Abstract: In order to quickly and efficiently screen target nucleic acid aptamers,it is urgent to establisha simple,efficient and visual new method for screening aptamers through exponentially enriched ligand system evolution technology(SELEX). In this paper,streptavidin(SA) was used as the target model,and its aptamer was screened and verified by the combination of localized surface plasmon resonance(LSPR)and capillary electrophoresis(CE).The results showed that in the first round of LSPR-SELEX,SA-bound aptamers(SBA) were screened,and the K_D value of SBA was 107 μmol/L by the Trace Drawer data analysis software of LSPR;In the second round of LSPR-SELEX,the K_D value of SBA was 98 nmol/L.The results above showed that only two rounds of screening by LSPR-SELEX technology increased the affinity of SBA by 1 000 times.Then,the screened SBA was verified by CE,and the results showed that the SBA aptamer had good affinity and specificity with its target SA.In summary,in view of the high efficiency of LSPR in separating and collecting target aptamers from the initial DNA library,LSPR-SELEX technology can provide a new method for the screening of nucleic acid aptamers.

Key words: Aptamers, LSPR-SELEX, Streptavidin, Capillary electrophoresis, K_D value

摘要： 为了快速、高效地筛选到靶标核酸适配体，急需通过指数富集的配基系统进化技术（SELEX）建立一种简便、高效和可视化筛选适配体的新方法。以链霉亲和素（SA）作为靶标模型，利用局域表面等离子体共振（LSPR）和毛细管电泳（CE）相结合的方法进行筛选和验证。结果显示，在第1轮LSPR-SELEX中，筛选到SA结合的适配体（SBA），并且通过LSPR的Trace Drawer数据分析软件计算出SBA的KD值为107 μmol/L；在第2轮LSPR-SELEX中，SBA的K_D值为98 nmol/L。结果表明，采用LSPR-SELEX技术经2轮筛选，使SBA的亲和力提高了1 000倍。随后，将筛选到的SBA 进行CE验证，结果显示， SBA适配体与其靶标SA具有良好的亲和性和特异性。综上，鉴于LSPR从初始DNA文库中分离和收集靶标适配体的高效性，LSPR-SELEX技术可用于核酸适配体的筛选。

关键词: 适配体, LSPR-SELEX, 链霉亲和素, 毛细管电泳, K_D值