核酸适配体做为新型分子探针，是生物分析、食品和环境检测、疾病诊疗、核酸药物的研究热点之一，具有明显的交叉学科特色和产生经济效益的巨大潜力。核酸适配体的高效筛选是最难啃的骨头和瓶颈，国内外都没有取得明显突破。通过十年的筛选机理和策略研究，我们重新审视SELEX技术，认为筛选步骤中的多次PCR会造成偏性扩增放大和大量候选序列失真，直接导致筛选过程复杂、成功率低，而克隆测序或高通量测序则会引起序列漏选或海量数据的分析。.本项目提出全新的筛选理念和研究思路，建立“基于CE-MS的结合位点导向的核酸适配体Non-PCR直接测序筛选方法”。基于毛细管电泳高效分离“靶标-核酸”复合物，结合高分辨质谱，直接获得复合物中结合靶标位点的适配体区域片段及序列信息。摒弃SELEX中通用的多轮PCR扩增，实现适配体的高保真精准筛选。本研究将是对SELEX技术的重要修正，有望为适配体筛选带来突破。

Aptamers as novel molecular recognition probes, are one of the research hotspots in biology, food and environment analysis, disease diagnosis and treatment, nucleic acid drug development. Their related research has obvious interdisciplinary characteristics, a wide range of applications and great potential for producing economic benefits. At present, efficient screening of aptamers is a tough nut to crack and bottleneck, and there are no breakthroughs at home and abroad. Based on our ten years of research on aptamer screening mechanism and strategy, now is the time we reassess SELEX procedure. We think that in the screening steps of current SELEX design, multiple rounds PCR results in sequences partial amplification, so a large number of candidate sequences are distorted. Moreover, further plasmids based sequencing results in some sequences missing, and high-throughput sequencing results in the difficulty of mass data analysis. So PCR amplification is the key to affect screening complexity and low success rate. This project proposes a new methodology for aptamers screening, “CE-MS based binding site oriented Non-PCR direct sequencing method for aptamers screening”. The high efficiency separation of “target-nucleic acid” complex by capillary electrophoresis and high resolution mass spectrometry analysis as well as bioinformatics are combined to directly obtain the information of their binding site, binding region, and binding sequence, which abandons the multiple rounds PCR amplification, achieves high fidelity accurate screening of aptamers. The study will be an important revision of SELEX technology and is expected to bring a breakthrough for aptamers screening.