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上海交通大学自然科学研究院最新成果:动力学控制囊泡形态的研究

近期,ACS Nano发表了上海交通大学自然科学研究院及物理与天文系特别研究员姚振威和美国西北大学的合作者们共同完成的题为“Vesicle geometries enabled by dynamically trapped states”的论文(ACS Nano 10, 2287,2016), 报道了他们关于通过动力学方式控制囊泡形态的工作。

溶液中的基本单元分子自发组织成闭合的囊泡(vesicle)结构,这是生物学和材料科学中的一个基本过程。最终产生的囊泡结构作为基本功能单元,为药物运输和相关功能材料设计等提供了基础。理解囊泡构型背后的物理机制,对于高效制备不同形态的囊泡和最终在工程上实现其功能具有重要意义。最近,姚振威特别研究员和合作者们提出可通过设计动力学过程,以可控的方式驱动囊泡远离平衡态,最终锁定在各种稳定的形态,从而极大丰富囊泡构型。具体地,在粗粒化分子动力学模拟中,通过控制囊泡的脱水速率,囊泡展现出各种非平衡态构型。特别地,随着脱水过程,在结晶态囊泡表面开始出现多个局域平面结构(flattened areas),随后它们开始融合,最终将整个囊泡塑造成规则的多面体。对这些模拟结果的弹性理论分析,发现囊泡的晶态结构对这些特征性形变的形成具有关键的作用。与结晶态囊泡相比,脱水下的液态囊泡则呈现整体的形变。此项研究结果表明,通过设计动力学过程来操纵囊泡构型具有可控,效率高,构型更丰富等优点,对相关的囊泡自组装和工程操纵有一定的指导意义。

Abstract:
Understanding and controlling vesicle shapes is a
fundamental challenge in biophysics and materials design. In this
paper, we design dynamic protocols for enlarging the shape space of
both fluid and crystalline vesicles beyond the equilibrium zone. By
removing water from within the vesicle at different rates, we numerically
produced a series of dynamically trapped stable vesicle shapes for both
fluid and crystalline vesicles in a highly controllable fashion. In crystalline
vesicles that are continuously dehydrated, simulations show the initial
appearance of small flat areas over the surface of the vesicles that
ultimately merge to form fewer flat faces. In this way, the vesicles
transform from a fullerene-like shape into various faceted polyhedrons.
We perform analytical elasticity analysis to show that these salient
features are attributable to the crystalline nature of the vesicle. The
potential to use dynamic protocols, such as those used in this study, to
engineer vesicle shape transformations is helpful for exploiting the richness of vesicle geometries for desired applications.

通过动力学控制方式产生的典型结晶态囊泡构型

参考文献: J. Su, Z. Yao (co-first author), and M. Olvera de la Cruz, “Vesicle geometries enabled by dynamically trapped states”, ACS Nano 10, 2287 (2016)