Wetting of bio-inspired, stimulus-responsive polymer surfaces by lipid vesicles

脂质囊泡润湿仿生刺激响应聚合物表面

• 批准号: 422801301
• 负责人: Professor Dr. Marcus Müller
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/422801301?language=en
• 关键词: Wetting; bio; inspired; stimulus; responsive

Analog to liquid drops, the shape of a vesicle is dictated by its enclosed volume, the membrane-substrate interaction (interface potential), and the properties of the interface (membrane) between the interior and exterior. Unique to wetting by vesicles is the importance of the membrane’s intrinsic bending rigidity and the buoyancy of the enclosed liquid.The experimental Tanaka team has established a bio-inspired polymer brush platform, capable of switching the adhesion of vesicles, and has monitored the large-scale vesicle shape by 3D confocal microscopy. This setup will be complemented by a micro-interferometry technique, providing information about the local geometry of the edge of the brush-vesicle contact zone. The theoretical Müller team has implemented a highly coarse-grained particle model of the switchable polymer brush and a triangulated Helfrich-Hamiltonian of the thin lipid membrane in a parallel, GPU-accelerated MD program and has generalized the Helfrich description to include a finite-ranged interface potential and buoyancy. In the new period, they will explicitly include solvents to account for viscous dissipation.Both teams will jointly investigate the dynamic change of vesicle shapes in response to a switch in adhesion and the adaptation of the brush to the contact with a vesicle by time-dependent measurements of the vesicle geometry. Thermodynamic forces (bending energy, adhesion, and buoyancy) and dissipation mechanisms (e.g., dissipation at the contact zone and of the surrounding liquids) exhibit different dependencies on the vesicle size, whose systematic variation will allow us to distinguish between different dissipation mechanisms and aid the comparison between experiment and simulation. Additionally, we will consider how transport of membrane species (e.g., positively charged lipids, binding to -COOH groups of the brush) toward the contact zone influences the dynamics of the vesicle. This line of study will be extended to heterogeneous substrates, where a wettability gradient may result in a pining of the contact zone or a gradual variation may induce a translation and spreading of the vesicle. We will also study time-periodic switches of the wettability and wettability gradients that move over the substrate. The lateral motion of vesicles will give rise to additional dynamics such as e.g. sliding or rolling motion/tank-treading of the vesicle.

与液滴类似，囊泡的形状由其封闭体积、膜-基质相互作用（界面电位）以及内部和外部之间的界面（膜）特性决定，这是囊泡润湿的独特之处。实验田中团队建立了一个仿生聚合物刷平台，能够切换囊泡的粘附，并具有通过 3D 共焦显微镜监测大尺度囊泡形状，该装置将辅以微干涉测量技术，提供有关刷状囊泡接触区边缘的局部几何形状的信息。 -并行 GPU 加速 MD 程序中可切换聚合物刷的颗粒模型和薄脂膜的三角 Helfrich-Hamiltonian 模型，并推广了 Helfrich描述包括有限范围的界面电势和浮力。在新时期，他们将明确包括考虑粘性耗散的溶剂。两个团队将共同研究囊泡形状响应于粘附和适应的变化的动态变化。通过随时间测量囊泡几何形状的热力学力（弯曲能、粘附力和浮力）和耗散机制，将刷子与囊泡接触。 （例如，接触区和周围液体的耗散）对囊泡大小表现出不同的依赖性，其系统变化将使我们能够区分不同的耗散机制并帮助实验和模拟之间的比较此外，我们将考虑如何传输。膜种类（例如，带正电的脂质，与刷子的-COOH基团结合）朝向接触区的变化会影响囊泡的动力学，该研究将扩展到异质基质。润湿性梯度可能会导致接触区的钉扎，或者逐渐变化可能会导致囊泡的平移和扩散。我们还将研究在基底上移动的润湿性和润湿性梯度的时间周期切换。将产生额外的动力学，例如囊泡的滑动或滚动运动/坦克踩踏。