SusChEM: Development of Next-Generation, Ultra-Selective Aquaporin-Based Membranes for Sustainable Water Purification

ElimelechSusChEM：开发下一代超选择性水通道蛋白膜用于可持续水净化从非传统来源（如苦咸水、海水和废水）生产饮用水对于增加全球供水至关重要。反渗透（RO）是海水淡化和废水再利用的主导技术，预计其在全球的使用量将在未来显着增加。此外，一种新兴的膜技术，正渗透（FO），有可能在海水淡化，废水再利用和高盐度盐水处理中发挥重要作用。薄膜复合聚酰胺膜是目前用于这些过程的最先进技术。然而，尽管这些膜的盐截留率相对较高（99%），但它们对各种溶质的选择性不太理想，这导致更高的能耗以及增加的资本和操作成本。增加溶质选择性只能以水渗透性的显著降低为代价来实现，这是由于当前一代聚合物膜的渗透性和选择性之间的固有权衡。迫切需要一种完全不同的膜设计方法，以打破当前膜技术固有的渗透性-选择性权衡。该项目还将通过以下方式促进多样性并加强代表性不足的群体对科学和工程的参与：1）在少数民族服务机构建立生物分子工程研讨会，2）开发远程辅导计划，以促进少数民族服务机构的STEM奖学金，3）积极参加促进科学和工程多样性的会议和研讨会，4）培训和激励本科生，重点关注科学和工程领域代表性不足的群体，5）参与科学推广和对内城低收入少数民族学生的科学指导。 该研究的总体目标是开发一种新型的、超选择性的水通道蛋白膜用于水净化。所提出的新方法利用了水通道蛋白的独特选择性，水通道蛋白是一种仅对水可渗透的完整细胞膜蛋白，以克服当前膜的内在渗透性-选择性权衡。具体目标包括：研究水通道蛋白在包含可聚合脂质或嵌段共聚物的囊泡中的掺入和功能性;发展对破裂技术、表面化学、脂质或嵌段共聚物化学和水通道蛋白浓度对通过囊泡破裂形成栓系支撑双层的影响的基本理解;在化学改性的膜支撑物的顶部上制造稳定和超选择性的基于水通道蛋白的层;以及表征所制造的膜以评估膜水通量和对各种溶质的选择性。为了完成该项目，PI提出了以下任务：1）水通道蛋白的表达和纯化; 2）脂质或三嵌段共聚物的末端官能化以允许双层束缚和聚合; 3）使用停流光散射分析聚合脂质或聚合物囊泡中的水通道蛋白渗透性; 4）评估囊泡破裂技术和模型表面上的双层形成动力学; 5）使用表面改性的商业和手工浇铸的纳滤膜作为双层支持物制造含水通道蛋白的膜; 6）评价制造的膜在反渗透和正渗透中的性能（水通量和溶质截留）;和7）测试膜的机械和化学稳健性。 他们会做到这一点，他们会：（i）研究可聚合脂质中的水通道蛋白功能性，（ii）利用容易发生的化学反应来共价破裂含水通道蛋白的囊泡，（iii）研究共价辅助的含水通道蛋白的囊泡破裂的沉积和破裂动力学，（iv）将含水通道蛋白的双层化学栓系到纳滤膜支持物上，以及，（v）评估中性溶质如氨、尿素和硼的平面水通道蛋白基膜的渗透性。对溶质超选择性的关注也不同于以前的膜开发工作，其主要集中在最大限度地提高水渗透性。

1437630ElimelechSusChEM: Development of Next-Generation, Ultra-selective Aquaporin-based Membranes for Sustainable Water PurificationThe production of drinking water from non-traditional sources, such as brackish water, seawater, and wastewater, is critical to augmenting global water supply. Reverse osmosis (RO) is the dominant technology for desalination and wastewater reuse, and its worldwide usage is expected to significantly increase in the future. In addition, an emerging membrane technology, forward osmosis (FO), has the potential to play an important role in desalination, wastewater reuse, and treatment of high salinity brines. Thin film composite polyamide membranes are currently the state-of-the-art technology for these processes. However, despite the relatively high salt rejection of these membranes (99 %), they have less-than-ideal selectivity to a wide range of solutes, which leads to higher energy consumption and increased capital and operation costs. Increasing solute selectivity can only be achieved at the expense of significant decrease in water permeability due to the intrinsic trade-off between permeability and selectivity of current generation polymeric membranes. A radically different approach for membrane design is critically needed in order to break the inherent permeability-selectivity tradeoff of current membrane technologies. This project will also promote diversity and to enhance the involvement of under-represented groups in science and engineering by: 1) establishing a biomolecular engineering workshop at a minority serving institution, 2) developing a tele-tutoring program to facilitate scholarship in STEM at a minority serving institution, 3) actively participate in conferences and workshops that promote diversity in science and engineering, 4) training and inspiring undergraduate students, focusing on under-represented groups in science and engineering, and, 5) participation in science outreach and science mentoring of inner city, low-income minority students. The overall goal of the proposed research is to develop a novel, ultra-selective aquaporin-based membrane for water purification. The proposed new approach utilizes the uniquely selective nature of aquaporin, an integral cell membrane protein that is permeable only to water, to overcome the intrinsic permeability-selectivity trade-off of current membranes. Specific objectives include: studying aquaporin incorporation and functionality in vesicles comprising polymerizable lipids or block co-polymers; developing a fundamental understanding of the effects of rupture technique, surface chemistry, lipid or block co-polymer chemistry, and aquaporin concentration on the formation of tethered supported bilayers through vesicle rupture; fabricating a stable and ultra-selective aquaporin-based layer on top of a chemically-modified membrane support; and characterizing the fabricated membrane to assess membrane water flux and selectivity for a variety of solutes. To complete the project the PIs propose the following tasks: 1) expression and purification of aquaporin; 2) end-functionalization of lipid or triblock co-polymer to allow for bilayer tethering and polymerization; 3) analysis of aquaporin permeability in polymerized lipid or polymer vesicles using stopped flow light scattering; 4) assessment of vesicle rupture techniques and bilayer formation kinetics on model surfaces; 5) fabrication of aquaporin-containing membranes using surface-modified commercial and hand-cast nanofiltration membranes as a bilayer support; 6) evaluation of the performance (water flux and solute rejection) of fabricated membranes in reverse osmosis and forward osmosis; and, 7) testing the membrane mechanical and chemical robustness. They will accomplish this they will: (i) study aquaporin functionality in polymerizable lipids, (ii) utilize a readily-occurring chemical reaction to covalently rupture aquaporin-containing vesicles, (iii) study the deposition and rupture kinetics of covalent-assisted aquaporin-containing vesicle rupture, (iv) chemically tether an aquaporin-containing bilayer onto a nanofiltration membrane support, and, (v) assess planar aquaporin-based membrane permeability of neutral solutes, such as ammonia, urea, and boron. The focus on solute ultra-selectivity also differs from previous membrane development efforts, which largely focused on maximizing water permeability.