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Updated: Oct 21, 2025
Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Fabrication of electrochemical biosensor composed of multi-functional DNA 4 way junction for TNF-α detection in human
Jinmyeong Kim1, Seung Woo Noh1, Chulhwan Park1
1Department of Chemical Engineering, Kwangwoon University, 20 Kwangwoon-Ro,Nowon-Gu, Seoul 01897, Republic of Korea.
Abstract:
Tumor necrosis factor (TNF-α) is a representative cytokine family known to induce multiple signaling cascades leading to various cellular responses, such as cell death, survival, and differentiation. It has been reported that blocking the action of TNF-α in various diseases can improve disease prognosis. Therefore, it is important to monitor TNF-α in patient plasma and properly regulate its action. In this study, we report a label-free electrochemical biosensor consisting of a multifunctional DNA 4-way junction (MF-4WJ) for TNF-α detection in human serum. MF-4WJ does not require additional labeling and signal amplification processes. The electrochemical properties of functionalized MF-4WJ were evaluated by cyclic voltammetry (CV) in the presence of Ag+ intercalated between the mismatched sequences of MF-aptamers as redox-active species. Afterward, CV was carried out to evaluate the performance of the fabricated biosensor. The proposed label-free electrochemical biosensor was able to effectively detect TNF-α in a dynamic range of 0.15 pg/ml to 150 ng/ml. Limit of detection (LOD) was at 0.07 pg/ml in HEPES. Moreover, it was confirmed that even in 10% diluted human serum, TNF-α could be detected in an excellent dynamic range of 0.15 pg/ml to ∼ 15 ng/ml and LOD was at 0.14 pg/ml in 10% diluted human serum.
Insights
This study introduces a novel label-free electrochemical biosensor using a DNA 4-way junction for sensitive detection of Tumor Necrosis Factor-alpha (TNF-α) in human serum, crucial for disease monitoring.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Molecular Biology
Background:
- Tumor necrosis factor-alpha (TNF-α) is a key cytokine regulating cellular responses and implicated in various diseases.
- Monitoring TNF-α levels is critical for disease prognosis and therapeutic intervention.
- Existing detection methods may require complex labeling or amplification steps.
Purpose of the Study:
- To develop a label-free electrochemical biosensor for sensitive and accurate detection of TNF-α.
- To utilize a multifunctional DNA 4-way junction (MF-4WJ) as the core sensing element.
- To validate the biosensor's performance in human serum samples.
Main Methods:
- Fabrication of an electrochemical biosensor using a multifunctional DNA 4-way junction (MF-4WJ).
- Evaluation of electrochemical properties using cyclic voltammetry (CV) with silver ions (Ag+) as redox indicators.
- Testing the biosensor's detection capabilities in buffer and diluted human serum.
Main Results:
- The label-free biosensor demonstrated effective TNF-α detection in a wide dynamic range (0.15 pg/ml to 150 ng/ml).
- Achieved a low limit of detection (LOD) of 0.07 pg/ml in HEPES buffer.
- Successfully detected TNF-α in 10% diluted human serum with a dynamic range of 0.15 pg/ml to ~15 ng/ml and LOD of 0.14 pg/ml.
Conclusions:
- The MF-4WJ based electrochemical biosensor offers a sensitive and label-free platform for TNF-α detection.
- This biosensor shows significant potential for clinical diagnostics and disease monitoring in biological samples.
- The label-free nature simplifies the detection process, reducing complexity and cost.
