Yang Xiao-Rong, Song Xiao-Dong, Zhu Han-Yan, Cheng Chang-Jing, Yu Hai-Rong, Zhang Huai-Hao
College of Chemistry and Environment Protection Engineering, Southwest Minzu University, Chengdu, Sichuan 610041, P. R. China.
College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, P. R. China.
ACS Appl Bio Mater. 2018 Oct 15;1(4):1074-1083. doi: 10.1021/acsabm.8b00294. Epub 2018 Sep 13.
Multifunctional graphene oxide nanocomposites simultaneously possessing high enantioselectivity, excellent thermosensitivity, and magnetism demonstrate great application potentials in direct enantioseparation. We herein report one novel smart graphene oxide nanocomposite (MGO@PNG-CD) with high enantioselectivity, excellent thermosensitivity, and magnetism for highly efficient chiral identification and enantioseparation of tryptophan enantiomers. The MGO@PNG-CD is composed of graphene oxide nanosheets with immobilized superparamagnetic FeO nanoparticles and grafted PNG-CD smart polymer brushes. The PNG-CD is made up of poly(-isopropylacrylamide--glycidyl methacrylate) (PNG) chains with numerous appended β-cyclodextrin (β-CD) units, which play a significant role in effective chiral discrimination and resolution of -tryptophan (-Trp). The β-CD units serve as chiral selectors capable of selectively recognizing and binding -tryptophan (-Trp) into their cavities to form stable host-guest inclusion complexes of β-CD/-Trp. The PNIPAM chains in PNG act as a microenvironmental adjustor for the inclusion constants of β-CD/-Trp complexes. The resulted MGO@PNG-CD demonstrates high thermosensitive enantioselectivity toward -Trp over -Trp based on the chiral discrimination ability of β-CD toward -Trp and the thermosensitive volume phase transition of PNIPAM chains. Operating temperature and initial concentrations of -Trp are two significant factors affecting the separation efficiency of -Trp enantiomers. Moreover, the MGO@PNG-CD also displays satisfactory recycling and convenient magnetic separability from enantiomeric solution. Such a multifunctional graphene oxide nanocomposite developed in this study can serve as a high-performance nanoselector for highly efficient chiral recognition and enantioseparation of various chiral compounds.
同时具有高对映选择性、优异热敏感性和磁性的多功能氧化石墨烯纳米复合材料在直接对映体分离中展现出巨大的应用潜力。我们在此报告一种新型智能氧化石墨烯纳米复合材料（MGO@PNG-CD），它具有高对映选择性、优异热敏感性和磁性，用于高效手性识别和色氨酸对映体的对映体分离。MGO@PNG-CD由固定有超顺磁性FeO纳米颗粒并接枝有PNG-CD智能聚合物刷的氧化石墨烯纳米片组成。PNG-CD由带有众多附加β-环糊精（β-CD）单元的聚（N-异丙基丙烯酰胺-co-甲基丙烯酸缩水甘油酯）（PNG）链构成，这些单元在有效手性识别和拆分L-色氨酸（L-Trp）中起重要作用。β-CD单元作为手性选择剂，能够选择性地识别L-色氨酸（L-Trp）并将其结合到它们的空腔中，形成稳定的β-CD/L-Trp主客体包合物。PNG中的聚N-异丙基丙烯酰胺（PNIPAM）链作为β-CD/L-Trp复合物包合常数的微环境调节剂。基于β-CD对L-Trp的手性识别能力和PNIPAM链的热敏体积相转变，所得的MGO@PNG-CD对L-Trp比对映体D-Trp表现出高热敏对映选择性。操作温度和L-Trp的初始浓度是影响L-Trp对映体分离效率的两个重要因素。此外，MGO@PNG-CD还显示出令人满意的循环利用性以及从对映体溶液中方便的磁分离性。本研究中开发的这种多功能氧化石墨烯纳米复合材料可作为一种高性能纳米选择剂，用于各种手性化合物的高效手性识别和对映体分离。
