Molecular Forces in Microbial Biofilms

这项NSERC发现拨款提案旨在发现稳定各种表面上微生物生物膜形成的分子力的潜在机制。微生物生物膜在加拿大的几个部门（如食品安全、农业、工业和石油管道、船体涂层等）的大多数主要污染问题中起着核心作用，据估计每年要花费数十亿美元。生物膜相关问题日益增多的一个关键原因是我们对细菌附着在各种表面的机制的理解有限，以及对稳定这些生物膜的力量背后的分子理解不足。由于细菌在表面的初始粘附和微菌落形成是成熟生物膜的关键先决条件，因此本研究计划将针对生物膜形成的初始阶段，并将重点放在在生物膜发育的这些关键阶段赋予生物膜稳定性的“分子力”上。特别是，它旨在剖析细菌表面粘附分子与底层底物特性之间的纳米级相互作用，初步解决底物刚度对大肠杆菌生物膜生长的影响。

This NSERC discovery grant proposal seeks to discover mechanisms underlying the molecular forces that stabilize microbial biofilm formation on a wide variety of surfaces. Microbial biofilms play a central role in most major fouling problems in several sectors in Canada (e.g. food safety, agriculture, industrial and oil pipelines, ship hull coatings etc.), and is estimated to cost billions of dollars annually. A key reason behind this growing biofilm-related problems is our limited understanding of the mechanisms by which bacteria adhere to a wide range of surfaces, and the lack of molecular understanding behind the forces responsible for stabilizing these biofilms. As initial adhesion and microcolony formation of bacteria on surfaces are crucial pre-requisites for mature biofilms, this research program will target the initial stages of biofilm formation, and will focus on the “molecular forces” that confer biofilm stability during these critical phases of biofilm development. In particular, it aims to dissect the nanoscopic interplay between bacteria's surface adhesion molecules and the properties of the underlying substrate, initially addressing the influence of substrate stiffness on the growth of E. coli biofilms. While substrate stiffness has long been established to influence mammalian cell signalling and stem cell differentiation, its influence on microbial biofilm growth is rather a recent discovery and is not yet well understood. In order to fill the gap on how substrate stiffness affects the molecular forces that stabilize biofilms, my lab will pioneer a three-way correlated measurements between scanning probe microscopy, optical microscopy, and force spectroscopy, with single-molecule and single-cell resolution. This quantitative and correlated approach to biofilm study will not only provide high-resolution images of the biofilm's complex structures, under physiological conditions, it will also quantify the nanoscale forces that stabilize these structures. The long-term goal is to expand the research to cover other substrate properties, and other biofilm-forming bacteria. This will provide a more general mechanistic insights into how the physico-chemical characteristics of the substrate influence the molecular forces that confer biofilm stability. Results from this research program will not only further our mechanistic understanding of the biofilm's structural stability in adhering to different surfaces, it will also lead to tangible benefits to Canadian industries related to agriculture, energy, environment, and public health, and to the global population, especially with the growing threat of antimicrobial-resistant organisms. Furthermore, with the interdisciplinary nature of the research it will be an excellent training ground for the next generation of Canadian scientists, and will bring Canada at the forefront of quantitative biofilm research.