High affinity binders targeting specific cell surface proteins are vital for development of basic and applied biosciences. However, despite sustained efforts to generate such binders by chemicals and antibodies, there are still many cell surface proteins that lack high affinity binders. Nucleic acid aptamers have potential as binding molecules for cell surface proteins, because they form distinct structures that have high affinity and specificity for a wide range of targets. Aptamers are isolated from large combinatorial libraries using a unique iterative selection-amplification process known as systematic evolution of ligands by exponential enrichment (SELEX). Among advantages of this method, purified and complex heterogeneous targets, such as bacteria, viruses, and whole-living cells, can be used for selection of aptamers. Moreover, SELEX allows generation of cell-surface-specific aptamers without prior knowledge of expression profiles in target cells. Therefore, the technology has been widely used as a valid and feasible method to generate aptamers binding to cell surface proteins with intact structure. Herein, this review summarizes and updates iconic SELEX technologies that target membrane proteins.

靶向特定细胞表面蛋白的高亲和力结合剂对于基础和应用生物科学的发展至关重要。然而，尽管通过化学物和抗体不断努力产生这种结合物，但是仍然有许多细胞表面蛋白缺乏高亲和力结合物。核酸适体具有作为细胞表面蛋白结合分子的潜力，因为它们形成对多种靶标具有高亲和力和特异性的独特结构。使用独特的迭代选择-扩增过程（称为通过指数富集的配体系统进化）从大型组合文库中分离适体。在该方法的优点中，纯化的和复杂的异质靶标（例如细菌，病毒和全生命细胞）可用于选择适体。而且，SELEX可以产生细胞表面特异性适体，而无需事先了解靶细胞中的表达谱。因此，该技术已被广泛用作生成与完整结构的细胞表面蛋白结合的适体的有效方法。在此，本综述总结并更新了靶向膜蛋白的标志性SELEX技术。