Abstract：
Target-immobilized magnetic beads-based Systematic Evolution of Ligands by Exponential Enrichment (target-immobilized Mag-SELEX) has emerged as a powerful tool for aptamer selection owing to its convenience, efficiency, and versatility. However, in this study we systematically investigated non-specific adsorption in target-immobilized Mag-SELEX and found that the non-specific adsorption of the oligonucleotides to target-labeled magnetic beads was comparable to that of the screening libraries, indicating a substantial portion of captured sequences likely stem from non-specific adsorption. Longer nucleic acid sequences (80 nt and above, such as polyA80 and yeast tRNA) were found to attenuate this non-specific adsorption, with more complex higher-order structures demonstrating greater efficacy, while dNTP and short sequences such as primer sequences (20 nt), polyT(59), or polyA(59), did not possess this capability. Various evidence suggested that hydrophobic interactions and other weak interactions may be the primary underlying cause of non-specific adsorption. Additionally, surface modification of magnetic beads with polar molecule polyethylene glycol (PEG) also yielded a significant reduction in non-specific adsorption. In conclusion, our research underscores the critical importance of closely monitoring non-specific adsorption in target-immobilized Mag-SELEX.
摘要：
基于目标固定磁珠的配体通过指数富集的系统进化（目标固定的Mag-SELEX）由于其便利性而成为适体选择的强大工具，效率,和多功能性。然而,在这项研究中，我们系统地研究了固定目标的Mag-SELEX中的非特异性吸附，发现寡核苷酸对目标标记的磁珠的非特异性吸附与筛选文库相当，表明捕获序列的很大一部分可能源于非特异性吸附。更长的核酸序列（80nt及以上，如polyA80和酵母tRNA)被发现减弱这种非特异性吸附，更复杂的高阶结构表现出更大的功效，而dNTP和短序列如引物序列（20nt），polyT（59），或polyA（59），没有这个能力。各种证据表明，疏水相互作用和其他弱相互作用可能是非特异性吸附的主要根本原因。此外,用极性分子聚乙二醇（PEG）对磁珠进行表面改性也显着降低了非特异性吸附。总之,我们的研究强调了密切监测目标固定化Mag-SELEX中非特异性吸附的重要性。
