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Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
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Building a Nucleic Acid Nanostructure with DNA-Epitope Conjugates for a Versatile Approach to Electrochemical Protein
Asanka Gurukandure1, Subramaniam Somasundaram1, Amanda S N Kurian1
1Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States.
Analytical Chemistry
|November 30, 2023
Summary
Researchers developed a novel nucleic-acid-based electrochemical sensor for detecting larger proteins, including biomarkers like creatine kinase. This adaptable platform offers rapid, sensitive, and generalizable detection in human serum, advancing clinical diagnostics.
Area of Science:
- Electrochemistry
- Nucleic Acid Nanotechnology
- Biosensing
Background:
- Nucleic acid-based electrochemical (EC) sensors offer generalizable analyte detection.
- Existing EC platforms face challenges in quantifying larger proteins.
- A nucleic acid nanostructure utilizing enzymatic ligation was previously developed for EC readout.
Purpose of the Study:
- To adapt and validate a generalized EC sensor platform for the quantification of larger proteins.
- To demonstrate the sensor's capability in detecting specific protein biomarkers in complex biological matrices.
- To expand the applicability of EC sensing to clinically relevant proteins previously inaccessible to these techniques.
Main Methods:
- Conjugation of minimized antibody-binding epitopes to a central DNA strand within a nanostructure.
- Development of a competitive immunoassay using DNA-epitope conjugates and square-wave voltammetry (SWV).
- Validation of the sensor using creatine kinase (CK-MM) as a model protein biomarker in human serum.
Main Results:
- The adapted sensor enabled signal-off detection of anti-CK antibody with a limit of detection (LOD) of 5 nM and a 3-min response time.
- Signal-on detection of CK protein showed a sensing range from 14 nM to 100 nM, overlapping the clinical range.
- The sensor demonstrated high performance, with 98% validation in human serum, despite a need for improved conjugate purification.
Conclusions:
- The DNA-epitope conjugation strategy successfully adapted the EC sensor for generic protein quantification.
- This approach facilitates the quantitative detection of protein- or peptide-binding antibodies.
- The developed platform holds significant potential for future quantitative EC readouts of various clinically relevant proteins.
