A hierarchical bio-mimetic surface engineering approach to prevent biofouling by microbial biofilms

生物污染或有害生物在表面的定植对几种重要的工业相关结构（例如船体、热交换器、传感器和管道）具有有害影响。生物污垢几乎无处不在，控制它仍然是一个极具挑战性的问题。在各种生物污垢相关生物体中，有微生物。微生物具有允许它们以称为生物膜的薄膜的形式“探索”和定殖非生物表面的属性。这些生物膜可导致几种不期望的情况，例如表面降解和能量损失等问题。事实上，微生物对船体的污染可以容易地产生10- 15%数量级的能量损失。目前，需要提供生态友好的解决方案，这一问题引起了新的兴趣，如使用表面形貌的方法，可以防止或延迟生物污垢。在这种情况下，生物启发的设计或仿生设计预计是非常有前途的。拟议的研究计划解决了设计新的抗生物污染表面的挑战，通过使用创新的层次（多尺度）仿生表面形貌。生物材料可以高度组织，在不同的长度尺度，在一个层次的方式与复杂的结构，往往会产生多功能的能力。特别是，该研究计划将寻求采用两种并行的地形尺度：（i）纳米尺度的表面地形，这将干扰分子水平的过程，并使微生物粘附的过程在能量上不利，（ii）较大尺度的地形（长度尺度~ 100 µm），在流体流动的条件下，将导致在表面附近形成二次流。甚至可以在层流条件下形成的二次流可以影响表面附近的质量传递，并且它们将阻止微生物向表面的运输，从而减少微生物进入非生物表面。这些表面特征已经从通常存在于水生生物上的形貌中选择，并且被认为是其防止致病微生物粘附的能力的组成部分。

Biofouling, or the colonization of surfaces by unwanted organisms, has detrimental effects on several important industrially relevant structures, such as ship hulls, heat exchangers, sensors and pipelines. Biofouling is almost ubiquitous and controlling it remains an extremely challenging problem. Amongst the various biofouling relevant organisms are microbes. Microbes have attributes that allow them to 'explore' and colonize abiotic surfaces in the form of thin films called biofilms. These biofilms can result in several undesirable situations, such as surface degradation and energy losses amongst other issues. In fact, fouling of ship hulls by micro-organisms can easily generate energy penalties of the order of 10-15%. Currently, the need to deliver eco-friendly solutions to this problem is causing renewed interest in approaches such as use of surface topographies, which can prevent or delay biofouling. In this context, biologically inspired designs or biomimetic designs are expected to be very promising. The proposed research program addresses the challenge of designing novel bio-fouling resistant surfaces by using an innovative hierarchical (multi-scale) bio-mimetic surface topography. Biological materials can be highly organized, at various length scales, in a hierarchical manner with intricate structures that often give rise to multi-functional capabilities. In particular this research program will seek to employ two concurrent topographic scales: (i) nano-scale surface topographies that will interfere with molecular level processes and make the process of microbial adhesion energetically unfavorable and (ii) larger scale topographies (length scale ~ 100 µm), which under conditions of fluid flow will lead to formation of secondary flows near the surfaces. Secondary flows, which can even form under laminar flow conditions, can affect mass transfer near surfaces, and they would act against the transport of microbes to the surface thereby reducing microbial access to the abiotic surface. These surface features have been chosen from the topographies that are often present on aquatic creatures and are believed to be integral to their ability to prevent adhesion of disease causing microbes.