Hogan Kayla, Paul Sai, Lin Guanyou, Fuerte-Stone Jay, Sokurenko Evgeni V, Thomas Wendy E
Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
Pathogens. 2023 Jul 15;12(7):941. doi: 10.3390/pathogens12070941.
Bacterial adhesion is the first step in the formation of surface biofilms. The number of bacteria that bind to a surface from the solution depends on how many bacteria can reach the surface (bacterial transport) and the strength of interactions between bacterial adhesins and surface receptors (adhesivity). By using microfluidic channels and video microscopy as well as computational simulations, we investigated how the interplay between bacterial transport and adhesivity affects the number of the common human pathogen that bind to heterogeneous surfaces with different receptor densities. We determined that gravitational sedimentation causes bacteria to concentrate at the lower surface over time as fluid moves over a non-adhesive region, so bacteria preferentially adhere to adhesive regions on the lower, inflow-proximal areas that are downstream of non-adhesive regions within the entered compartments. Also, initial bacterial attachment to an adhesive region of a heterogeneous lower surface may be inhibited by shear due to mass transport effects alone rather than shear forces per se, because higher shear washes out the sedimented bacteria. We also provide a conceptual framework and theory that predict the impact of sedimentation on adhesion between and within adhesive regions in flow, where bacteria would likely bind both in vitro and in vivo, and how to normalize the bacterial binding level under experimental set-ups based on the flow compartment configuration.
细菌黏附是表面生物膜形成的第一步。从溶液中黏附到表面的细菌数量取决于有多少细菌能够到达表面（细菌运输）以及细菌黏附素与表面受体之间相互作用的强度（黏附性）。通过使用微流体通道、视频显微镜以及计算模拟，我们研究了细菌运输与黏附性之间的相互作用如何影响与具有不同受体密度的异质表面结合的常见人类病原体的数量。我们确定，随着流体在非黏附区域流动，重力沉降会使细菌随着时间的推移集中在下表面，因此细菌优先黏附在进入隔室内非黏附区域下游较低的、靠近流入端区域的黏附区域。此外，仅由于质量传输效应而非剪切力本身，初始细菌附着到异质下表面的黏附区域可能会受到剪切的抑制，因为较高的剪切力会冲走沉降的细菌。我们还提供了一个概念框架和理论，预测沉降对流动中黏附区域之间以及黏附区域内黏附的影响，在这种情况下细菌可能在体外和体内都发生黏附，以及如何根据流动隔室配置在实验设置下对细菌结合水平进行归一化。
