Senevirathne S W M A Ishantha, Mathew Asha, Toh Yi-Chin, Yarlagadda Prasad K D V
Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD4000, Australia.
School of Mechanical, Medical, and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD4000, Australia.
ACS Omega. 2022 Nov 4;7(45):41711-41722. doi: 10.1021/acsomega.2c05828. eCollection 2022 Nov 15.
Bacterial colonization on solid surfaces creates enormous problems across various industries causing billions of dollars' worth of economic damages and costing human lives. Biomimicking nanostructured surfaces have demonstrated a promising future in mitigating bacterial colonization and related issues. The importance of this non-chemical method has been elevated due to bacterial evolvement into antibiotic and antiseptic-resistant strains. However, bacterial attachment and viability on nanostructured surfaces under fluid flow conditions has not been investigated thoroughly. In this study, attachment and viability of (. ) and (. ) on a model nanostructured surface were studied under fluid flow conditions. A wide range of flow rates resulting in a broad spectrum of fluid wall shear stress on a nanostructured surface representing various application conditions were experimentally investigated. The bacterial suspension was pumped through a custom-designed microfluidic device (MFD) that contains a sterile Ti-6Al-4V substrate. The surface of the titanium substrate was modified using a hydrothermal synthesis process to fabricate the nanowire structure on the surface. The results of the current study show that the fluid flow significantly reduces bacterial adhesion onto nanostructured surfaces and significantly reduces the viability of adherent cells. Interestingly, the bactericidal efficacy of the nanostructured surface was increased under the flow by ∼1.5-fold against and ∼3-fold against under static conditions. The bactericidal efficacy had no dependency on the fluid wall shear stress level. However, trends in the dead-cell count with the fluid wall shear were slightly different between the two species. These findings will be highly useful in developing and optimizing nanostructures in the laboratory as well as translating them into successful industrial applications. These findings may be used to develop antibacterial surfaces on biomedical equipment such as catheters and vascular stents or industrial applications such as ship hulls and pipelines where bacterial colonization is a great challenge.
固体表面的细菌定殖在各个行业引发了巨大问题，造成了价值数十亿美元的经济损失并危及人类生命。仿生纳米结构表面在减轻细菌定殖及相关问题方面展现出了广阔前景。由于细菌进化出对抗生素和防腐剂的抗性菌株，这种非化学方法的重要性日益凸显。然而，在流体流动条件下纳米结构表面上细菌的附着和生存能力尚未得到充分研究。在本研究中，研究了在流体流动条件下（.）和（.）在模型纳米结构表面上的附着和生存能力。实验研究了一系列流速，这些流速在代表各种应用条件的纳米结构表面上产生了广泛的流体壁面剪应力。将细菌悬浮液泵入一个定制设计的微流控装置（MFD）中，该装置包含一个无菌的Ti-6Al-4V基板。通过水热合成工艺对钛基板表面进行改性，以在表面制备纳米线结构。当前研究结果表明，流体流动显著降低了细菌在纳米结构表面的附着力，并显著降低了附着细胞的生存能力。有趣的是，在流动条件下，纳米结构表面的杀菌效果在静态条件下对（.）提高了约1.5倍，对（.）提高了约3倍。杀菌效果与流体壁面剪应力水平无关。然而，两种细菌的死菌数随流体壁面剪应力的变化趋势略有不同。这些发现对于在实验室中开发和优化纳米结构以及将其转化为成功的工业应用将非常有用。这些发现可用于在诸如导管和血管支架等生物医学设备上开发抗菌表面，或用于诸如船体和管道等细菌定殖是巨大挑战的工业应用中。
