Wang Xiaoyu, Sprinkle Brennan, Bisoyi Hari Krishna, Yang Tao, Chen Lixiang, Huang Shuai, Li Quan
Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China.
Department of Mathematics, Colorado School of Mines, Golden, CO 80401.
Proc Natl Acad Sci U S A. 2023 Sep 12;120(37):e2304685120. doi: 10.1073/pnas.2304685120. Epub 2023 Sep 5.
Microrobot swarms have seen increased interest in recent years due to their potentials for in vivo delivery and imaging with cooperative propulsion modes and enhanced imaging signals. Yet most swarms developed so far are limited to dense particle aggregates, far simpler than complicated three-dimensional assemblies of anisotropic particles. Here, we show via assembly path design that complex hollow tubular structures can be assembled from simple isotropic colloidal spheres and those complicated, metastable, microtubes can be formed from simple, energetically favorable colloidal membranes. The assembled microtubes can remain intact and roll under a precessing magnetic field, with propulsion directions and velocities precisely controlled by field components. The hollow spaces inside enable these tubular microrobots to grab, transport, and release cargos on command. We also demonstrate unique compressing and uncompressing capabilities with our tubular microrobots, making them effective microtweezers. Our work shows that complicated microrobots can be transformed from simple assemblies, providing an insight on building micromachines.
近年来，微型机器人集群因其在体内递送和成像方面的潜力，以及协同推进模式和增强的成像信号而受到越来越多的关注。然而，到目前为止开发的大多数集群仅限于密集的粒子聚集体，远比各向异性粒子的复杂三维组装简单得多。在这里，我们通过组装路径设计表明，复杂的中空管状结构可以由简单的各向同性胶体球组装而成，而那些复杂的、亚稳态的微管可以由简单的、能量有利的胶体膜形成。组装好的微管可以保持完整，并在进动磁场下滚动，推进方向和速度由磁场分量精确控制。内部的中空空间使这些管状微型机器人能够根据指令抓取、运输和释放货物。我们还展示了管状微型机器人独特的压缩和解压能力，使其成为有效的微型镊子。我们的工作表明，复杂的微型机器人可以由简单的组件转化而来，为构建微机器提供了思路。
