中文摘要：

目的：研究SELEX技术用于筛选口腔致龋菌适配子的可行性。方法-化学合成长度为35mer的随机ssDNA文库，利用sE—LEX技术，分别以变形链球菌UA159（以下简称变链UA159）、乳杆菌和离心管作为靶物质，筛选适配子，不对称PCR扩增筛选产物，所得适配子进行克隆、测序，分析其二级结构，并对其二级结构进行了初步分析。结果：显示各个靶物质的筛选产物在第二轮筛选时就已经表现出具有特征性的二级结构。结论：SELEX技术可以用于口腔致龋菌适配子的筛选。

英文摘要：

Objective： To verify the feasibility of vitro selection of DNA aptamers against Streptococcus mutans UA159 by SELEX. Methods： Streptococcus Mutans UA159, Lactobacilli and 1.5mL centrifuge Tube are chosen to be target materials. And in vitro synthesized 35 mer random DNA library （10~z-~3 types of different DNAs） is subjected to selection using SELEX method against Streptococcus Mutans UA159, Lactobacilli and 1.5mL centrifuge Tube. The selected aptamers are amplified by asymmetric PCR, then cloned and sequenced. Finally, the structures of selected aptamers are analyzed. Results： The structure showed specific secondary structure shape characterized by their loops, bulges and hairpins in the second round. Conclusion： This sutdy shows the SELEX has the potential to be used as a selection tool to acquire aptamers with high affinity and specificity against oral bacteria.