Collaborative Research: Elucidating the Mechanisms for Inhibition of Biofouling on Polymeric Membranes Modified with Polyelectrolyte Multilayers and Antimicrobial Nanoparticles

合作研究：阐明聚电解质多层膜和抗菌纳米颗粒改性聚合物膜抑制生物污垢的机制

• 批准号: 1134233
• 负责人: Baoxia Mi
• 金额: $ 17.1万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2011-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1134233&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Mechanisms; Inhibition

PIs: Kai Loon Chen / Baoxia MiProposal Numbers: 1133559 / 1134233Ultrafiltration (UF) membranes are increasingly being used in drinking water treatment and wastewater reuse because of their effectiveness in removing waterborne pathogens and particulate matter. Due to the ubiquity of microorganisms in influent waters, however, UF processes are often hindered by biofouling which reduces clean water production, shortens membrane life, and increases energy demands. Currently, efforts to retard biofouling have centered on using disinfectants, which can damage the membranes and result in the formation of disinfection byproducts. To overcome these limitations, the objective of this research is to investigate the use of polyelectrolyte multilayers (PEMs) to immobilize antimicrobial nanoparticles (NPs) onto the surfaces of polysulfone UF membranes to enhance their resistance to biofouling. Compared to conventional nanocomposite membrane fabrication methods, the use of PEMs would be advantageous because (1) PEMs can increase membrane surface charge and/or hydrophilicity and, thus, reduce bacterial attachment; (2) PEMs ensure that NPs are located on the membrane surface, which will enhance bacterial inactivation; and (3) the application of PEMs is non-destructive and the PEM-NP assembly can be regenerated in situ when the membrane is fouled or the NPs have dissolved. The experiments are designed to test the hypothesis that the resistance of membranes modified by PEMs towards biofouling is controlled by its anti-adhesive and antimicrobial properties. PEM parameters (e.g., constituent polyelectrolytes and NPs and number of bilayers within PEMs) will be systematically varied in order to investigate their influence on the anti-adhesive and antimicrobial properties of the membranes. To probe the membrane?s anti-adhesive properties, the kinetics of bacterial deposition on the membrane during filtration, as well as the adhesive forces between a bacterium and the membrane surface, will be measured. The antimicrobial properties of the membranes will be studied through the enumeration of bacterial colonies on the membrane surface and by using a fluorescent dye technique to detect deposited cells with damaged membranes. The biofouling resistance of membranes modified by PEMs will be evaluated by monitoring the permeate flux decline in long-term filtration experiments with bacteria suspensions. Another component of this research will be to investigate the effects of the above-mentioned PEM parameters on the rate of unintended NP leaching. Finally, this research will examine several physical and chemical methods for the in situ regeneration of PEM-NP assemblies on membrane surfaces and evaluate the performance of the regenerated membranes. This study is novel because it is one of the first to explore the use of PEMs to fabricate biofouling-resistant nanocomposite membranes. Since the incorporation of NPs into PEMs is an emerging field, this research will provide a better understanding of the formation and robustness of PEM-NP assemblies. By systematically varying the constituent polyelectrolytes and NPs of the assemblies, this research will identify the key parameters that govern the membranes? anti-adhesive and antimicrobial properties. The role of the terminating layer in controlling the anti-adhesive properties of a membrane will be examined by replacing the top layers in selected PEM-NP assemblies with layers of PGA-g-PEG, an extremely hydrophilic polyanion. This research will provide insights into the mechanisms of cytotoxicity of surface-immobilized NPs and probe the possible enhancement in membrane antimicrobial activity when antimicrobial chitosan is used as the constituent polycation. This research will create exciting opportunities for the development of the next-generation membrane filtration systems for water purification and potentially transform the way these processes are operated and maintained. Furthermore, this study will provide crucial information allowing for the safe-by-design production of nanocomposite membranes. This work will contribute significantly to the understanding of material design for biofilm prevention, which is also of relevance to the fields of material, chemical, and biomedical engineering. In this study, they will involve undergraduate students in all phases of the research effort. Research results will be disseminated through publications in peer-reviewed journals, student presentations at national scientific meetings, and the organization of a symposium. The broader impact will be further augmented by the involvement of the PI in organizing scientific activities for 5th grade students in a predominantly African American elementary school in inner-city Baltimore. Also, lectures on environmental technologies will be presented at a girls? high school in Washington, DC. The results from this project will also be integrated into a new environmental nanotechnology course at George Washington University.

PI： 陈凯龙/米宝霞提案编号： 1133559 /1134233超滤（UF）膜越来越多地用于饮用水处理和废水再利用，因为它们在去除水性病原体和颗粒物质方面的有效性。 然而，由于微生物在流入沃茨中的普遍存在，UF过程经常受到生物结垢的阻碍，生物结垢减少了清洁水的产生，缩短了膜的寿命，并增加了能量需求。 目前，延缓生物结垢的努力集中在使用消毒剂上，这会损坏膜并导致消毒副产物的形成。 为了克服这些局限性，本研究的目的是调查使用的多层膜（PEM）的抗菌纳米粒子（NP）的聚砜超滤膜的表面上，以提高其抗生物污损。 与传统的纳米复合膜制造方法相比，使用PEM将是有利的，因为（1）PEM可以增加膜表面电荷和/或亲水性，从而减少细菌附着;（2）PEM确保NP位于膜表面上，这将增强细菌灭活;以及（3）PEM的应用是非破坏性的，并且当膜被污染或NP溶解时，PEM-NP组件可以原位再生。实验的目的是测试的假设，即改性的膜对生物污损的阻力是由其抗粘附性和抗菌性能控制。 PEM参数（例如，组成的聚电解质和NP和PEM内的双层数）将系统地变化，以研究它们对膜的抗粘附性和抗微生物性能的影响。 探测细胞膜？的抗粘附性能，过滤过程中细菌在膜上沉积的动力学，以及细菌和膜表面之间的粘附力，将被测量。 将通过膜表面细菌菌落计数和使用荧光染料技术检测膜受损的沉积细胞来研究膜的抗微生物特性。 通过监测细菌悬浮液长期过滤实验中的渗透通量下降来评估由PEM改性的膜的抗生物污染性。 本研究的另一个组成部分将是调查上述PEM参数对非预期NP浸出率的影响。 最后，本研究将探讨几种物理和化学方法，以原位再生的PEM-NP组件的膜表面和评估的再生膜的性能。这项研究是新颖的，因为它是第一个探索使用PEM制造抗生物污染的纳米复合膜。 由于将纳米粒子掺入到质子交换膜中是一个新兴的领域，这项研究将提供一个更好的理解PEM-NP组装体的形成和鲁棒性。 通过系统地改变组成的聚电解质和纳米粒子的组件，这项研究将确定的关键参数，管理膜？抗粘附和抗微生物性能。 终止层在控制膜的抗粘附性能中的作用将通过用PGA-g-PEG（一种极其亲水的聚阴离子）层替换所选PEM-NP组件中的顶层来检查。 本研究将提供深入了解的表面固定的纳米粒子的细胞毒性的机制和探针的抗菌壳聚糖作为组成聚阳离子时，膜的抗菌活性的可能增强。这项研究将为下一代水净化膜过滤系统的开发创造令人兴奋的机会，并可能改变这些过程的操作和维护方式。 此外，这项研究将提供重要的信息，允许安全的设计生产的纳米复合膜。 这项工作将有助于显着的生物膜预防，这也是相关的材料，化学和生物医学工程领域的材料设计的理解。 在这项研究中，他们将涉及本科生在研究工作的所有阶段。 研究成果将通过在同行评审的期刊上发表、学生在国家科学会议上的演讲以及组织专题讨论会等方式传播。 更广泛的影响将进一步扩大参与组织科学活动的五年级学生在一个主要是非洲裔美国人的小学在内城巴尔的摩的PI。 此外，环境技术讲座将在一个女孩？在华盛顿的一所高中 该项目的成果也将纳入乔治华盛顿大学的一门新的环境纳米技术课程。