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液体/空气界面上、分泌蛋白质和繁殖来在液体/空气界面上生长。这会产生一种粘稠的弹性片，称为薄膜（在空气/水界面生长的生物膜）。薄膜出现在囊性纤维化患者的肺部，使感染得以扩散，或者在溢油清理过程中，使石油降解细菌能够接触到原油。为了减少感染，薄膜的稳定性应降低；为了加强油污清理，薄膜应该变得更加稳定。薄膜的稳定性部分取决于细菌类型，这在实际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的行为。 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，而添加小颗粒则会增强生物膜。这项研究将研究一系列可以修改界面的材料，并确定如何以及为何使用界面的特性来控制薄膜的机械强度。 将支持为小学生举办一个有趣的“超级星期六”科学俱乐部。还将为 5 年级和 11 年级的学生创建“科学是女孩的事情”。 PI 教授流体，并负责将研究生院推广至本科生。他是机械工程正式项目的一部分，该项目旨在提高多样性和女性参与度，而该项目在工程领域，尤其是机械工程领域，女性参与度较低。他将教授一门新课程，并将研究和教育计划紧密结合起来。当表面活性材料吸附并改变液体界面的性质时，已知会影响薄膜的粘弹性。然而，对这种现象的研究很少，并且对于什么机制导致观察到的变化仍然存在困惑。这项研究将确定界面的机械和化学特性（例如粘弹性、电荷和润湿性）如何影响铜绿假单胞菌薄膜的界面粘弹性。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特性来实现。 将采用定制的流变仪来表征界面粘弹性存储和损耗模量，并同时监测生物膜内的细菌运动。这将以以前从未实现过的方式辨别界面特性对薄膜形成的影响以及生物行为与界面力学的相关性。由于关注机械过程，关于界面特性对菌膜形成的作用得出的结论将广泛适用于所有形成菌膜的细菌。由此产生的数据将提供对薄膜形成的独特理解以及改变薄膜最终机械性能的新方法。