材料期刊网

核酸适配体（aptamer）是从人工合成的随机单链 DNA（ssDNA）或 RNA 文库中筛选得到的，能够高亲和力、高特异性地与靶标结合的 ssDNA或 RNA。核酸适配体的靶标范围广，可包括小分子、蛋白质、细胞、微生物等多种靶标。其中以细胞为靶标的适配体在生物感应、分子成像、医学诊断、药物传输和疾病治疗等领域有很大的应用潜能。但全细胞的核酸适配体筛选过程复杂，筛选难度大，筛选的适配体性能不佳是导致目前可用的适配体非常有限的主要原因。由于细胞表面蛋白质在提取纯化过程中分子结构和形态会发生改变，故以膜表面蛋白质为靶标筛选的适配体很难应用于识别整体细胞。以全细胞为靶标的核酸适配体筛选则不需要准确了解细胞表面的分子结构，筛选过程中可保持细胞的天然状态，以全细胞为靶标筛选出的核酸适配体有望直接用于全细胞识别。本文总结了2008～2015年全细胞的核酸适配体筛选的研究进展，介绍了靶细胞的分类、核酸库的设计、筛选条件和方法以及核酸适配体的亲和力表征方法等。并列出全细胞靶标的核酸适配体序列。

Aptamers are single stranded DNA( ssDNA)or RNA that may bind to small mole-cules,proteins,cells,microorganisms,and other targets. Typically,aptamers are generated by a selection process referred to as systematic evolution of ligands by exponential enrichment ( SELEX). Aptamers that bind with high affinity and specificity to proteins that reside on the cell surface have potential utility in the fields of biosenser,molecular imaging,medical diagno-sis,drug delivery,and disease treatment. However,till now,available aptamers are very limit-ed mainly due to the complex and difficulty screening of aptamer and their poor properties. Using purified cell surface proteins as target has the disadvantage of changing structure. When target proteins are present in a modified state,the isolated aptamers might not recognize the natural structure of some proteins. Aptamers screening targeting whole cell has the potential to be used as cell probe for directing whole cell analysis. It does not need to understand the molecular structure of the cell surface protein and maintain the natural state of cells in the screening process. This review mainly focuses on the advances of aptamer selection for whole cell from 2008 to 2015. The contents include the classification of target cells,design of library, methods for cell-ssDNA complex separation and affinity characterization. The sequences of aptamers reported are listed.