School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong Province 250353, China.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):2091-2099. doi: 10.1021/acsami.0c20211. Epub 2020 Dec 31.
Though phospholipids possess chiral centers, their chiral aggregation within bilayer cell membranes has seldom been referred and recognized. Insight into the chirality at higher levels in artificial molecular bilayer assemblies such as vesicles or liposomes is important to better understand biomembrane functions. In this work, we illustrate the fabrication of chiral vesicles with photoresponsive supramolecular chirality and structural transformation property. Cholesterol was conjugated to azobenzene via different spacers, of which molecular chirality underwent transfer to supramolecular level upon aggregation in water. The resultant building block self-assembled into unilamellar vesicles that could respond to light irradiation by showing reversible extension/contraction behavior. Such "breathing" behavior was accompanied with supramolecular chirality inversion from M- to P-handedness, confirmed by the solid-state crystal structure and electronic circular dichroism spectra based on density functional theory. The vesicle membrane behaves as a matrix to accommodate guest molecules via aromatic interactions, which significantly elevated the UV light resistance with respect to the structural and supramolecular chirality transformation. This work offers an unprecedented rational control over supramolecular chirality using photoresponsiveness in vesicular membranes.
尽管磷脂具有手性中心，但它们在双层细胞膜内的手性聚集很少被提及和认识。了解人工分子双层组装体（如囊泡或脂质体）中更高层次的手性对于更好地理解生物膜功能非常重要。在这项工作中，我们展示了具有光响应超分子手性和结构转变特性的手性囊泡的制备。胆固醇通过不同的间隔物与偶氮苯连接，其中分子手性在水中聚集时会转移到超分子水平。所得的构建块自组装成单层囊泡，通过光照射可以表现出可逆的延伸/收缩行为。这种“呼吸”行为伴随着从 M 手性到 P 手性的超分子手性反转，通过基于密度泛函理论的固态晶体结构和电子圆二色光谱得到证实。囊泡膜作为基质，通过芳香相互作用容纳客体分子，这大大提高了对结构和超分子手性转变的紫外线抗性。这项工作为使用囊泡膜中的光响应来对手性进行前所未有的合理控制提供了可能。
