earticle

영어

Lipopolysaccharide (LPS), also known as endotoxin, is a major component of the outer membrane of Gram-negative bacteria and triggers a fatal septic shock upon its internalization into mammalian cells.1 Fast and accurate detection of even small amount of LPS in therapeutic products and the blood purification is therefore of primary importance. Several LPS affinity binders have been reported by far but few of them have proved their efficacy in developing electrochemical sensors capable of selectively detecting LPS from crude biological liquors.2-4 In this study, we identified 10 different single stranded DNA aptamers (designated as B1 to B10) showing specific affinity to LPS with dissociation constants (Kd) in the nanomolar range using 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 as a sensing probe 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 1 ng/mL of LPS with significantly reduced detection time compared with the traditional Limulus Amoebocyte Lysate (LAL) assay.