College of Science, Northeastern University, Shenyang 110004, China.
Anal Chem. 2021 Aug 24;93(33):11515-11524. doi: 10.1021/acs.analchem.1c01903. Epub 2021 Aug 11.
Enantioselective identification of chiral molecules is important for biomedical and pharmaceutical research. However, owing to identical molecular formulas and chemical properties of enantiomers, signal transduction and amplification are still the two major challenges in chiral sensing. In this study, we developed an enantioselective membrane by integrating homochiral metal-organic frameworks (MOFs) with nanochannels for the sensitive identification and quantification of chiral compounds. The membrane was designed using a TiO nanochannel membrane (TiNM) as the metal ion precursor of MOFs (using MIL-125(Ti)) and incorporating l-glutamine (l-Glu) into the framework of MIL-125(Ti). Using 3,4-dihydroxyphenylalanine (DOPA) as the model analyte, the as-prepared homochiral l-Glu/MIL-125(Ti)/TiNM exhibits a remarkable chiral recognition to d-DOPA than l-DOPA. More importantly, benefiting from the highly enlarged surface area and confinement effect provided by the MOFs-in-nanochannel architecture, the discrimination for chiral recognition is largely amplified through the chelation interaction of Fenton-like activity of Fe onto DOPA. Using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as the substrate, the positively charged ABTS product via Fenton-like reaction induces significant ionic transport changes in nanochannels, which in turn provides information about chiral recognition. This innovative signal amplification strategy on homochiral nanochannels might pave a new way for sensitive monitoring and chiral recognition.
手性分子的对映选择性识别对于生物医学和药物研究很重要。然而，由于对映异构体具有相同的分子式和化学性质，因此信号转导和放大仍然是手性传感的两个主要挑战。在这项研究中，我们通过将手性金属有机骨架（MOFs）与纳米通道集成在一起，开发了一种对映选择性膜，用于灵敏识别和定量手性化合物。该膜的设计使用 TiO2 纳米通道膜（TiNM）作为 MOFs（使用 MIL-125（Ti））的金属离子前体，并将 l-谷氨酰胺（l-Glu）掺入 MIL-125（Ti）的骨架中。使用 3,4-二羟基苯丙氨酸（DOPA）作为模型分析物，所制备的手性 l-Glu/MIL-125（Ti）/TiNM 对 d-DOPA 表现出明显的手性识别，而对 l-DOPA 则没有。更重要的是，得益于 MOFs-in-nanochannel 结构提供的高放大表面积和限制效应，手性识别的区分度通过 Fenton 样活性的 Fe 与 DOPA 的螯合相互作用得到了极大放大。使用 2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）作为底物，通过 Fenton 样反应产生的带正电荷的 ABTS 产物会引起纳米通道中离子传输的明显变化，从而提供有关手性识别的信息。这种在手性纳米通道上进行的创新信号放大策略可能为敏感监测和手性识别开辟新途径。
