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Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions
Published on: July 22, 2013
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Functional Single-Walled Carbon Nanotubes for Anion Sensing.
Seon-Jin Choi1,2, Bora Yoon3,4, Sibo Lin1,3
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
ACS Applied Materials & Interfaces
|June 11, 2020
Summary
This study introduces a new platform for detecting anions using electrical signals. The system selectively senses acetate ions through chemical interactions, offering high sensitivity and potential for advanced chemical sensing applications.
Area of Science:
- Chemical Sensing
- Materials Science
- Electrochemistry
Background:
- Development of selective anion sensors is crucial for environmental monitoring and diagnostics.
- Existing methods often lack sensitivity or selectivity for specific anions.
- Conductance-based sensing platforms offer potential for real-time detection.
Purpose of the Study:
- To develop a highly sensitive and selective anion-sensing platform.
- To investigate the mechanism of anion binding and signal transduction.
- To integrate a novel selector molecule with a conductive nanomaterial.
Main Methods:
- Synthesis of a selector molecule with cationic and hydrogen-bonding moieties.
- Spectroscopic studies (1H NMR, UV-vis) to characterize anion binding.
- Density Functional Theory (DFT) calculations to understand binding interactions.
- Covalent attachment of the selector to poly(4-vinylpyridine) wrapped single-walled carbon nanotubes (P4VP-2-SWCNT).
- Electrical conductance measurements for anion sensing.
Main Results:
- The selector demonstrated preferential binding to acetate ions (AcO-) over chloride (Cl-), bromide (Br-), and nitrate (NO3-).
- Selector 2 undergoes deprotonation with AcO- and hydrogen bonding with other anions.
- The P4VP-2-SWCNT platform exhibited high sensitivity to AcO- (101.9 ± 10.3% resistance change at 16.7 mM).
- Negligible response was observed for Cl-, Br-, and NO3-, indicating high selectivity.
- DFT calculations and spectroscopic titrations confirmed the role of the pyridinium moiety in enhancing binding affinity.
Conclusions:
- The developed platform enables continuous and selective anion sensing based on conductance changes.
- The selector's design, featuring a cationic pyridinium and a thiourea group, is key to its sensing capabilities.
- Deprotonation of the selector upon acetate binding drives the observed electrical signal transduction.
- This work presents a promising approach for developing advanced electrochemical sensors for specific anion detection.
