Swimming Behaviour of a Sperm-Flagella Driven Micro-Bio-Robot: From Fundamental Studies to Biomedical Applications

精子鞭毛驱动的微生物机器人的游泳行为：从基础研究到生物医学应用

• 批准号: 254852158
• 负责人: Professor Dr. Oliver G. Schmidt
• 金额: --
• 依托单位: MIRA - Institute for Biomedical Technology and Technical Medicine
• 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 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/254852158?language=en
• 关键词: Swimming; Behaviour; Sperm; Flagella; Driven

Hybrid microswimmers which contain a biological power source for the propulsion of artificially synthetized microstructures is an appealing approach for the controlled actuation on the small scale. In particular, biological swimmers offer a biocompatible solution for the motion and cargo delivery in the low Reynolds number regime. Our approach to a hybrid microswimmer consists of ferromagnetic nanomembranes which roll up into microtubes and capture single bovine spermatozoa. The single motile cell is able to propel the rolled up microtube forward while an external magnetic field can be used to guide the sperm-flagella driven micro-bio-robot to desired locations. As our project title reveals, the aim of this work is, on the one hand to gain a deeper understanding of sperm motion in the confinement of microtubes, on the other hand to go step by step towards biomedical applications which the sperm-driven micro-bio-robots are promising for. The main goal of the fundamental studies of this project is to understand the biophysical dynamics of sperm-driven micro-bio-robots in more realistic environments. This includes higher viscosity media, non-Newtonian fluids and other conditions that are given in the natural surroundings of spermatozoa and also in general in body fluids. Furthermore, we will investigate the influence of stimuli on the sperm-driven micro-bio-robots and explore their suitability as control mechanisms. Taxis mechanisms such as rheotaxis (orientation against fluid flow) and thigmotaxis (interaction with surfaces) will be in the focus of our investigations. Especially interesting and challenging in the taxis-based context will be the interplay of the different control mechanisms of the sperm-driven micro-bio-robots. For instance, what is the minimum magnetic field strength needed to overrule the rheotactic orientation, will the sperm-driven micro-bio-robot reorient in the flow after the magnetic field is turned off? These and further questions will be addressed in this part of the project. Furthermore, we plan to study the interaction of the sperm-driven micro-bio-robots with the cumulus cell layer, which is a viscous cell layer which the spermatozoa encounter on their way to the oocyte. Surface modifications of the microtubes will be implemented in order to degrade the cumulus cells locally and free the way to the oocyte. The potential of the sperm-driven micro-bio-robots to serve as active drug carriers will be explored. In summary, this will lead to important progress in the fundamental understanding of sperm motion but also be helpful towards applications of the sperm-driven micro-bio-robots in assisted reproduction or drug delivery.

以生物动力源为动力的混合型微泳者是实现小尺度受控驱动的一种有效途径。特别是，生物游泳者为低雷诺数区域的运动和货物运送提供了一种生物兼容的解决方案。我们的混合微泳器由铁磁性纳米膜组成，这些纳米膜卷成微管，捕获单个牛精子。单个活动细胞能够推动卷起的微管向前移动，而外部磁场可以引导精子鞭毛驱动的微型生物机器人到达期望的位置。正如我们的项目标题所揭示的那样，这项工作的目的一方面是为了更深入地了解精子在微管限制下的运动，另一方面是为了逐步走向精子驱动的微型生物机器人有望实现的生物医学应用。本项目基础研究的主要目标是了解精子驱动的微型生物机器人在更真实的环境中的生物物理动力学。这包括更高粘度的介质、非牛顿流体和其他条件，这些条件是在精子的自然环境中提供的，通常也在体液中提供。此外，我们将研究刺激对精子驱动的微型生物机器人的影响，并探索它们作为控制机制的适用性。趋向性机制，如趋流性(针对流体流动的方向)和趋厚性(与表面的相互作用)将是我们研究的重点。在以出租车为基础的背景下，特别有趣和具有挑战性的是精子驱动的微型生物机器人的不同控制机制之间的相互作用。例如，推翻流变取向所需的最小磁场强度是多少，精子驱动的微型生物机器人在磁场关闭后会在流动中重新定向吗？这些问题和其他问题将在该项目的这一部分中讨论。此外，我们计划研究精子驱动的微型生物机器人与卵丘细胞层的相互作用，卵丘细胞层是精子在进入卵母细胞的过程中遇到的一个粘性细胞层。将对微管进行表面修饰，以局部降解卵丘细胞，并释放通往卵母细胞的途径。将探索精子驱动的微型生物机器人作为主动药物载体的潜力。总之，这将导致对精子运动的基本了解的重要进展，也有助于精子驱动的微型生物机器人在辅助生殖或药物输送方面的应用。