AI 中文总结
本研究通过实验与模拟揭示DNA纳米星的堆积和刚度调控合成细胞膜上的分子动力学，为设计人工细胞横向流动性提供物理原理。
AI 中文摘要
DNA纳米结构正成为工程化合成细胞膜的可编程组件，然而其集体堆积和可变形性如何调控膜界面上的分子动力学仍知之甚少。在此，我们研究了具有可调刚度的DNA纳米星在脂质包被液滴上的堆积和迁移性。带负电的纳米星自发吸附到阳离子膜上，其界面堆积受体相DNA浓度和液滴尺寸的影响，二者共同决定了包封的纳米星数量。结合荧光恢复后光漂白实验与粗粒化模拟，我们揭示了刚性纳米星和柔性纳米星不同的堆积-动力学关系。对于刚性纳米星，随着界面堆积增加，扩散先逐渐减慢，随后急剧下降，接近与类堵塞行为一致的动态停滞状态。相比之下，在等效实验条件下，柔性纳米星系统地达到较低的界面堆积分数，并表现出表观迁移性的较弱下降。这一行为与其较弱的膜亲和力一致，这促进了与体相的吸附-脱附交换。当在模拟中抑制这种交换时，拥挤降低了两种纳米星类型的横向扩散，但产生了不同的致密构型：柔性纳米星发生强烈变形，而刚性纳米星基本保持其形状并形成互锁的齿轮状排列。纳米星吸附还阻碍了脂质扩散，而膜亲和力的差异导致不同的脂质移动分数。这些发现揭示了纳米星堆积与可变形性之间的相互作用如何调控膜界面上的分子传输，为调节人工细胞中的横向流动性和拥挤提供了物理设计原理。
英文摘要
DNA nanostructures are emerging as programmable components for engineering synthetic cell membranes, yet how their collective packing and deformability regulate molecular dynamics at membrane interfaces remains poorly understood. Here, we investigate the packing and mobility of DNA nanostars with tunable stiffness on lipid-coated droplets. The negatively charged nanostars spontaneously adsorb onto cationic membranes, and their interfacial packing is changed by the bulk DNA concentration and droplet size, which together determine the number of encapsulated nanostars. Combining fluorescence recovery after photobleaching experiments with coarse-grained simulations, we reveal distinct packing-dynamics relationships for rigid and soft nanostars. For rigid nanostars, diffusion first decreases gradually and then drops sharply with increasing interfacial packing, approaching a dynamically arrested state consistent with jamming-like behavior. In contrast, at equivalent experimental conditions, soft nanostars systematically reach lower interfacial packing fractions and show a weaker decrease in apparent mobility. This behavior is consistent with their weaker membrane affinity, which facilitates adsorption-desorption with the bulk. When this exchange is suppressed in simulations, crowding reduces the lateral diffusion of both nanostar types, but produces distinct dense configurations: soft nanostars become strongly deformed, whereas rigid nanostars largely retain their shape and form interlocked, gear-like arrangements. Nanostar adsorption also impedes lipid diffusion, while differences in membrane affinity result in distinct lipid mobile fractions. These findings reveal how the interplay between nanostar packing and deformability regulates molecular transport at membrane interfaces, providing a physical design principle for tuning lateral fluidity and crowding in artificial cells.
