AbstractThe authors describe a new kind of selection method (referred to as orientation selection) for improved screening for broad-spectrum lipopolysaccharides (LPSs) using unlabeled ssDNA aptamers. The method is based on the capture-SELEX technique using magnetic nanoparticles. LPS from Salmonella enterica serotype typhimurium was chosen as an exemplary target. Once the ssDNA library is preconcentrated to a certain degree, two Gram-negative bacteria were used as orientation molecules in the subsequent selection process. Using this strategy, one optimal aptamer ('EA7') was captured that has a high affinity (Kd = 102 ± 17 nM) for LPS and it was also confirmed that it can recognize three other bacterial LPSs. It is presumed that EA7 binds to the lipid A region of LPS. When using carboxyfluorescein labeled EA7, the observed fluorescence intensity and concentrations of four types of LPSs in drinking water are linearly correlated. The lower detection limit of the LPS is 3 ng·mL−1. Compared to multi-target mixed selection and conventional SELEX methods, the new orientation selection strategy produces results that are less uncertain. Graphical abstractAn improved orientation selection strategy in capture-SELEX procedures was developed to screen broad-spectrum aptamers against lipopolysaccharides by using magnetic nanoparticles. Two Gram-negative bacteria were used as orientation molecules after library preconcentrated to a certain degree.

中文翻译：

---

磁性纳米粒子基于capture-SELEX的脂多糖广谱适配体定向选择

摘要作者描述了一种新的选择方法（称为方向选择），用于使用未标记的 ssDNA 适体改进广谱脂多糖 (LPS) 的筛选。该方法基于使用磁性纳米粒子的捕获-SELEX 技术。来自沙门氏菌血清型鼠伤寒沙门氏菌的 LPS 被选为示例性目标。一旦 ssDNA 文库预浓缩到一定程度，两个革兰氏阴性菌就被用作后续选择过程中的定向分子。使用这种策略，捕获了一个对 LPS 具有高亲和力 (Kd = 102 ± 17 nM) 的最佳适体 ('EA7')，并且还证实它可以识别其他三种细菌 LPS。据推测，EA7 与 LPS 的脂质 A 区域结合。当使用标记为 EA7 的羧基荧光素时，饮用水中四种LPSs的观察荧光强度与浓度呈线性相关。LPS 的检测下限为 3 ng·mL-1。与多目标混合选择和传统 SELEX 方法相比，新的方向选择策略产生的结果不确定性较小。图形摘要开发了一种改进的捕获-SELEX 程序中的方向选择策略，以通过使用磁性纳米粒子筛选针对脂多糖的广谱适体。文库预浓缩到一定程度后，以两种革兰氏阴性菌为定向分子。新的方向选择策略产生的结果不确定性较小。图形摘要开发了一种改进的捕获-SELEX 程序中的方向选择策略，以通过使用磁性纳米粒子筛选针对脂多糖的广谱适体。文库预浓缩到一定程度后，以两种革兰氏阴性菌为定向分子。新的方向选择策略产生的结果不确定性较小。图形摘要开发了一种改进的捕获-SELEX 程序中的方向选择策略，以通过使用磁性纳米粒子筛选针对脂多糖的广谱适体。文库预浓缩到一定程度后，以两种革兰氏阴性菌为定向分子。