核酸适配体(aptamer)是通过指数富集配体系统进化技术(SELEX)筛选的能够以高亲和力和高特异性识别靶标分子或细胞的核糖核酸(RNA)和单链脱氧核糖核酸(ssDNA)。作为化学抗体,核酸适配体的制备和合成比抗体的成本更低。核酸适配体的靶标范围极其广泛,包括小分子、生物大分子、细菌和细胞等。针对细菌靶标筛选的适配体,目前主要应用于食品、医药和环境中的细菌检测。细菌的核酸适配体筛选可以通过离心法将菌体-适配体复合物与游离的适配体分离,并通过荧光成像、荧光光谱分析、流式细胞仪分选、DNA捕获元件、酶联适配体分析等方法表征适配体与靶标的相互作用。筛选出的适配体可结合生物、化学检测方法用于细菌检测。本文介绍了细菌适配体的筛选和表征方法以及基于适配体的检测方法的最新进展,分析了不同检测方法的利弊,并列出了2011~2015年筛选的细菌的核酸适配体。
Aptamers are RNA or singal stranded DNA(ssDNA),which are selected by systematic evolution of ligands by exponential enrichment(SELEX). Compared to antibodies,aptamers as chemical antibodies are artificially synthesized with low cost. They can bind a wide range of targets,including small molecules,large biological molecules,bacteria and cells. Aptamers targeting bacteria have the potential to be used for pathogen detection in food,medicine and environment. To select aptamers with high affinity to bacteria,centrifugation is mostly used.Binding affinity can be estimated by fluorescence imaging,fluorescence spectra,flow cytometry,DNA capture element(DCE)and enzyme-linked aptamers sorbent assay(ELASA). Selected aptamers combined with biological and chemical analysis methods can be used in bacteria detection. This article introduces the latest development in aptamer selection,characterization and application for bacteria detection and summarizes the aptamers for bacteria from 2011 to2015.