新たな知見により、マイクロ流体やドラッグデリバリーシステムが進歩する可能性がある。 New insights could advance microfluidics and drug delivery systems
2023-03-08 ノースウェスタン大学
この現象の背後にある物理学を解明したことにより、マイクロ流体アプリケーションや薬物送達システムの発展に貢献する可能性があるとされる。この研究は、3月8日にジャーナルScience Advancesに掲載された。
＜関連情報＞
- https://news.northwestern.edu/stories/2023/03/a-surprising-way-to-trap-a-microparticle/
- https://www.science.org/doi/10.1126/sciadv.ade0320
シンプルなキャッチ：ゆらぎがマイクロローラーの障害物による流体力学的捕捉を可能にする A simple catch: Fluctuations enable hydrodynamic trapping of microrollers by obstacles
Ernest B. van der Wee,Brendan C. Blackwell,Florencio Balboa Usabiaga,Andrey Sokolov,Isaiah T. Katz,Blaise Delmotte,Michelle M. Driscoll
Science Advances Published:8 Mar 2023
DOI:https://doi.org/10.1126/sciadv.ade0320
Abstract
It is known that obstacles can hydrodynamically trap bacteria and synthetic microswimmers in orbits, where the trapping time heavily depends on the swimmer flow field and noise is needed to escape the trap. Here, we use experiments and simulations to investigate the trapping of microrollers by obstacles. Microrollers are rotating particles close to a bottom surface, which have a prescribed propulsion direction imposed by an external rotating magnetic field. The flow field that drives their motion is quite different from previously studied swimmers. We found that the trapping time can be controlled by modifying the obstacle size or the colloid-obstacle repulsive potential. We detail the mechanisms of the trapping and find two remarkable features: The microroller is confined in the wake of the obstacle, and it can only enter the trap with Brownian motion. While noise is usually needed to escape traps in dynamical systems, here, we show that it is the only means to reach the hydrodynamic attractor.
