Elucidation of structure and dynamics of bacterial biofilms by particle tracking

通过粒子追踪阐明细菌生物膜的结构和动力学

• 批准号: 8647359
• 负责人: Alona Birjiniuk
• 金额: $ 4.77万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-05 至 2019-02-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8647359
• 关键词: Affect; Age; Alginates; Antibiotic Resistance; Architecture; Atomic Force Microscopy; Bacteria; Bacterial Infections; Behavior; Blood; Catheters; Cells; Charge; Communication; Communities; Device Removal; Elasticity; Environment; Environmental Protection; Environmental Risk Factor; Excision; Genetic; Goals; Health; Healthcare; Heart Valves; Heterogeneity; Implant; Infection; Knock-out; Lead; Life; Lung; Magnetism; Measurement; Measures; Medical Device; Memory; Methods; Microbial Biofilms; Microfluidic Microchips; Microscopy; Microspheres; Modeling; Motion; Organism; Polymers; Polysaccharides; Property; Prunella vulgaris; Pseudomonas aeruginosa; Relaxation; Role; Sampling; Site; Structure; Surface; System; Techniques; Time; cystic fibrosis patients; extracellular; insight; interest; magnetic beads; mutant; particle; physical property; response; scaffold

DESCRIPTION (provided by applicant): Bacterial biofilms consist of surface adherent bacteria that surround themselves with a polymer matrix that provides environmental protection and antibiotic resistance. Biofilms can grow on most implanted medical devices, on heart valves, and in the lungs of patients with cystic fibrosis, resulting in difficult to treat infections that an become blood-borne and spread throughout the body. Understanding the physical properties of biofilms is therefore of interest as such insight may lead to methods for their disruption and removal. Biofilms have been characterized biochemically, as the general composition of the matrix is known, as are the specific polysaccharides forming the bulk of the matrix for some species. Insight into physical properties of biofilms, such as elasticity and deformability, has been limited to macroscale techniques that assess averaged values. These techniques do not provide details on the spatial gradients of physical properties within a biofilm. Particle trackin is a technique in which multiple microbeads are placed in a material and observed using microscopy, allowing for the determination of physical properties and structure of the material they are embedded in. In this project, particle tracking will be used to assess various living biofilm systems. The overall goal is to gain an understanding of the structure, physical properties, and dynamics of biofilms, and to understand the effects of modulations in age and genetics of the organisms or environmental conditions. The first specific aim is to develop a system for probing the structure and properties of biofilms by using particle tracking to understand a model biofilm system. This will be accomplished by adding microbeads of various sizes and charges to a biofilm either while it is growing or after it has been formed, and then using the motion of the beads to characterize the system. The second specific aim is to actively move beads through a biofilm to understand biofilm dynamics and response to internal perturbation. Magnetic beads will be embedded into a biofilm and moved via magnetic tweezers to deform biofilm and measure how quickly it loses memory of the deformation. In addition, by using fluorescent bacteria it will be possible to analyze if applied internal forces result in bacterial displacement and motion, indicating that it may be possible to activate them within a biofilm. The third and fourth specific aims involve using particle tracking to understand internal perturbation of biofilm structure via the analysis of bacterial strains lacking matrix components and external perturbation of biofilm structure through the addition of known dispersal agents. The technique developed in the first aim will be used to assess the structure of these biofilms as compared to native biofilms in order to understand how to best compromise the integrity of biofilm structure.

描述（由申请人提供）：细菌生物膜由表面附着的细菌组成，这些细菌周围有聚合物基质，可提供环境保护和抗生素抗性。生物膜可以在大多数植入的医疗设备、心脏瓣膜和囊性纤维化患者的肺部生长，导致难以治疗的感染，并通过血液传播并扩散到全身。因此，了解生物膜的物理特性很有意义，因为这种了解可能会带来破坏和去除生物膜的方法。生物膜已被生物化学表征，因为基质的一般组成是已知的，形成某些物种基质主体的特定多糖也是已知的。对生物膜物理特性（例如弹性和可变形性）的深入了解仅限于评估平均值的宏观技术。这些技术没有提供生物膜内物理特性的空间梯度的详细信息。粒子追踪是一种将多个微珠放置在材料中并使用显微镜观察的技术，从而可以确定它们所嵌入的材料的物理性质和结构。在该项目中，粒子追踪将用于评估各种活生物膜系统。总体目标是了解生物膜的结构、物理特性和动力学，并了解生物体年龄和遗传学或环境条件的调节效果。第一个具体目标是开发一种系统，通过使用粒子跟踪来了解模型生物膜系统来探测生物膜的结构和特性。这将通过在生物膜生长时或形成后向生物膜添加不同尺寸和电荷的微珠来实现，然后利用微珠的运动来表征系统。第二个具体目标是主动移动珠子穿过生物膜，以了解生物膜动力学和对内部扰动的响应。磁珠将嵌入生物膜中，并通过磁力镊子移动，使生物膜变形，并测量其失去变形记忆的速度。此外，通过使用荧光细菌，可以分析施加的内力是否导致细菌移位和运动，这表明有可能在生物膜内激活它们。第三和第四个具体目标涉及使用粒子跟踪来了解内部 通过分析缺乏基质成分的细菌菌株来扰动生物膜结构，以及通过添加已知的分散剂来扰动生物膜结构。第一个目标中开发的技术将用于评估这些生物膜的结构与天然生物膜的比较，以便了解如何最好地损害生物膜结构的完整性。