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Author Spotlight: Advancements in DNA Nanosensors – Addressing Sensitivity and Selectivity Challenges in Molecular Detection
Published on: February 9, 2024
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In vitro selection of a sodium-specific DNAzyme and its application in intracellular sensing
Seyed-Fakhreddin Torabi1, Peiwen Wu1, Claire E McGhee2
1Departments of Biochemistry.
Summary
Researchers developed a novel fluorescent sensor using a sodium (Na(+))-specific DNAzyme. This sensor detects Na(+) in living cells with high selectivity and can be activated on demand.
Area of Science:
- Biochemistry
- Molecular Biology
- Chemical Biology
Background:
- Fluorescent sensors for divalent metal ions are well-developed.
- Monovalent ion sensors, particularly for sodium (Na(+)), are underdeveloped despite Na(+)s biological importance.
Purpose of the Study:
- To develop the first Na(+)-specific, RNA-cleaving deoxyribozyme (DNAzyme).
- To transform the DNAzyme into a fluorescent sensor for Na(+) detection.
- To enable intracellular Na(+) detection in living cells.
Main Methods:
- In vitro selection of a Na(+)-specific DNAzyme.
- Labeling DNAzyme and substrate strands with fluorophores and quenchers.
- Utilizing α-helical cationic polypeptides for cellular delivery.
- Employing a photolabile group for controlled sensor activation.
Main Results:
- Developed a Na(+)-specific DNAzyme with a fast catalytic rate (ko(bs) ~ 0.1 min(-1)).
- Created a fluorescent sensor with >10,000-fold selectivity for Na(+) over other ions.
- Achieved a detection limit of 135 µM (3.1 ppm) for Na(+).
- Demonstrated cellular uptake and controlled activation of the sensor in living cells.
Conclusions:
- The Na(+)-specific DNAzyme is a promising platform for fluorescent sensing.
- The developed sensor enables sensitive and selective detection of Na(+) in living cells.
- Controlled activation allows for spatiotemporal monitoring of intracellular Na(+).
