Collaborative Research: Design of Templated Ceramic Materials for Separation and Purification of Complex Carbohydrates

复合碳水化合物在生物系统中扮演着许多不可或缺的角色。具有生物活性的多糖（聚糖）与细胞外的蛋白质相互作用，并参与控制细胞间物质的通讯、粘附和运输。人们认识到碳水化合物对许多细胞功能和疾病状态（从唇疱疹到癌症）至关重要，因此有必要分离和纯化特定的碳水化合物以用作药物。然而，合成和纯化特定碳水化合物的技术落后于糖生物学家识别碳水化合物结构和功能的能力。该项目将开发溶胶-凝胶陶瓷材料的微相定向分子印迹技术（MDMI），以设计选择性的、稳定的材料，用于分离和纯化复杂碳水化合物，该材料基于对葡萄糖、氨基葡萄糖和葡萄糖醛酸的聚糖构建块的识别。在MDMI中，印迹位点被锚定在自组装的表面活性剂胶束表面，金属氧化物前体和有机改性硅烷的溶胶-凝胶聚合产生了与印迹位点互补的材料。胶束在加工过程中减少了对溶剂的需求，在干燥过程中稳定了材料，并作为定义良好的孔模板，可以在固化后去除，使印迹位点可访问。假设设计良好的MDMI过程可以产生选择性吸附印迹位点设计的复杂碳水化合物的材料。该合作项目利用化学和材料工程以及合成化学的专业知识，协同关注具有酸性（葡萄糖醛酸）和碱性（氨基葡萄糖）功能分子的MDMI工艺开发的三个关键方面。第一个目标是控制材料前体与印迹分子之间的相互作用，以创造一个完美的结合口袋。第二个目标是基于表面活性剂相行为和相互作用的知识，设计和预测合成高孔隙度、可访问的基质，以支持印迹位点。第三个目标是解决印迹分子本身的合成——具体来说，是有效发挥孔隙模板和分子印迹位点双重作用的分子。这些目标中的每一个都是从易于获得的实验系统开始的，并且随着达到印迹复杂多糖的最终目标的里程碑而变得复杂。通过多孔模板/分子印迹分子的双重用途对陶瓷进行分子印迹，对开发用于分离功能性多糖的高性能吸附剂具有潜在的变革意义。通过结合溶胶-凝胶材料的合成通用性和分子印迹的选择性，本研究将通过印迹和碳水化合物结合机制的知识建立定制陶瓷的方法。在合成的溶胶-凝胶基质中，聚糖和蛋白质之间的高度选择性锁和钥匙相互作用将被用于分离生物学相关的多糖。该项目的成功将增强我们对碳水化合物在生物功能中的作用的认识，扩大这些分子的商业潜力，并培养能够领导复杂碳水化合物分离领域的人才。糖印迹材料MDMI的成功开发将促进合成糖的纯化、有价值农产品的回收和基于植物的药物发现，并最终为碳水化合物传感器和模拟酶催化剂提供改进的平台。拟议的项目将突出生物分离的关键作用，并开发推广材料、研究经验和课程，以扩大肯塔基大学新的本科生物制药工程证书课程对研究生水平教育的影响。

Complex carbohydrates play many integral roles in biological systems. Biologically active polysaccharides (glycans) interact with proteins on the outside of cells, and are involved in controlling communication, adhesion, and transport of material between cells. The need to isolate and purify specific carbohydrates for use as drugs has emerged from the realization that carbohydrates are central to many cell functions and disease states, ranging from cold sores to cancer. However, the technology to synthesize and purify specific carbohydrates is falling behind the ability of glycobiologists to identify the structure and function of carbohydrates. This project will develop microphase-directed molecular imprinting (MDMI) of sol-gel ceramic materials to design selective, stable materials for the separation and purification of complex carbohydrates based on recognition of the glycan building blocks of glucose, glucosamine, and glucuronic acid. In MDMI, imprinting sites are anchored on the surface of self-assembled surfactant micelles, and sol-gel polymerization of metal oxide precursors and organically modified silanes create a material complementary to the imprinting sites. The micelles reduce the need for solvents during processing, stabilize the material during drying, and serve as well-defined pore templates that can be removed after curing to make the imprinted sites accessible. A well designed MDMI process is hypothesized to produce materials that selectively adsorb the complex carbohydrate for which the imprinting sites were designed. This collaborative project employs the expertise of chemical and materials engineering and synthetic chemistry to focus synergistically on three critical aspects of the development of the MDMI process for molecules with acidic (glucuronic acid) and basic (glucosamine) functionality. The first aim addresses control of the interactions between material precursors and imprinting molecule to create a perfect binding pocket. The second aim addresses the design and predictive synthesis of a high-porosity, accessible matrix to support the imprinted sites based on knowledge of surfactant phase behavior and interactions. The third aim addresses the synthesis of the imprinting molecules themselves--specifically, molecules that effectively play dual roles as pore templates and molecular imprinting sites. Each one of these aims begins from easily accessible experimental systems and builds in complexity as milestones are reached toward the ultimate goal of imprinting complex polysaccharides. The molecular imprinting of ceramics through dual-use pore templating/molecular imprinting molecules is potentially transformative to the development of high performance adsorbents for the separation of functional polysaccharides. By combining the synthetic versatility of sol-gel materials and the selectivity of molecular imprinting, the proposed work will establish approaches to customizing ceramics through the knowledge of imprinting and carbohydrate binding mechanisms. Mimicry of the highly selective lock and key interaction between glycans and proteins within synthetic sol-gel matrices will be developed for the isolation of biologically relevant polysaccharides. Success of this project will enhance our knowledge of the role of carbohydrates in biological function, expand the commercial potential of these molecules, and develop personnel capable of leading the field of complex carbohydrate separations. The successful development of MDMI for saccharide-imprinted materials will advance synthetic saccharide purification, and also the recovery of valuable agricultural products and plant-based drug discovery, and eventually provide for improved platforms for carbohydrate sensors and enzyme-mimicking catalysts. The proposed project will highlight the critical role of bioseparations and develop outreach materials, research experiences, and curriculum that expand the impact of a new undergraduate Biopharmaceutical Engineering Certificate program at the University of Kentucky to graduate level education.