TY - JOUR
T1 - Edge current and pairing order transition in chiral bacterial vortices
AU - Beppu, Kazusa
AU - Izri, Ziane
AU - Sato, Tasuku
AU - Yamanishi, Yoko
AU - Sumino, Yutaka
AU - Maeda, Yusuke T.
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank Hanna Salman for sharing plasmid DNA. Y.T.M. acknowledges support from Grants-in-Aid for Scientific Research on Innovative Areas 16H00805 and 18H05427, Grant-in-Aid for Scientific Research (B) 20H01872, and Grant-in-Aid for Challenging Research (Exploratory) 21K18605 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT); Y.S. acknowledges the support from Grant-in-Aid for Scientific Research on Innovative Areas 16H06478, 19H05403 and 21H00409 from MEXT. K.B. is supported by a fellowship from Japan Society for the Promotion of Science.
Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.
PY - 2021/9/28
Y1 - 2021/9/28
N2 - 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.
AB - 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.
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U2 - 10.1073/PNAS.2107461118
DO - 10.1073/PNAS.2107461118
M3 - Article
C2 - 34561308
AN - SCOPUS:85116965395
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 39
M1 - e2107461118
ER -