我們分別運用三種不同游泳模式的單鞭毛溶藻弧菌Vibrio. Alginolyticus，Pusher、Puller和bimodal，觀察細菌在表面的游泳軌跡，以及距離表面20µm以內的細菌分佈。此種細菌的游速可由溶液中的鈉離子濃度調整，利於操控細菌與表面的遠場流體力學交互作用強度。實驗結果顯示細菌在表面游泳時的傾角決定其徘徊於表面機率。而其傾角則取決於近、遠場流體力學交互作用之間的競爭或加成。最後，我們亦能了解野生細菌如何利用游泳模式的轉換在不同的環境下維持其在表面的聚集。 ;Microbial processes including biofilm formation or bio-fouling are ubiquitous and influence human extensively from daily lives to various industrial systems. For decades, researchers studied the processes and strategies of bacteria accumulation on surfaces. Considering the initial stage of biofilm formation, before the cell adhesion, swimming cells were reported swim along the surface for a long time. To describe the phenomenon, models of different perspectives of physics had been established, including far and near field hydrodynamic, steric effects and diffusion. To reach a more complete picture for the cell-surface interaction, we manipulated the swimming characteristic of single polar-flagellated bacteria, Vibrio. Alginolyticus, with mutant strains at different swimming speed. Observing the steady-state bacteria distribution within 20µm from a surface, contributions of each mechanism can be evaluated. Our results show that surface accumulation of microswimmers depends on both swimming speed and swimming characteristic. Accumulation of pusher bacteria is reduced as the speed increases. In contrast, accumulation of puller bacteria increases strongly with the speed. None of a previous model can fully explain our observations. By a closer look, the contribution of each mechanisms are assigned. Finally, we show that a microswimmer in nature can accumulate near a surface by a run and reverse swimming characteristic.
