Chirality is a ubiquitous phenomenon in nature, but enantiomers exhibit different pharmacological activities and toxicological effects. Therefore, Chiral recognition plays a pivotal role in various fields such as life sciences, chemical synthesis, drug development, and materials science. The synthesis of novel chiral composites with well-defined loading capabilities and ordered structures holds significant potential for electrochemical chiral recognition applications. However, the design of selective and stable electrochemical chiral recognition materials remains a challenging task. In this work, we construct a simple and rapid electrochemical sensing platform for tryptophan (Trp) enantiomer recognition using cyclodextrin-modified microporous organic network as chiral recognition agent. CD-MON with chiral microenvironment was prepared by Sonogashira-Hagihara coupling reaction of the chiral molecule heptyl-6-iodo-6-deoxyβ-cyclodextrin and 1, 4-Diethynylbenzene. The adhesion of BSA makes CD-MON firmly fixed on the electrode surface, and as a chiral protein, it can improve the chiral recognition ability through synergistic effect. Chiral amino acids are in full contact with the chiral microenvironment during pore conduction of MON, and L-Trp is more stably bound to CD-MON/BSA due to steric hindrance, host-guest recognition and hydrogen bonding. Therefore, the electrochemical sensor can effectively identify tryptophan enantiomers (I/I = 2.02), and it exhibits a detection limit of 2.6 μM for L-Trp. UV–Vis spectroscopy confirmed the adsorption capacity of CD-MON towards tryptophan enantiomers in agreement with electrochemistry results. The prepared chiral sensor has excellent stability, reproducibility (RSD = 3.7%) and selectivity, realizes the quantitative detection of single isomer in tryptophan racemic and quantitative analysis in real samples with 94.0%–101.0% recovery. This work represents the first application of MON in chiral electrochemistry which expands the application scope of chiral sensors and holds great significance in separation science and electrochemical sensing.

中文翻译：

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基于环糊精的微孔有机网络用于识别氨基酸对映体的电化学手性传感器


手性是自然界中普遍存在的现象，但对映体表现出不同的药理活性和毒理作用。因此，手性识别在生命科学、化学合成、药物开发、材料科学等各个领域发挥着举足轻重的作用。具有明确负载能力和有序结构的新型手性复合材料的合成在电化学手性识别应用中具有巨大的潜力。然而，选择性且稳定的电化学手性识别材料的设计仍然是一项具有挑战性的任务。在这项工作中，我们使用环糊精修饰的微孔有机网络作为手性识别剂，构建了一个简单快速的电化学传感平台，用于色氨酸（Trp）对映体识别。通过手性分子庚基-6-碘-6-脱氧β-环糊精与1, 4-二乙炔基苯的Sonogashira-Hagihara偶联反应制备了具有手性微环境的CD-MON。 BSA的粘附力使得CD-MON牢固地固定在电极表面，并且作为手性蛋白，可以通过协同作用提高手性识别能力。 MON的孔道传导过程中手性氨基酸与手性微环境充分接触，L-Trp由于空间位阻、主客体识别和氢键作用而更稳定地与CD-MON/BSA结合。因此，电化学传感器可以有效识别色氨酸对映体（I/I = 2.02），并且对 L-Trp 的检测限为 2.6 μM。紫外-可见光谱证实了 CD-MON 对色氨酸对映体的吸附能力，与电化学结果一致。制备的手性传感器具有优异的稳定性、重现性（RSD = 3.7%）和选择性，实现了色氨酸消旋体中单一异构体的定量检测和实际样品中的定量分析，回收率94.0%~101.0%。该工作代表了MON在手性电化学中的首次应用，拓展了手性传感器的应用范围，对分离科学和电化学传感具有重要意义。