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Ratiometric electrochemical immunoassay based on internal reference value for reproducible and sensitive detection of
Xiaohui Cai1, Shaohuang Weng1, Rubin Guo1
1Department of Pharmaceutical Analysis, Faculty of Pharmacy, the Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, Fujian Medical University, Fuzhou 350108, China.
Insights
This study presents a novel ratiometric electrochemical immunosensor for detecting carcinoembryonic antigen (CEA), a tumor marker. The advanced sensor offers a simple, accurate, and sensitive method for cancer diagnosis.
Area of Science:
- Electrochemistry
- Biosensors
- Biomarker Detection
Background:
- Electrochemical immunosensors are crucial for detecting tumor markers.
- Existing methods often face challenges with simplicity and accuracy.
- Carcinoembryonic antigen (CEA) is a significant tumor marker for various cancers.
Purpose of the Study:
- To develop a ratiometric electrochemical immunosensor for enhanced simplicity and accuracy in tumor marker detection.
- To utilize a novel electrode modification strategy for reliable signal referencing.
- To establish a sensitive and specific detection method for carcinoembryonic antigen (CEA).
Main Methods:
- Fabrication of an electrochemical immunosensor using Polythionine-gold (PTh-Au) nanocomposite for electrode modification.
- Incorporation of K3[Fe(CN)6] as an indicator signal and PTh-Au as a stable internal reference signal.
- Development of a ratiometric assay based on the ratio of indicator signal changes to the stable reference signal.
Main Results:
- The immunosensor demonstrated high sensitivity and specificity for CEA detection.
- A wide linear detection range from 0.005 ng/mL to 40 ng/mL was achieved.
- A low detection limit of 2.2 pg/mL for CEA was obtained, indicating superior performance.
- The ratiometric approach ensured reliable and reproducible measurements.
Conclusions:
- The developed ratiometric electrochemical immunosensor provides a simple, accurate, and sensitive platform for CEA detection.
- The PTh-Au modified electrode and K3[Fe(CN)6] system offer a robust internal reference for improved assay performance.
- This method holds potential for broader application in detecting other protein biomarkers for disease diagnosis.
Abstract:
A ratiometric assay in an electrochemical immunosensor for tumor marker, herein carcinoembryonic antigen (CEA) was chosen as a model analyte, was developed to improve simplicity and accuracy. The immunosensor was fabricated via the simple expedient way of using Polythionine-gold (PTh-Au) as electrode modified material to be an internal reference signal and K3[Fe(CN)6] in electrolyte as an indicator signal. When the CEA was fixed on the modified electrode via immunoreaction, only the indicator signal sensitively altered; by contrast, the internal reference signal of PTh-Au remained constant at a suitable pH of the electrolyte. The ratio between the alterations of the indicator signal of K3[Fe(CN)6] and the constant internal reference signal can be used to monitor the concentration of CEA reliably, reproducibly, and sensitively. The prepared ratiometric electrochemical immunosensor could detect CEA with good specificity within a wide linear range from 0.005ng/ml to 40ng/ml with a detection limit of 2.2pg/ml. Additionally, experimental results confirm that our proposed method is practical. Thus, this method can expand to recognize and test other protein markers.
