School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Anal Biochem. 2012 May 1;424(1):12-20. doi: 10.1016/j.ab.2012.02.016. Epub 2012 Feb 25.
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 (K(d)) 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 1 ng/mL of LPS with significantly reduced detection time compared with the traditional Limulus amoebocyte lysate (LAL) assay.
脂多糖（LPS），也被称为内毒素，会引发致命的感染性休克；因此，从复杂环境中快速准确地检测 LPS 至关重要。目前已经报道了几种 LPS 亲和配体，但其中很少有能够证明其在开发电化学传感器方面的有效性，这些传感器能够选择性地从粗生物液中检测 LPS。在这项研究中，我们使用基于 NECEEM 的非 SELEX 方法，鉴定了 10 种不同的单链 DNA 适体，它们对 LPS 具有特异性亲和力，解离常数（K(d)）在纳摩尔范围内。基于 LPS 结合适体的序列和二级结构分析，选择了对 LPS 具有最高亲和力的适体（即 B2），在金表面构建了阻抗生物传感器。与传统的鲎变形细胞溶解物（LAL）测定法相比，开发的电化学适体传感器在 LPS 浓度为 0.01 至 1 ng/mL 的线性检测范围内具有出色的灵敏度和特异性，并且检测时间显著缩短。
