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Redox-Driven In Situ Helix Reversal of Graphene-Based Hydrogels
ACS Nano ( IF 17.1 ) Pub Date : 2020-11-17 , DOI: 10.1021/acsnano.0c06938
Yaqian Zhang 1 , Minggao Qin 1 , Chao Xing 1 , Changli Zhao 1 , Xiaoqiu Dou 1 , Chuanliang Feng 1
Affiliation  

Controlling the handedness of dynamic helical nanostructures of supramolecular assemblies by external stimuli is of great fundamental significance with appealing morphology-dependent applications. Significantly, access to in situ chirality transformation of dynamic multistimuli-responsive systems can provide channels for real-time monitoring of the transfer processes in biological systems. However, efforts to achieve helix inversion in an all-gel-state and to comprehend the phenomena at a molecular scale are scarce. Herein, we introduce an example of supramolecular hydrogel in which graphene oxide (GO) incorporation leads to opposite helicity of the l-phenylalanine derivative (LPFEG) upon UV irradiation. The gelator modulates different degrees of packing that are responsible for the initial construction of right-handed nanofibers in GO surfaces and for the change in helix to preferred left-handedness in RGO surfaces caused by GO reduction. Specifically, LPFEG shows a mixture of right- and left-handed nanofibers with an appropriate exposure to UV light. A thermal-reversible transformation of chirality is also discovered in the supramolecular assemblies, allowing a dynamic and invertible flip of helicity upon heating and cooling. The morphology transformation makes the hybrid an ideal candidate for application in a precisely controlled drug delivery process. It can unexpectedly serve as a photosensitizer and a carrier for enantioselective absorption of specific chiral drugs enantiomer (l-dopa and S-naproxen sodium) and also exhibit on-demand drug release due to the helix reversal induced by light irradiation. Our results illustrate how the surface reactivity can direct the helical organization of adsorbed fibers, which in turn provide control over enantioselective absorption of chiral drug enantiomers, further giving rise to on-demand drug release due to handedness inversion upon UV irradiation.

中文翻译:

氧化还原驱动的石墨烯基水凝胶的原位螺旋逆转

通过有吸引力的形态学依赖的应用,通过外部刺激控制超分子组装体的动态螺旋纳米结构的惯用性具有重大的基础意义。重要的是,获得动态多重刺激响应系统的原位手性转化可为实时监测生物系统中的转移过程提供渠道。然而,在全凝胶状态下实现螺旋反转并在分子尺度上理解现象的努力很少。在这里,我们介绍一个超分子水凝胶的例子,其中氧化石墨烯(GO)的引入会导致l的相反螺旋度紫外线照射下的-苯丙氨酸衍生物(LPFEG)。胶凝剂可调节不同的堆积程度,这些堆积程度负责GO表面中右手纳米纤维的初始构造,以及导致GO还原导致RGO表面中的螺旋线变为首选左手性的原因。具体而言,LPFEG显示了右手和左手纳米纤维的混合物,并适当暴露于紫外线。在超分子组装体中还发现了手性的热可逆转变,从而在加热和冷却时允许螺旋性动态且可逆地翻转。形态转换使杂种成为精确控制药物递送过程中应用的理想候选者。它可以意外地用作光敏剂和特定手性药物对映异构体的对映选择性吸收的载体(1-多巴和S-萘普生钠)也由于光照射引起的螺旋反转而显示出按需药物释放。我们的结果说明了表面反应性如何引导吸附纤维的螺旋结构,进而提供了对手性药物对映异构体对映选择性吸收的控制,进而由于紫外线照射下的手性反转而进一步导致按需释放药物。
更新日期:2020-12-22
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