Harnessing aptamers for electrochemical detection of endotoxin

Lipopolysaccharide (LPS), also known as endotoxin, triggers a fatal septic shock; therefore, fast and accurate detection of LPS from a complex milieu is of primary importance. Several LPS affinity binders have been reported so far but few of them have proved their efficacy in developing electrochemi...

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Bibliographic Details
Published in:Analytical biochemistry 2012-05, Vol.424 (1), p.12-20
Main Authors: Kim, Sung-Eun, Su, Wenqiong, Cho, MiSuk, Lee, Youngkwan, Choe, Woo-Seok
Format: Article
Language:English
Subjects:
Aptamer
Aptamers, Nucleotide - chemistry
Aptamers, Nucleotide - genetics
Base Sequence
Biosensing Techniques
biosensors
dissociation
Electric Impedance
Electrochemical aptasensor
Electrochemical Techniques - methods
electrochemistry
Electrodes
Electrons
Electrophoresis, Capillary
endotoxins
Gene Library
gold
Gold - chemistry
impedance
Kinetics
Limulus
Lipopolysaccharide
lipopolysaccharides
Lipopolysaccharides - analysis
Molecular Sequence Data
NECEEM-based non-SELEX
Nucleic Acid Conformation
oligonucleotides
septic shock
single-stranded DNA
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Summary:Lipopolysaccharide (LPS), also known as endotoxin, triggers a fatal septic shock; therefore, fast and accurate detection of LPS from a complex milieu is of primary importance. Several LPS affinity binders have been reported so far but few of them have proved their efficacy in developing electrochemical sensors capable of selectively detecting LPS from crude biological liquors. In this study, we identified 10 different single-stranded DNA aptamers showing specific affinity to LPS with dissociation constants (Kd) in the nanomolar range using a NECEEM-based non-SELEX method. Based on the sequence and secondary structure analysis of the LPS binding aptamers, an aptamer exhibiting the highest affinity to LPS (i.e., B2) was selected to construct an impedance biosensor on a gold surface. The developed electrochemical aptasensor showed excellent sensitivity and specificity in the linear detection range from 0.01 to 1ng/mL of LPS with significantly reduced detection time compared with the traditional Limulus amoebocyte lysate (LAL) assay.
ISSN:0003-2697
1096-0309
DOI:10.1016/j.ab.2012.02.016