Oscillatory Diffusion - A New Diffusion Mechanism for Particulates in Porous Media

振荡扩散——多孔介质中颗粒物的新扩散机制

• 批准号: 1926197
• 负责人: Jeffrey Marshall
• 金额: $ 30.94万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1926197&HistoricalAwards=false
• 关键词: Oscillatory; Diffusion; New; Mechanism; Particulates

A bacterial biofilm is formed of bacteria embedded in a network of a secreted material called extracellular polymeric substance (EPS). Bacteria living in biofilms are responsible for many human infectious diseases, including cystic fibrosis, tuberculosis, sinusitis, tooth decay, heart disease, urinary tract infections, and infections from contaminated medical devices and implants. Bacterial biofilms play a central role in food contamination, water purification, greenhouse gas generation, and breakdown of environmental contaminants. Methods for treating biofilms involve nanoparticles or antibiotic liquids that can be encapsulated in small protein capsules called liposomes, which can penetrate into the biofilm and release a chemical onto the bacterial colonies. The research team has found that exposure to ultrasound can enhance the rate of penetration of nanoparticles into a biofilm. This award will support a detailed experimental and theoretical investigation of the underlying hydrodynamic mechanisms responsible for enhanced penetration. The investigators propose that the combination of oscillatory flow produced by the ultrasound plus hindered motion of the particles by the porous medium through which they travel results in a novel type of diffusive transport termed oscillatory diffusion. The award will support experiments to measure the effect of ultrasound on diffusion enhancement of nanoparticles in a hydrogel, which is a model of a biofilm, and to examine the detailed motion of individual particles. A mathematical model will be developed to connect the results of these two experiments. The goal of this project is to improve understanding of the oscillatory diffusion phenomenon, in which acoustic excitation is observed to enhance diffusion of particulates in a porous medium. The target application involves the use of ultrasound to enhance diffusion of nanoparticles and liposomes in a biofilm. The primary mechanism for transport of particles and chemicals in biofilms is diffusion, which regulates supply of minerals and nutrients to bacterial colonies and bacteria gene regulation response via cell population sensing (quorum sensing). The oscillatory diffusion phenomenon was recently discovered by the investigators using moderate-intensity ultrasound to inject liposomes filled with antibiotic chemicals into a biofilm for biofilm mitigation. Ultrasound was also shown to enhance penetration of nanoparticles into an algar hydrogel, which models a biofilm protein matrix. This award will support two experimental components and one modeling component. A nanoparticle bulk diffusion experiment will measure ultrasound-induced nanoparticle diffusion coefficient and acoustic streaming velocity in a hydrogel. An individual particle tracking experiment will track motion of individual particles in a porous bed subject to an oscillating flow field to better understand the phenomenon at the individual particle level. The data from these experimental studies will be used to improve and validate a stochastic model of oscillating diffusion.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

细菌生物膜是由嵌入在称为胞外聚合物（EPS）的分泌物质网络中的细菌形成的。生活在生物膜中的细菌是许多人类感染性疾病的原因，包括囊性纤维化、肺结核、鼻窦炎、蛀牙、心脏病、尿路感染以及受污染的医疗器械和植入物的感染。细菌生物膜在食品污染、水净化、温室气体产生和环境污染物分解中起着核心作用。处理生物膜的方法涉及纳米颗粒或抗生素液体，这些纳米颗粒或抗生素液体可以封装在称为脂质体的小蛋白质胶囊中，脂质体可以渗透到生物膜中并将化学物质释放到细菌菌落上。研究小组发现，暴露在超声波下可以提高纳米颗粒渗透到生物膜中的速度。该奖项将支持一个详细的实验和理论研究的基本水动力机制负责增强渗透。 研究人员提出，由超声波产生的振荡流加上颗粒在多孔介质中的受阻运动，导致了一种新型的扩散运输，称为振荡扩散。该奖项将支持实验，以测量超声波对水凝胶中纳米颗粒扩散增强的影响，水凝胶是生物膜的模型，并检查单个颗粒的详细运动。 将开发一个数学模型来连接这两个实验的结果。这个项目的目标是提高对振荡扩散现象的理解，在这种现象中，观察到声激励可以增强多孔介质中颗粒的扩散。目标应用涉及使用超声来增强纳米颗粒和脂质体在生物膜中的扩散。生物膜中颗粒和化学物质的主要传输机制是扩散，其通过细胞群体感应（群体感应）调节矿物质和营养物质向细菌菌落的供应以及细菌基因调节响应。振荡扩散现象最近被研究人员发现，他们使用中等强度的超声波将充满抗生素化学物质的脂质体注入生物膜中，以减轻生物膜。超声波还显示出增强纳米颗粒渗透到algar水凝胶中，其模拟生物膜蛋白质基质。 该奖项将支持两个实验组件和一个建模组件。纳米颗粒体扩散实验将测量水凝胶中超声诱导的纳米颗粒扩散系数和声学流动速度。单个颗粒跟踪实验将跟踪受到振荡流场的多孔床中单个颗粒的运动，以更好地理解单个颗粒水平的现象。这些实验研究的数据将用于改进和验证振荡扩散的随机模型。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Stochastic model of oscillatory diffusion for colloidal particles in a fixed porous bed

• DOI: 10.1016/j.ces.2021.116993
• 发表时间: 2021-08-14
• 期刊: CHEMICAL ENGINEERING SCIENCE
• 影响因子: 4.7
• 作者: Curran, Kelly;Marshall, Jeffrey S.
• 通讯作者: Marshall, Jeffrey S.

Statistics of particle diffusion subject to oscillatory flow in a porous bed

多孔床中振荡流下颗粒扩散的统计

• DOI: 10.1016/j.ces.2020.116239
• 发表时间: 2021
• 期刊: Chemical Engineering Science
• 影响因子: 4.7
• 作者: Marshall, Jeffrey S.;Arnold, Chloe;Curran, Kelly;Chivers, Thomas
• 通讯作者: Chivers, Thomas

Effect of ultrasound amplitude and frequency on nanoparticle diffusion in an agarose hydrogel

• DOI: 10.1121/10.0012972
• 发表时间: 2022-07-01
• 期刊: JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
• 影响因子: 2.4
• 作者: Karki, Alina;Marshall, Jeffrey S.;Wu, Junru
• 通讯作者: Wu, Junru

Measurement of ultrasound-enhanced diffusion coefficient of nanoparticles in an agarose hydrogel

• DOI: 10.1121/1.5083828
• 发表时间: 2018-12-01
• 期刊: JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
• 影响因子: 2.4
• 作者: Ma, Dong;Marshall, Jeffrey S.;Wu, Junru
• 通讯作者: Wu, Junru