The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , 361005 , China.
Institute of Molecular Medicine, Renji Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , 200127 , China.
Anal Chem. 2019 Aug 20;91(16):10879-10886. doi: 10.1021/acs.analchem.9b02697. Epub 2019 Aug 9.
An enthalpy-driven ligand is an ideal probe for practical applications because of the formation of abundant specific bonds between the ligand and target, compared to an entropy-driven ligand with a similar Gibbs free energy change. However, there has been a lack of direct discovery strategy for identifying enthalpy-driven ligands. In this work, a molecular crowding SELEX (systematic evolution of ligands by exponential enrichment) strategy for discovering enthalpy-driven aptamers was developed to improve the affinity and selectivity of aptamers in complex samples. Three aptamer sequences were successfully evolved against a tumor biomarker protein, and all proved to be enthalpy-driven by thermodynamics analysis, establishing the feasibility of molecular crowding SELEX for effective discovery of enthalpy-driven aptamers. Further comparison of aptamers evolved from conventional SELEX in buffer and molecular crowding SELEX (SYL-H2C) revealed much higher affinity of SYL-H2C. With its improved thermodynamic properties, the enthalpy-driven SYL-H2C aptamer was able to detect circulating tumor cells in real cancer patient blood samples with excellent detection accuracy (10/10). The proposed molecular crowding screening strategy offers a promising direction for discovering robust binding probes for a great variety of biomedical applications.
由于与具有相似吉布斯自由能变化的熵驱动配体相比，配体与靶标之间形成了丰富的特定键，因此焓驱动配体是实际应用的理想探针。然而，一直缺乏直接发现识别焓驱动配体的策略。在这项工作中，开发了一种用于发现焓驱动适体的分子拥挤 SELEX（通过指数富集的配体系统进化）策略，以提高适体在复杂样品中的亲和力和选择性。针对肿瘤生物标志物蛋白成功地进化了三个适体序列，所有序列均通过热力学分析证明是焓驱动的，从而确立了分子拥挤 SELEX 用于有效发现焓驱动适体的可行性。进一步比较在缓冲液中和分子拥挤 SELEX（SYL-H2C）中从常规 SELEX 进化而来的适体，发现 SYL-H2C 的亲和力要高得多。具有改进的热力学性质，焓驱动的 SYL-H2C 适体能够以优异的检测准确性（10/10）检测到实际癌症患者血液样本中的循环肿瘤细胞。所提出的分子拥挤筛选策略为发现用于各种生物医学应用的强大结合探针提供了有希望的方向。
