of NIE as well as the participation of all of the atoms of the AgNPs in signal transduction greatly elevates the detection sensitivity. Accordingly, the current sensor enables a limit of detection (LOD) of 5 pg/mL for AFP analysis with high specificity and efficiency. More importantly, reliable detection of AFP in diluted human sera of hepatocellular carcinoma (HCC) patients is successfully achieved, indicating that the NIE-based homogeneous immunoassay shows great potential in HCC liquid biopsy.
