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14:53
A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis
Published on: September 10, 2014
Electrostatically directed visual fluorescence response of DNA-functionalized monolithic hydrogels for highly
Kevin A Joseph1, Neeshma Dave, Juewen Liu
1Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
ACS Applied Materials & Interfaces
|February 18, 2011
Summary
This study demonstrates how positively charged hydrogels significantly reduce background fluorescence in optical sensors. This improves mercury detection by enhancing signal-to-background ratio and lowering detection limits.
Area of Science:
- Polymer Science
- Biomolecular Engineering
- Analytical Chemistry
Background:
- Hydrogels offer tunable properties for biomolecule immobilization in optical sensors.
- Controlling hydrogel properties via monomer composition is key for sensor design.
- Electrostatic interactions in hydrogel-based optical sensors remain underexplored.
Purpose of the Study:
- To investigate electrostatic interactions between DNA, dye, and hydrogel backbone for mercury detection.
- To rationally design hydrogel-based optical sensors by controlling hydrogel charge.
- To optimize mercury detection sensitivity and reduce background noise.
Main Methods:
- Covalently functionalizing thymine-rich DNA within positively, negatively, and neutrally charged hydrogels.
- Utilizing mercury-binding DNA to induce hairpin formation upon Hg(2+) binding.
- Employing SYBR Green I dye for fluorescence detection of hairpin structures.
Main Results:
- Neutral and negatively charged gels exhibited high background fluorescence due to dye binding to unfolded DNA.
- Introducing a positively charged backbone (20% allylamine) significantly reduced background fluorescence.
- Positively charged gels improved signal-to-background ratio by 6-fold and detection limit by 9-fold for mercury detection.
Conclusions:
- Hydrogel backbone charge actively influences molecular interactions, impacting sensor performance.
- Cationic hydrogels effectively minimize non-specific dye binding, enhancing optical sensor sensitivity.
- This work provides insights into electrostatic interactions for designing advanced hydrogel-based biosensors.
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