Sculpting the shapes of giant unilamellar vesicles using isotropic–nematic–isotropic phase cycles
Sculpting the shapes of giant unilamellar vesicles using isotropic–nematic–isotropic phase cycles
复制标题
使用各向同性-向列-各向同性相循环塑造巨型单层囊泡的形状
DOI：
10.1039/d1sm00910a
复制
发表时间：
2021
期刊：
影响因子：
3.4
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
--
作者：
Jani, Purvil;Nayani, Karthik;Abbott, Nicholas L.
了解软物质如何响应机械相互作用而变形对于功能合成材料的设计以及生物组件行为的阐明至关重要。在这里，我们探索如何利用向列相 (N) 和各向同性相 (I) 之间的热诱导转变循环对巨型单层囊泡 (GUV) 的分散体施加循环弹性应力，从而演化 GUV 的形状和性能。通过发现溶致发色液晶色甘酸二钠的 I-N-I 相变，当通过中间柱状 (M) 相进行时，可以最大限度地减少相前沿上的 GUV 向限制表面的传输，从而实现了测量。 I 到 N 相变将球形 GUV 应变为纺锤状形状，并且 GUV 内部体积流出，随后的 N 到 I 相变产生了一系列复杂的 GUV 形状，包括口形、梨形和哑铃形，这些形状取决于 N 相的应变程度。观察到最高应变的 GUV 形成芽（子囊泡），我们发现，通过 I-N-I-N 相变循环，芽芽（子囊泡）通过颈部连接到母体囊泡。其他实验证实，GUV 周围相的弹性变化而不是膜的热膨胀导致了形状转变，并且可以从 GUV 形状的双层耦合模型来理解生成口细胞的 I-N-I 转变。总体而言，这些观察结果增进了我们对如何调节液晶弹性应力以演化软生物组件形状的理解，并为工程合成软物质提供了新方法。
Understanding how soft matter deforms in response to mechanical interactions is central to the design of functional synthetic materials as well as elucidation of the behaviors of biological assemblies. Here we explore how cycles of thermally induced transitions between nematic (N) and isotropic (I) phases can be used to exert cyclical elastic stresses on dispersions of giant unilamellar vesicles (GUVs) and thereby evolve GUV shape and properties. The measurements were enabled by the finding that I–N–I phase transitions of the lyotropic chromonic liquid crystal disodium cromoglycate, when conducted via an intermediate columnar (M) phase, minimized transport of GUVs on phase fronts to confining surfaces. Whereas I to N phase transitions strained spherical GUVs into spindle-like shapes, with an efflux of GUV internal volume, subsequent N to I transitions generated a range of complex GUV shapes, including stomatocyte, pear- and dumbbell-like shapes that depended on the extent of strain in the N phase. The highest strained GUVs were observed to form buds (daughter vesicles) that we show, via a cycle of I–N–I–N phase transitions, are connected via a neck to the parent vesicle. Additional experiments established that changes in elasticity of the phase surrounding the GUVs and not thermal expansion of membranes were responsible for the shape transitions, and that I–N–I transformations that generate stomatocytes can be understood from the Bilayer-Coupling model of GUV shapes. Overall, these observations advance our understanding of how LC elastic stresses can be regulated to evolve the shapes of soft biological assemblies as well as provide new approaches for engineering synthetic soft matter.