A New Electrochemical Sensor for DNA Detection Based on Au Nanoparticles Surface-Modified with β-Cyclodextrins

Abstract:

We herein constructed a sensor that converts target DNA hybridization-induced conformational transformation of the probe DNA to electrochemical response based on host-guest recognition and nanoparticle label. In the sensor, the hairpin DNA terminal-labeled with 4-((4-(dimethylamino)phenyl)azo)benzoic acid (dabcyl) and NH2 group was immobilized on multi-walled carbon nanotube modified glassy carbon electrode (MCNTs/GCE) surface, and the Au nanoparticles surface-modified with b-cyclodextrins (CD-AuNPs) were employed as electrochemical signal provider and host-guest recognition element. Initially, the probe DNA immobilized on electrode kept the stem-loop configuration, which shielded dabcyl from docking with the CD-AuNPs in solution due to the steric effect. After target hybridization, the probe DNA underwent a significant conformational change, which forced dabcyl away from the electrode. As a result, formerly-shielded dabcyl became accessible to host-guest recognition between b-cyclodextrin (b-CD) and dabcyl, thus the target hybridization event could be sensitively transduced to electrochemical signal provided by CD-AuNPs. This host-guest recognition-based electrochemical sensor has been able to detect as low as picomolar DNA target with excellent differentiation ability for even single mismatch.

• Periodical: Applied Mechanics and Materials (Volumes 423-426)
• Pages: 2330-2333
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.423-426.2330
• Online since: September 2013
• Authors: Lin Cheng, Cui Han Feng, Hao Fan
• Keywords: Au Nanoparticles, Cyclodextrins, DNA, Electrochemical Sensor, Host-Guest Recognition

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