Surface-enabled propulsion and control of colloidal microwheels.
Surface-enabled propulsion and control of colloidal microwheels.
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DOI：
10.1038/ncomms10225
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发表时间：
2016-01-04
影响因子：
16.6
通讯作者：
Marr DW
中科院分区：
文献类型：
--
作者：
Tasci TO;Herson PS;Neeves KB;Marr DW
微尺度的推进需要独特的策略，例如微生物已经进化为游泳的起伏或旋转的细丝。然而，这些特征可能难以人工复制和控制，从而限制了在实际时间范围内将工程微器件致动和引导到目标位置的能力。游泳的另一种推进策略是滚动。在这里，我们报告说，低强度磁场可以从单个胶体构建块中原位可逆地组装轮形装置，并且还可以以比大多数其他微型推进方案更快的速度驱动、旋转和沿着表面引导它们。通过改变旋转频率和相对于表面的角度，我们证明了微轮可以快速和精确地沿着用户定义的路径。这种能够有针对性地移动的容易改性的胶体装置的原位组装为微尺度应用提供了实用的运输和递送工具，特别是那些复杂或曲折几何形状的应用。 大多数人造微器件都具有仿生特征，但现有系统在速度和方向控制方面还无法与活微生物相匹配。在这里，Tasci等人使用旋转磁场将胶体颗粒可逆地组装成以接近100 μm s−1的速度平移的轮子。
Propulsion at the microscale requires unique strategies such as the undulating or rotating filaments that microorganisms have evolved to swim. These features however can be difficult to artificially replicate and control, limiting the ability to actuate and direct engineered microdevices to targeted locations within practical timeframes. An alternative propulsion strategy to swimming is rolling. Here we report that low-strength magnetic fields can reversibly assemble wheel-shaped devices in situ from individual colloidal building blocks and also drive, rotate and direct them along surfaces at velocities faster than most other microscale propulsion schemes. By varying spin frequency and angle relative to the surface, we demonstrate that microwheels can be directed rapidly and precisely along user-defined paths. Such in situ assembly of readily modified colloidal devices capable of targeted movements provides a practical transport and delivery tool for microscale applications, especially those in complex or tortuous geometries. Most artificial microdevices include biomimetic features, but existing systems do not yet match living microorganisms in speed and direction control. Here, Tasci et al. use a rotating magnetic field to reversibly assemble colloidal particles into wheels that translate at velocities approaching 100 μm s−1.