Bacterial suspensions show turbulence-like spatiotemporal dynamics and vortices moving irregularly inside the suspensions. Understanding these ordered vortices is an ongoing challenge in active matter physics, and their application to the control of autonomous material transport will provide significant development in microfluidics. Despite the extensive studies, one of the key aspects of bacterial propulsion has remained elusive: The motion of bacteria is chiral, i.e., it breaks mirror symmetry. Therefore, the mechanism of control of macroscopic active turbulence by microscopic chirality is still poorly understood. Here, we report the selective stabilization of chiral rotational direction of bacterial vortices in achiral circular microwells sealed by an oil/water interface. The intrinsic chirality of bacterial swimming near the top and bottom interfaces generates chiral collective motions of bacteria at the lateral boundary of the microwell that are opposite in directions. These edge currents grow stronger as bacterial density increases, and, within different top and bottom interfaces, their competition leads to a global rotation of the bacterial suspension in a favored direction, breaking the mirror symmetry of the system. We further demonstrate that chiral edge current favors corotational configurations of interacting vortices, enhancing their ordering. The intrinsic chirality of bacteria is a key feature of the pairing order transition from active turbulence, and the geometric rule of pairing order transition may shed light on the strategy for designing chiral active matter.

细菌悬浮液显示出类似湍流的时空动力学和在悬浮液内不规则移动的涡流。了解这些有序涡旋是活性物质物理学中的一个持续挑战，它们在控制自主物质传输方面的应用将为微流体技术提供重大发展。尽管进行了广泛的研究，但细菌推进的关键方面之一仍然难以捉摸：细菌的运动是手性的，即它打破了镜像对称性。因此，通过微观手性控制宏观主动湍流的机制仍然知之甚少。在这里，我们报告了由油/水界面密封的非手性圆形微孔中细菌涡旋的手性旋转方向的选择性稳定。靠近顶部和底部界面的细菌游动的内在手性在方向相反的微孔横向边界处产生细菌的手性集体运动。这些边缘电流随着细菌密度的增加而变得更强，并且在不同的顶部和底部界面内，它们的竞争导致细菌悬浮液向有利方向全局旋转，从而破坏了系统的镜像对称性。我们进一步证明手性边缘电流有利于相互作用涡旋的共旋转配置，从而增强它们的有序性。细菌的内在手性是活性湍流配对顺序转变的关键特征，配对顺序转变的几何规则可能有助于设计手性活性物质的策略。