title: Ultrasensitive electrochemical detection of nucleic acid by coupling an autonomous cascade target replication and enzyme/gold nanoparticle-based post-amplification.
abstract: Owing to the intrinsic importance of nucleic acid as bio-targets, the development of isothermal and ultrasensitive electrochemical DNA biosensor is very essential for biological studies and medical diagnostics. Herein, the autonomous cascade DNA replication strategy was effectively married with the enzyme/gold nanoparticle-based post-amplification strategy to promote the detection performance toward target DNA. A hairpin DNA probe (HP) is designed that consists of an overhang at 3'-end as the recognition unit for target DNA, a recognition site for nicking endonuclease, and an alkane spacer to terminate polymerization reaction. The autonomous DNA replication-scission-displacement reaction operated by the nicking endonuclease/KF polymerase induced the autocatalytic opening of HP, which was then specifically bound by the enzyme/gold nanoparticles for further dual-signal amplification toward target-related sensing events. A low detection limit of 0.065 fM with an excellent selectivity toward target DNA could be achieved. The proposed biosensor could be also easily regenerated for target detection. The developed biosensor creates an opportunity for the effective coupling of the target replication with post-amplification strategies and thus opens a promising avenue for the detection of nucleic acid with low abundance in bioanalysis and clinical biomedicine.
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China. Electronic address: sliu@qust.edu.cn.
authors: Shufeng
authors: S
authors: Liu
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
authors: Wenji
authors: W
authors: Wei
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
authors: Yanqun
authors: Y
authors: Wang
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
authors: Li
authors: L
authors: Fang
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China. Electronic address: wangli@qust.edu.cn.
authors: Li
authors: L
authors: Wang
authors: College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China. Electronic address: lifeng@qust.edu.cn.
authors: Feng
authors: F
authors: Li
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification*; D015342:DNA Probes / Q000737:chemistry; D004261:DNA Replication; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D006046:Gold; D004247:DNA
keywords: DNA biosensor; Electrochemistry; Gold nanoparticle; Target replication; signal amplification