Using Active Materials at Liquid Interfaces to Regulate Bacterial Biofilm Mechanical Properties

在液体界面使用活性材料来调节细菌生物膜的机械性能

• 批准号: 1635245
• 负责人: Gordon Christopher
• 金额: $ 30.05万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635245&HistoricalAwards=false
• 关键词: Using; Active; Materials; Liquid; Interfaces

Bacteria can grow on liquid/air interfaces by attaching to the interface, excreting proteins, and reproducing. This creates a slimy, elastic sheet called a pellicle (a biofilm grown at an air/water interface). Pellicles occur in the lungs of cystic fibrosis patients, where they allow infection to spread, or in oil spill cleanup where they enable oil-degrading bacteria access to crude. To reduce infection, pellicles should be made less stable; to enhance oil cleanup, pellicles should be made more stable. The stability of pellicles depends in part on the bacteria type, which in real-world applications cannot be changed. Therefore, to alter pellicle properties, the local environment needs to be changed to affect bacteria behavior. The PI will alter pellicle properties by adding materials directly to liquid interfaces. For instance, adding soap to an interface weakens biofilms, whereas adding small particles strengthens them. This research will study a range of materials that can modify interfaces and determine how and why the properties of interfaces can be used to control pellicle mechanical strength. An interesting 'super Saturday' science club for elementary students will be supported. 'Science it's a girl thing' for 5th and 11th grade students will also be created. The PI teaches fluids and also serves to promote graduate school to undergraduates. He is part of a formal program in mechanical engineering to enhance diversity and women participation which is low in engineering in particular for mechanical engineering. He will teach a new course and solidly integrates research and educational plans.When surface active materials adsorb to an change the properties of a liquid interface, it is known to affect the viscoelasticity of a pellicle. However, there is little study of this phenomenon and still confusion as to what mechanisms cause observed changes. This research will determine how mechanical and chemical properties of an interface such as viscoelasticity, charge, and wettability affect interfacial viscoelasticity of P. aeruginosa pellicles. This will be done by using specific adsorbed particles, proteins, and surfactants to systematically control interfacial properties. A custom-built rheometer will be employed to characterize interfacial viscoelastic storage and loss moduli and simultaneously monitor bacteria movement within the biofilm. This will allow discernment of the impacts of interface properties on pellicle formation and correlation of biological behavior to interfacial mechanics in a way that has not been previously accomplished. The conclusions drawn about the role of interface properties on pellicle formation will be broadly applicable to all pellicle-forming bacteria due to the focus on mechanistic processes. The resulting data will provide a unique understanding of pellicle formation and a new means to change ultimate mechanical properties of pellicles.

细菌可以通过附着在界面上、分泌蛋白质和繁殖而在液体/空气界面上生长。这就产生了一种叫做薄膜（在空气/水界面生长的生物膜）的粘糊糊的弹性薄片。膜出现在囊性纤维化患者的肺部，在那里它们允许感染传播，或者在漏油清理中，它们使石油降解细菌能够接触原油。为了减少感染，应使薄膜不太稳定;为了增强油清除，应使薄膜更稳定。薄膜的稳定性部分取决于细菌类型，这在现实世界的应用中是无法改变的。因此，为了改变薄膜特性，需要改变局部环境以影响细菌行为。PI将通过直接向液体界面添加材料来改变薄膜特性。例如，在界面上添加肥皂会削弱生物膜，而添加小颗粒会增强它们。这项研究将研究一系列可以修改界面的材料，并确定界面的特性如何以及为什么可以用来控制薄膜的机械强度。 一个有趣的'超级星期六'科学俱乐部的小学生将得到支持。还将为5年级和11年级的学生创建“科学是女孩的事”。PI教授液体，也有助于促进研究生院本科生。他是机械工程的一个正式计划的一部分，以提高多样性和妇女的参与，这是在工程，特别是机械工程低。他将教授一门新的课程，并将研究和教育计划紧密结合起来。当表面活性物质吸附到液体界面的性质改变时，已知会影响薄膜的粘弹性。然而，对这种现象的研究很少，并且仍然不清楚是什么机制导致了观察到的变化。本研究将确定界面的机械和化学性质，如粘弹性，电荷和润湿性如何影响铜绿假单胞菌膜的界面粘弹性。这将通过使用特定的吸附颗粒、蛋白质和表面活性剂来系统地控制界面性质来完成。 一个定制的流变仪将被用来表征界面粘弹性存储和损耗模量，同时监测生物膜内的细菌运动。这将允许以先前未实现的方式辨别界面性质对表膜形成的影响以及生物行为与界面力学的相关性。由于对机械过程的关注，得出的关于界面性质对薄膜形成的作用的结论将广泛适用于所有薄膜形成细菌。由此产生的数据将提供一个独特的理解薄膜的形成和一个新的手段来改变最终的机械性能的薄膜。