Motility of Coupled Swimmers

双人游泳者的运动能力

• 批准号: 254569270
• 负责人: Professor Dr. Michael Mertig
• 金额: --
• 依托单位: Professur für Physikalische Chemie, Mess- und Sensortechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/254569270?language=en
• 关键词: Motility; Coupled; Swimmers

We will harness advanced methods of DNA technology to construct coupled thermo-phoretic swimmers and to investigate their motility.A unique feature of our approach is a built-in force sensor which will allow to measure forces involved in the propulsion of coupled swimmers in situ, and thus, to derive a physical description of the self-propelled motion. The force sensor is realized by coupling of actively driven Janus particles and passive cargo particles by means of a double-stranded DNA molecule. Since the force-distance relation of DNA is well known, this setup allows deriving local forces directly by measuring the distance between the particles, when the whole ensemble is propelled.Laser-induced propulsion will be realized using Janus particles as active swimmers. The Janus particles are polystyrene microspheres with a thin gold layer on one hemisphere, around which an asymmetric temperature, and thus, flow field is generated when they are irradiated by laser light.DNA technology easily allows varying the length of the linker between the active swimmer and the cargo particle. In this way, arrangements of coupled swimmers will be constructed, where the cargo is positioned within or outside of the laser-induced flow field which allows to study the impact of the cargo on the local flow field. By varying both the input power of laser irradiation and the counteracting force created by the Stokes drag of the cargo particle, we plan to derive important physical parameters of the system, such as, e.g. stall force or rotational diffusion time of the Janus particle.In preliminary experiments we already got evidence that the rotational diffusion can be reduced by dragging cargo. Here we plan to investigate this behavior in detail, because the suppression of rotational diffusion is one important requirement for a directed movement of swimmers. In this context, we also plan to construct and to apply linkers with much higher mechanical stiffness by means of DNA origami technique.In the later state of the planned project, we will focus on the investigation of the motility of complex swimmers, where a varying number of coupled active Janus particles can be driven simultaneously. Here the goal is to determine, how both velocity and generated force depend on the number of driven particles. This task will allow comparing the behavior of artificial swimmers to biological systems, for example to the well-studied motility of microtubule-associated molecular motors.We plan a sustainable collaboration with our long-term partners from University Leipzig - with the group of Frank Cichos in terms of the measurements on their dark-field setup and with the group of Klaus Kroy concerning the theoretical description of the swimmer motility. The results are expected to facilitate the creation of new artificial swimmers.

我们将利用DNA技术的先进方法来构建双人温磷游泳者并调查他们的动机。我们方法的一个独特功能是内置力传感器，它将允许在现场测量双人游泳者推进时所涉及的力，从而得出自行式运动的物理描述。力传感器由主动驱动的Janus粒子和被动的货物粒子通过双链DNA分子耦合而实现。由于DNA的力-距离关系是众所周知的，当整个系综被推进时，这种设置允许通过测量粒子之间的距离直接推导局部力。利用Janus粒子作为主动游泳者将实现激光诱导的推进。Janus颗粒是聚苯乙烯微球，在一个半球上有一层薄薄的金层，其周围的温度不对称，因此当它们被激光照射时会产生流场。DNA技术很容易改变活跃的游泳者和货物颗粒之间的连接物的长度。通过这种方式，将构建耦合游泳者的布置，其中货物位于激光诱导的流场之内或之外，从而允许研究货物对局部流场的影响。通过改变激光照射的输入功率和货物粒子的斯托克斯阻力产生的反作用力，我们计划推导出系统的重要物理参数，如失速力或Janus粒子的旋转扩散时间。在初步实验中，我们已经得到了通过拖动货物可以减少旋转扩散的证据。在这里，我们计划详细研究这种行为，因为抑制旋转扩散是游泳者定向运动的一个重要要求。在此背景下，我们还计划通过DNA折纸技术来构建和应用具有更高机械刚度的连接件。在计划项目的后期，我们将重点研究复杂游泳者的运动性，其中不同数量的耦合活动Janus粒子可以同时驱动。这里的目标是确定速度和所产生的力如何取决于被驱动粒子的数量。这项任务将允许比较人工游泳者与生物系统的行为，例如与研究得很好的微管相关分子马达的运动性。我们计划与莱比锡大学的长期合作伙伴-Frank Cichos组在其暗场设置方面的测量方面，以及与Klaus Kroy组关于游泳者运动性的理论描述方面进行可持续的合作。这一结果有望为创造新的人工游泳者提供便利。