Light-induced self-assembly of active rectification devices.
Light-induced self-assembly of active rectification devices.
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DOI：
10.1126/sciadv.1501850
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发表时间：
2016-04
期刊：
影响因子：
13.6
通讯作者：
Cates ME
中科院分区：
文献类型：
--
作者：
Stenhammar J;Wittkowski R;Marenduzzo D;Cates ME
响应于光而游动的自推进颗粒可以在非均匀照明下自组装微流体整流装置。自我推进的胶体物体，如能动的细菌或合成的微型游泳者，具有微观上不可逆的个体动力学这是它们与所有生命系统共有的特征。个体游泳者的不连贯行为可以被微流体装置利用（或“纠正”），这些装置可以产生在平衡状态下不可能的系统运动。我们提出了一个计算的概念验证的研究表明，这种主动整流装置可以直接创建从一个非结构化的“原始汤”的光控能动粒子，仅仅通过使用空间调制的照明来控制他们的本地推进速度。除了微观不可逆性和速度调制之外，我们的机制还需要空间对称性破缺，例如V形光图案，以及粒子之间的强相互作用，例如体积排斥，这会导致高密度下的碰撞减速。总之，我们展示了这四个因素如何创造一个新颖的，多体整流机制。我们的工作表明，标准的空间光调制器技术可能允许可编程的，光诱导的自组装的有源整流装置从一个非结构化的粒子浴。
Self-propelled particles that swim in response to light can self-assemble microfluidic rectification devices under nonuniform illumination. Self-propelled colloidal objects, such as motile bacteria or synthetic microswimmers, have microscopically irreversible individual dynamics—a feature they share with all living systems. The incoherent behavior of individual swimmers can be harnessed (or “rectified”) by microfluidic devices that create systematic motions that are impossible in equilibrium. We present a computational proof-of-concept study showing that such active rectification devices could be created directly from an unstructured “primordial soup” of light-controlled motile particles, solely by using spatially modulated illumination to control their local propulsion speed. Alongside both microscopic irreversibility and speed modulation, our mechanism requires spatial symmetry breaking, such as a chevron light pattern, and strong interactions between particles, such as volume exclusion, which cause a collisional slowdown at high density. Together, we show how these four factors create a novel, many-body rectification mechanism. Our work suggests that standard spatial light modulator technology might allow the programmable, light-induced self-assembly of active rectification devices from an unstructured particle bath.