Enzymatic amplification detection of DNA based on "molecular beacon" biosensors.
We described a novel electrochemical DNA biosensor based on molecular beacon (MB) probe and enzymatic amplification protocol. The MB modified with a thiol at its 5' end and a biotin at its 3' end was immobilized on the gold electrode through mixed self-assembly process. Hybridization events between MB and target DNA cause the conformational change of the MB, triggering the attached biotin group on the electrode surface. Following the specific interaction between the conformation-triggered biotin and streptavidin-horseradish peroxidase (HRP), subsequent quantification of DNA was realized by electrochemical detection of enzymatic product in the presence of substrate. The detection limit is obtained as low as 0.1nM. The presented DNA biosensor has good selectivity, being able to differentiate between a complementary target DNA sequence and one containing G-G single-base mismatches.
Mao
Xun
X
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Jiang
Jianhui
J
Xu
Xiangmin
X
Chu
Xia
X
Luo
Yan
Y
Shen
Guoli
G
Yu
Ruqin
R
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006735:Horseradish Peroxidase / Q000737:chemistry*; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004247:DNA; D006735:Horseradish Peroxidase