Design of an oligonucleotide-incorporated nonfouling surface and its application in electrochemical DNA sensors for highly sensitive and sequence-specific detection of target DNA.
In this work, we report a novel electrochemical DNA sensor based on a nonfouling monolayer structure self-assembled at gold surfaces. Self-assembled monolayers (SAMs) with oligo(ethylene glycol) (OEG)-terminated thiols are known to be highly protein-resistant and effectively repel nonspecific adsorption. We found that a mixed SAM structure incorporating thiolated oligonucleotides and OEG thiols (SH-DNA/OEG) exhibited the similar non-fouling feature. More importantly, it allowed facile electron transfer across the monolayer and thus was fully compatible with electrochemical detection. On the basis of this SH-DNA/OEG platform, we developed a sandwich-type electrochemical sensor for the sequence-specific detection of DNA targets. This sensor was able to detect as little as 1 pM target DNA even in the presence of complicated biological fluids such as human serum. We also employed this sensor to directly detect a polymerase chain reaction (PCR) amplicon from the genomic DNA of Escherichia coli K12, which led to a very low detect limit of 60 fg (approximately 10 copies).
Zhang
Jiong
J
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Lao
Ruojun
R
Song
Shiping
S
Yan
Zhuoyan
Z
Fan
Chunhai
C
D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000097:blood; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D004563:Electrochemistry / Q000379:methods*; D004926:Escherichia coli / Q000737:chemistry; D019855:Ethylene Glycol / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D009841:Oligonucleotides / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
D004269:DNA, Bacterial; D009841:Oligonucleotides; D013438:Sulfhydryl Compounds; D006046:Gold; D004247:DNA; D019855:Ethylene Glycol