Microscopic artificial swimmers
Microscopic artificial swimmers
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DOI：
10.1038/nature04090
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发表时间：
2005-10-06
期刊：
影响因子：
64.8
通讯作者：
Bibette, J
中科院分区：
文献类型：
--
作者：
Dreyfus, R;Baudry, J;Bibette, J
微生物，如细菌和许多真核细胞，用被称为鞭毛的毛发状结构推动自己，鞭毛可以表现出各种结构和运动模式（1）。例如，细菌鞭毛呈螺旋状（2），其基部由可逆旋转发动机（3）驱动，该发动机旋转附着的鞭毛以产生类似于开瓶器的运动。相比之下，真核细胞使用类似于弹性杆的鞭毛（4），并表现出跳动运动：内部产生的应力引起一系列弯曲，并向尖端传播（5-7）。与自然界中遇到的各种游泳策略相反，人造微米尺寸结构的受控游泳运动尚未实现。在这里，我们表明，由DNA连接并附着在红细胞上的胶体磁性颗粒的线性链可以充当柔性人工鞭毛。灯丝与外部均匀磁场对齐，并且很容易通过振荡横向场来驱动。我们发现，驱动诱导的跳动模式，推动的结构，并可以调整外部字段来控制运动的速度和方向。
Microorganisms such as bacteria and many eukaryotic cells propel themselves with hair-like structures known as flagella, which can exhibit a variety of structures and movement patterns(1). For example, bacterial flagella are helically shaped(2) and driven at their bases by a reversible rotary engine(3), which rotates the attached flagellum to give a motion similar to that of a corkscrew. In contrast, eukaryotic cells use flagella that resemble elastic rods(4) and exhibit a beating motion: internally generated stresses give rise to a series of bends that propagate towards the tip(5-7). In contrast to this variety of swimming strategies encountered in nature, a controlled swimming motion of artificial micrometre-sized structures has not yet been realized. Here we show that a linear chain of colloidal magnetic particles linked by DNA and attached to a red blood cell can act as a flexible artificial flagellum. The filament aligns with an external uniformmagnetic field and is readily actuated by oscillating a transverse field. We find that the actuation induces a beating pattern that propels the structure, and that the external fields can be adjusted to control the velocity and the direction of motion.