Collaborative Research: Cohesive Strength and Detachment of Bacterial Biofilms

Holzalski，Raymond，PI明尼苏达大学双城分校CBET-0728550 Stewart，菲利普，PI蒙大拿州立大学CBET-0728621合作研究：细菌生物膜的内聚强度和分离本项目的目标是在对生物膜细胞外基质内聚机制的进一步理解的基础上，开发有效的控制和去除微生物生物膜的策略。生物膜是附着在湿润表面上的细菌或真菌细胞的密集聚集体。这些细胞通过细胞自身分泌的高度水合的生物聚合物的混合物保持在一起。生物膜是配水系统、工业设备中令人烦恼的污垢以及医学和牙科中的持续感染的原因。该项目将控制不需要的生物膜的方法从用抗菌剂杀死微生物转变为削弱生物膜结构并促进分离。该策略的关键是直接测量生物膜的内聚强度并将强度与分离相关联。该项目的具体目标是：（1）调查生物膜内聚强度和分离的机制，（2）评估环境条件对强度和分离的影响，（3）测量潜在干扰剂化合物对强度和分离的影响。这些目标将在实验中解决的单一物种和混合物种的生物膜的组合。核心技术是微悬臂梁方法，用于拉动一块生物膜并量化其机械性能。其他方法包括通过光学显微镜和共聚焦扫描激光显微镜对连续流动条件下玻璃毛细反应器中的生物膜结构进行延时成像，以及对旋转圆盘反应器中生物膜脱落的测量。该研究将通过开发控制生物污染的方法来影响工程，例如在管道中，减少生物膜积累可以提高供水安全并减少能量损失。在公共卫生方面，这项研究将提供对抗细菌感染的替代方法，例如在医疗植入设备或囊性纤维化患者肺部遇到的细菌感染，以减少对冗余手术的需求并改善/延长寿命。来自这两个机构的研究生和本科生将参加研究。这两组学生将有机会与行业互动，并在该中心主办的一年两次的会议上向生物膜工程中心的行业同仁介绍。

Holzalski, Raymond, PIUniversity of Minnesota-Twin CitiesCBET-0728550Stewart, Phillip, PIMontana State UniversityCBET-0728621Collaborative Research: Cohesive Strength and Detachment of Bacterial BiofilmsThe goal of this project is to develop effective strategies for controlling and removing microbial biofilms based on an improved understanding of the mechanisms of cohesion of the biofilm extracellular matrix. Biofilms are dense agglomerations of bacterial or fungal cells that attach to wetted surfaces. These cells are held together by a mixture of highly hydrated biopolymers that the cells themselves secrete. Biofilms are responsible for troublesome fouling in water distribution systems, industrial equipment and persistent infections in medicine and dentistry. This project shifts the approach to controlling unwanted biofilms from killing microorganisms with antimicrobial agents to weakening the biofilm structure and promoting detachment. A key to this strategy is to directly measure the cohesive strength of biofilms and relate strength to detachment. Specific objectives of this project are to: (1) investigate mechanisms responsible for biofilm cohesive strength and detachment, (2) evaluate the effect of environmental conditions on strength and detachment, and (3) measure the effects of potential disruptor compounds on strength and detachment. The objectives will be addressed experimentally in a combination of single-species and mixed-species biofilms. A central technique is a micro-cantilever method for pulling on a piece of biofilm and quantifying its mechanical properties. Other methods include time-lapse imaging of biofilm structures in glass capillary reactors under continuous-flow conditions by light microscopy and confocal scanning laser microscopy and measurements of biofilm detachment in rotating disk reactors.The research will impact engineering through the development of methods to control biofouling, such as in pipelines, where decreased biofilm accumulation could improve the safety of water supplies and reduce energy losses. In terms of public health, this research will provide alternative methods for fighting bacterial infections, such as those encountered on medical implant devices or in the lungs of cystic fibrosis patients, to reduce the need for redundant surgeries and improve/extend life. Graduate and undergraduate students from both institutions will participate in the research. Both groups of students will be afforded opportunities to interact with industry and to present to industrial associates of the Center for Biofilm Engineering at the biannual conference hosted by the center.