title: An enzyme-based E-DNA sensor for sequence-specific detection of femtomolar DNA targets.
abstract: In this work, we report an enzyme-based E-DNA sensor for the sequence-specific detection of nucleic acids. This DNA sensor employs a "stem-loop" DNA probe dually labeled with biotin and digoxigenin (DIG). The probe is immobilized at an avidin-modified electrode surface via the biotin-avidin bridge, and the DIG serves as an affinity tag for the enzyme binding. In the initial state of the sensor, the probe adopts the stem-loop structure, which shields DIG from being approached by a bulky horseradish peroxidase-linked-anti-DIG antibody (anti-DIG-HRP) due to the steric effect. After hybridization, the probe undergoes a significant conformational change, forcing DIG away from the electrode. As a result, the DIG label becomes accessible by the anti-DIG-HRP, and the target hybridization event can be sensitively transduced via the enzymatically amplified electrochemical current signal. By using this new strategy, we demonstrate that the prototype E-DNA sensor has been able to detect as low as femtomolar DNA targets with excellent differentiation ability for even single mismatches.
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wan
authors.forename: Vincent
authors.initials: V
authors.lastname: Gau
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhang
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.forename: Shiping
authors.initials: S
authors.lastname: Song
authors.forename: Chunhai
authors.initials: C
authors.lastname: Fan
mesh_terms: D001360:Avidin / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D004076:Digoxigenin / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics; D006735:Horseradish Peroxidase / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry* / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D019809:Streptavidin / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D004800:Enzymes, Immobilized; D009841:Oligonucleotides; D001360:Avidin; D001710:Biotin; D019809:Streptavidin; D006735:Horseradish Peroxidase; D004076:Digoxigenin