An electrochemical DNA sensor for sequence-specific DNA recognization in a homogeneous solution.
In this work, a sensitive electrochemical DNA sensor based on an avidin modified electrode and a DNA-functionalized Au nanoparticle (DFNP) was developed. The DNA-functionalized Au nanoparticle contained two kinds of DNA, one is hairpin probe DNA with a biotin at the 3' terminal and a thiol at the 5' terminal, the other is methylene blue (MB)-labeled linear signal DNA. Without hybridizing with the target DNA, the loop of the hairpin impeded biotin linked with avidin on electrode. However, after target hybridization, the hairpin was opened and biotin was recognized by avidin which resulted in a DNA-functionalized Au nanoparticle brought on the electrode surface. Electrochemical signals of MB bound to signal DNA were measured by differential pulse voltammetry (DPV). Taking advantage of amplification effects of the AuNP and binding specificity of the hairpin probe, this DNA biosensor greatly simplified the electrochemical DNA detection method and displayed high specificity in DNA detection. By using this new method, we demonstrate that this prototype sensor has been able to detect as low as picomolar DNA targets with excellent differentiation ability even for a single mismatch.
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China.
Han-Feng
HF
Cui
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China.
Lin
L
Cheng
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China.
Jie
J
Zhang
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China.
Ronghua
R
Liu
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China.
Cheng
C
Zhang
Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China. Electronic address: fanhao11@aliyun.com.
Hao
H
Fan
D001360:Avidin / Q000737:chemistry*; D020137:Base Pair Mismatch; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation; D001710:Biotin / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D015342:DNA Probes / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D012996:Solutions
D015342:DNA Probes; D012996:Solutions; D001360:Avidin; D001710:Biotin; D006046:Gold; D004247:DNA
DNA-functionalized gold nanoparticle; E-DNA sensor; Electrochemical; Homogeneous solution