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Triplex DNA-Modified Gold Nanoparticles with a Tunable pH Detection Range for Multiple Colorimetric Sensing
Le Liu1, Siting Fu1, Wenting Chang1
1School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, P. R. China.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 5, 2025
Summary
We developed pH-responsive DNA-modified gold nanoparticles that change color. This innovation allows for tunable detection of acidity in applications like acid-base titrations and environmental monitoring.
Area of Science:
- Nanotechnology
- Biochemistry
- Materials Science
Background:
- Gold nanoparticles (AuNPs) are widely used in diagnostics and sensing.
- DNA nanotechnology offers precise control over material properties.
- pH-responsive materials are crucial for various analytical applications.
Purpose of the Study:
- To design and synthesize pH-responsive gold nanoparticles.
- To create a colorimetric sensor for detecting pH changes.
- To demonstrate the tunable nature of the sensor's pH response.
Main Methods:
- Modification of gold nanoparticles with homopyrimidine DNA strands.
- Formation of triplex DNA structures via Watson-Crick and Hoogsteen base pairing upon acidification.
- Utilizing DNA outer layer base stacking for nanoparticle aggregation and color change.
Main Results:
- Successfully designed pH-responsive triplex DNA-modified gold nanoparticles.
- Demonstrated tunable pH response by altering the A/T proportion in DNA strands.
- Achieved colorimetric detection through nanoparticle aggregation.
Conclusions:
- The developed gold nanoparticles provide a novel platform for pH sensing.
- The system shows potential for accurate acid-base titration and visual determination of acid rain.
- Colorimetric detection of 3-nitropropionic acid in sugarcane is feasible.
