title: Ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon mediated circular strand displacement polymerization and hyperbranched rolling circle amplification.
abstract: Using a cascade signal amplification strategy, an ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon (MB) mediated circular strand displacement polymerization (CSDP) and hyperbranched rolling circle amplification (HRCA) was proposed. The hybridization of MB probe to target DNA resulted in a conformational change of the MB and triggered the CSDP in the presence of bio-primer and Klenow fragment (KF exo(-)), leading to multiple biotin-tagged DNA duplex. Furthermore, the HRCA was implemented to product amounts of double-stranded DNA (ds-DNA) fragments using phi29 DNA polymerase via biotin-streptavidin interaction. After the product of HRCA binded numerous biotinylated detection probes, an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor exhibited excellent detection sensitivity and specificity with a log-linear response to target DNA from 0.01 fM to 10 pM as low as 8.9 aM. The proposed method allowed DNA detection with simplicity, rapidness, low cost and high specificity, which might have the potential for application in clinical molecular diagnostics and environmental monitoring.
authors: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors: Xiaolu
authors: X
authors: Li
authors: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors: Jing
authors: J
authors: Guo
authors: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors: Qian
authors: Q
authors: Zhai
authors: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors: Jing
authors: J
authors: Xia
authors: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address: yigang666@126.com.
authors: Gang
authors: G
authors: Yi
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis*; D055664:Electrochemical Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D021141:Nucleic Acid Amplification Techniques; D009693:Nucleic Acid Hybridization; D058105:Polymerization
chemical_list: D006046:Gold; D004247:DNA
keywords: Circular strand displacement polymerization; Electrochemical DNA sensor; Hyperbranched rolling circle amplification; Signal amplification