An enzyme-based E-DNA sensor for sequence-specific detection of femtomolar DNA targets.
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.
Liu
Gang
G
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Wan
Ying
Y
Gau
Vincent
V
Zhang
Jiong
J
Wang
Lihua
L
Song
Shiping
S
Fan
Chunhai
C
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
D004269:DNA, Bacterial; D004800:Enzymes, Immobilized; D009841:Oligonucleotides; D001360:Avidin; D001710:Biotin; D019809:Streptavidin; D006735:Horseradish Peroxidase; D004076:Digoxigenin