Active materials are capable of converting free energy into mechanical work to produce autonomous motion, and exhibit striking collective dynamics that biology relies on for essential functions. Controlling those dynamics and transport in synthetic systems has been particularly challenging. Here, we introduce the concept of spatially structured activity as a means of controlling and manipulating transport in active nematic liquid crystals consisting of actin filaments and light-sensitive myosin motors. Simulations and experiments are used to demonstrate that topological defects can be generated at will and then constrained to move along specified trajectories by inducing local stresses in an otherwise passive material. These results provide a foundation for the design of autonomous and reconfigurable microfluidic systems where transport is controlled by modulating activity with light.

活性材料能够将自由能转化为机械功以产生自主运动，并表现出生物学赖以实现基本功能的惊人的集体动力学。控制合成系统中的这些动力学和传输尤其具有挑战性。在这里，我们介绍了空间结构化活动的概念，作为控制和操纵由肌动蛋白丝和光敏肌球蛋白马达组成的活性向列液晶中的传输的一种手段。模拟和实验用于证明拓扑缺陷可以随意产生，然后通过在其他被动材料中产生局部应力来限制其沿指定轨迹移动。