Di Leonardo R, Angelani L, Dell'arciprete D, Ruocco G, Iebba V, Schippa S, Conte M P, Mecarini F, De Angelis F, Di Fabrizio E
Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico-Fisici, c/o Università di Roma Sapienza, I-00185, Rome, Italy.
Proc Natl Acad Sci U S A. 2010 May 25;107(21):9541-5. doi: 10.1073/pnas.0910426107. Epub 2010 May 10.
Self-propelling bacteria are a nanotechnology dream. These unicellular organisms are not just capable of living and reproducing, but they can swim very efficiently, sense the environment, and look for food, all packaged in a body measuring a few microns. Before such perfect machines can be artificially assembled, researchers are beginning to explore new ways to harness bacteria as propelling units for microdevices. Proposed strategies require the careful task of aligning and binding bacterial cells on synthetic surfaces in order to have them work cooperatively. Here we show that asymmetric environments can produce a spontaneous and unidirectional rotation of nanofabricated objects immersed in an active bacterial bath. The propulsion mechanism is provided by the self-assembly of motile Escherichia coli cells along the rotor boundaries. Our results highlight the technological implications of active matter's ability to overcome the restrictions imposed by the second law of thermodynamics on equilibrium passive fluids.
自推进细菌是纳米技术的梦想。这些单细胞生物不仅能够生存和繁殖，而且它们能非常高效地游动、感知环境并寻找食物，所有这些功能都封装在一个几微米大小的身体中。在能够人工组装出如此完美的机器之前，研究人员开始探索利用细菌作为微型设备推进单元的新方法。提出的策略需要将细菌细胞在合成表面上进行排列和结合这项细致的工作，以便它们能够协同工作。在这里，我们展示了不对称环境能够使浸没在活跃细菌浴中的纳米制造物体产生自发且单向的旋转。推进机制是由运动性大肠杆菌细胞沿着转子边界的自组装提供的。我们的结果突出了活性物质克服热力学第二定律对平衡态被动流体所施加限制的能力的技术意义。
