生物膜结构对外部流体动力学响应的定量评估对于理解生物膜分离机制至关重要。这项研究使用多维成像和数值模拟方法来阐明希瓦氏菌MR-1的生物膜分离与流体动力学之间的复杂关系。通过将实时共聚焦激光扫描显微镜(CLSM)图像与图像分析工具集成,在层流状态下,在流体动力学处理下以0.42×10-3至3.3×10-3m/s的流速在薄的MR-1生物膜(<10μm)中发生的三维结构变化原位可视化并量化单细胞分辨率。对成像结果的分析表明,生物膜分离的程度和强度具有高度的空间异质性。具有厚且粗糙的生物膜表面或高流速的斑点具有高脱离率,表明局部生物膜形态,包括厚度和粗糙度,和流体动力流动条件共同控制分离速率。数值模拟显示,局部脱离事件与三维水平的水力流动引起的剪切应力之间存在显着相关性。与均匀或薄的生物膜相比,厚的或粗糙的结构可能导致局部生物膜表面在微观尺度上的剪切应力增加2倍。结果提供了对地下环境中生物膜分离过程的定量和微观见解,特别是在动态流动条件下的领域,比如那些在hyporheic地区。生物膜分离与流体动力学和生物膜结构因素之间的关系可以整合到用于描述多孔介质中的微生物生长和运输的反应性运输模型中。重要性分离是决定细菌生物膜结构和功能的重要过程,这对元素的生物地球化学循环具有重要意义,生物膜应用,和临床环境中的感染控制。量化生物膜结构对流体动力学的响应对于理解水生环境中的生物膜分离机制至关重要。在这项工作中,通过使用流动池反应器研究了生物膜结构在不同流体动力学条件下发生的时空变化。我们建立了分离之间的数量关系,生物膜形态,和水动力条件变化引起的剪切应力。这项工作提供了对自然环境中生物膜分离与流体动力学之间复杂关系的定量理解。
Quantitative assessment of the responses of biofilm structure to external hydrodynamics is critical for understanding biofilm
detachment mechanisms. This study used multidimensional imaging and numerical simulation approaches to elucidate the complex relationships between biofilm
detachment and hydrodynamics with Shewanella oneidensis MR-1. By integrating real-time confocal laser scanning microscopy (CLSM) images with image analysis tools, the three-dimensional structural changes occurring in thin MR-1 biofilms (<10 μm) under hydrodynamic treatment at a flow velocity of 0.42 × 10-3 to 3.3 × 10-3 m/s in the laminar flow regime were visualized in situ and quantified with single-cell resolution. Analyses of the imaging results revealed high spatial heterogeneity in the degree and intensity of biofilm detachment. Spots with thick and rough biofilm surfaces or high flow rates had high
detachment rates, indicating that local biofilm morphology, including thickness and roughness, and hydrodynamic flow conditions collectively controlled the detachment rate. Numerical simulations revealed a significant correlation between local
detachment events and the shear stress induced by hydraulic flow at the three-dimensional level. Compared to the even or thin biofilm, a thick or rough structure might induce a 2-fold increase in shear stress over local biofilm surfaces at a microscale dimension. The results provide quantitative and microscopic insights into biofilm detachment processes in subsurface environments, especially in domains under dynamic flow conditions, such as those in hyporheic zones. The relationship between biofilm detachment and hydrodynamics and biofilm structural factors can be integrated into reactive transport models used to describe microbial growth and transport in porous media. IMPORTANCE Detachment is an important process determining the structure and function of bacterial biofilm, which has significant implications for biogeochemical cycling of elements, biofilm application, and infection control in clinical settings. Quantifying the responses of biofilm structure to hydrodynamics is crucial for understanding biofilm detachment mechanisms in aquatic environments. In this work, the spatial and temporal changes occurring in biofilm structures in response to different hydrodynamic conditions were studied by using flow cell reactors. We established the quantitative relationships among
detachment, biofilm morphology, and shear stress induced by changes in hydrodynamic conditions. This work provides a quantitative understanding of the complex relationship between biofilm detachment and hydrodynamics in natural environments.