Reconfigurable microbots folded from simple colloidal chains
Reconfigurable microbots folded from simple colloidal chains
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DOI：
10.1073/pnas.2007255117
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Tao Yang;Brennan Sprinkle;Yang Guo;Jun Qian;D. Hua;A. Donev;D. Marr;Ning Wu
中科院分区：
文献类型：
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作者：
Tao Yang;Brennan Sprinkle;Yang Guo;Jun Qian;D. Hua;A. Donev;D. Marr;Ning Wu
大多数微尺度游泳者和一些较大的动物利用长丝或细长的身体来推进，因为一维链是最简单的结构，可以弯曲，扭曲，编织或折叠成各种几何或拓扑复杂的形态。受此启发，在这里，我们制造灵活的磁性胶体链，可以使用外加旋进磁场实现形态变化和运动的显着自由度。由于其可重构性，这些系统可以将推进模式从自由游泳切换到表面启用的平移，从而能够在复杂的3D环境中导航，例如模拟动脉，静脉和毛细血管的通道。所展示的形状变化和适应性在自然系统中是普遍存在的，并且是复杂环境中微机器人导航所必需的。为了克服低雷诺数流动的可逆性，已经开发了各种能够快速运输的仿生微型机器人推进方案和装置。然而，这些方法通常针对特定的功能或环境进行了优化，并且不具有许多真实的生物体在复杂的微环境中表现出的灵活性。在这里，受适应性强的微生物的启发，并结合实验和模拟，我们证明了一维胶体链可以折叠成几何复杂的形态，包括螺旋，plectonemes，套索和线圈，并通过多种机制进行翻译，这些机制可以随着施加的磁场而变化。有了多块不对称链，推进模式可以从散装切换到表面启用，模仿微生物的游泳，如鞭毛旋转细菌和尾巴鞭打精子和表面启用运动的伸展和伸展尺蠖和侧旋蛇。我们还证明了可重构性，使导航通过三维和狭窄的通道模拟毛细血管。我们的研究结果表明，基于简单链的柔性微器件可以在不同的磁场下改变形状和运动性，我们预计这种能力在复杂的体内微环境中特别有益。
Significance Most microscale swimmers and some larger animals utilize long filaments or slender bodies for propulsion, since one-dimensional chains are the simplest structure that can be bent, twisted, braided, or folded into a wide range of geometrically or topologically complex morphologies. Inspired by this, here, we fabricate flexible magnetic colloidal chains that can enable significant freedom of morphology change and motion using an applied precessing magnetic field. As a result of their reconfigurability, these systems can switch propulsion mode from free swimming to surface-enabled translation, enabling navigation through complex 3D environments such as channels that mimic arteries, veins, and capillaries. The demonstrated shape change and adaptability are ubiquitous in natural systems and are necessary for microbot navigation in complex environments. To overcome the reversible nature of low-Reynolds-number flow, a variety of biomimetic microrobotic propulsion schemes and devices capable of rapid transport have been developed. However, these approaches have been typically optimized for a specific function or environment and do not have the flexibility that many real organisms exhibit to thrive in complex microenvironments. Here, inspired by adaptable microbes and using a combination of experiment and simulation, we demonstrate that one-dimensional colloidal chains can fold into geometrically complex morphologies, including helices, plectonemes, lassos, and coils, and translate via multiple mechanisms that can be varied with applied magnetic field. With chains of multiblock asymmetry, the propulsion mode can be switched from bulk to surface-enabled, mimicking the swimming of microorganisms such as flagella-rotating bacteria and tail-whipping sperm and the surface-enabled motion of arching and stretching inchworms and sidewinding snakes. We also demonstrate that reconfigurability enables navigation through three-dimensional and narrow channels simulating capillary blood vessels. Our results show that flexible microdevices based on simple chains can transform both shape and motility under varying magnetic fields, a capability we expect will be particularly beneficial in complex in vivo microenvironments.