Accelerated Degradation of Active Nanosystems by Biomolecular Motors

该奖项的研究目标是发展对活性纳米系统降解途径的理解。从宏观上看，汽车发动机不工作时会生锈，运转时会磨损。类似地，包含机械运动的活性纳米系统在激活时降解得更快。这个项目将利用分子穿梭机，由马达蛋白驱动蛋白驱动的纳米级运输系统，作为模型系统。将使用微制造的引导结构对移动的穿梭器施加限定的循环载荷，并且将使用光学显微镜观察穿梭器的中心部分的断裂。研究这些活性纳米结构内的降解探索了新的领域，因为分子穿梭系统太大，难以在原子水平上描述单键的力激活解离，但又太小，无法应用磨损和疲劳的宏观概念。因此，这些系统的纳米尺度上的中尺度视图是必需的，并将通过实验，模拟和理论相结合的发展。这项研究的结果将是在纳米尺度上对磨损和疲劳的更好理解。一方面，这种理解对于设计能够在预期寿命内正常工作而不发生故障的耐用器械至关重要。另一方面，降解产物可能会从系统中释放出来，类似于？刹车灰？由汽车的刹车片制成。为了评估活性纳米系统的潜在环境和毒理学影响，因此重要的是要了解纳米系统如何在其生命周期中演变并最终失败。虽然这项研究只是了解这些复杂过程的第一步，但它会吗？如果成功？为其他活性纳米系统的评估创建一个模板，并为理解这些降解过程提供一个基本的科学框架。

The research objective of this award is to develop an understanding of the degradation pathways of active nanosystems. At the macroscale, a car engine will rust when inactive, but wear out when running. Similarly, active nanosystems which incorporate mechanical motion degrade faster when activated. This project will utilize molecular shuttles, nanoscale transport systems powered by the motor protein kinesin, as a model system. Microfabricated guiding structures will be used to exert defined, cyclic loads on the moving shuttles, and optical microscopy will be employed to observe the breaking of the central part of the shuttle. Investigating degradation within these active nanostructures explores new ground, since the molecular shuttle system is too large to be readily described in atomic-level terms of force-activated dissociation of single bonds, but too small to apply macroscopic concepts of wear and fatigue. Thus a mesoscale view of these systems on the nanoscale is required and will be developed through a combination of experiment,simulation, and theory. The result of this research will be an improved understanding of wear and fatigue at the nanoscale. This understanding is on one hand critical for the design of durable devices which can function for their intended lifetime without failure. On the other hand, degradation products may be released from the system, similar to the ?brake dust? created from brake pads in a car. To assess the potential environmental and toxicological impact of active nanosystems it is therefore important to understand how the nanosystem evolves over its lifetime and ultimately fails. While this research is only a first step towards understanding these complex processes, it will ? if successful ? create a template for the evaluation of other active nanosystems and provide a basic scientific framework to understand these degradation processes.