Structure and Dynamics of Block Ionomer Complexes

这个项目的主要目标是探索两种类型的分散复合纳米材料，统称为嵌段离聚物复合物或BIC。第一种材料是通过使含有离子和水溶性非离子链段的双重亲水性嵌段共聚物与带相反电荷的聚离子反应而合成的。这些材料在水介质中形成胶束状聚集体，具有聚离子络合物核和亲水性非离子冠。第二种材料是由嵌段共聚物的胶束与带相反电荷的聚离子反应得到的，嵌段共聚物含有离子和水不溶性非离子链段。这种材料包含具有疏水核的胶束，其作为被不溶性聚离子复合物层包围的成核颗粒，以及来自过量存在的聚离子的带电亲水冠。 BIC是近十年来在选择性溶剂中离子型嵌段共聚物和离子型配合物自组装研究的交叉产物。BIC材料在DNA、蛋白质、低分子药物和显像剂等方面有着广泛的应用前景。规则的聚离子络合物的一个基本性质是能够与溶液中存在的其他聚离子组分参与高度合作的聚离子交换反应。初步研究表明，涉及BIC的此类反应也可以进行。虽然这些反应对于BIC的自组装和实际应用具有重要意义，但在这方面还没有系统的研究.本研究将利用荧光技术来确定这些反应的速率和方向，并了解BIC的核壳结构对其动力学性质的贡献。 新型材料的合成和表征，如BIC是通过将具有交联离子核的胶束和具有疏水核和聚离子冠的非离子水溶性冠状胶束与包括DNA和蛋白质在内的各种聚离子反应而获得的。BIC的稳定性、大小、电荷和形态将使用物理化学方法的组合来确定。特别是，该提案将采用原子力显微镜来确定颗粒形貌和小角中子散射来确定颗粒内部结构。BIC的理论分析将与莫斯科国立大学的科学家合作进行。总的来说，该提案将大大推进BIC的实验和理论理解，并开发出可用于生物医学应用的新型BIC材料。 该提案将通过为材料和生物医学科学家之间的合作创造有利环境而产生更广泛的影响，并将有助于内布拉斯加大学及其他地区的学生和科学家的跨学科培训。研究结果将通过药物递送和纳米医学中心的科学会议和研讨会传播，这将促进聚合物纳米材料在药物和基因递送中的应用。研究和教育的整合将受益于PI和Co-PI教授的PolymerTherapeutics课程，该课程结合了最新的科学发现。将通过积极利用互联网，如在线张贴课程和讲座，加强传播。内布拉斯加州的科学和技术理解将通过向广泛的社区团体（如MiniMedical School）进行演讲来增强。这些协同活动将通过提供聚合物材料的应用实例，包括该项目预期的新发现，展示科学发现与社会效益之间的联系。

The major goal of this project is to explore two types of dispersed composite nanomaterialscollectively called the block ionomers complexes or BIC. The first materials are synthesized byreacting dual hydrophilic block copolymers, containing ionic and water soluble nonionicsegments, with oppositely charged polyions. Such materials form micelle-like aggregates withthe polyion complex core and hydrophilic nonionic corona in aqueous media. The secondmaterials are obtained by reacting micelles from block copolymers, containing ionic and waterinsoluble nonionic segments with the polyions of opposite charge. Such materials contain themicelles with hydrophobic cores as nucleating particles surrounded by insoluble polyioncomplex layer and a charged hydrophilic corona from the polyion present in excess. The area of BIC has emerged a decade ago as a result of intersection of the studies on the selfassemblyof polyelectrolyte complexes and ionic block copolymers in selective solvents. Severalpromising applications of BIC materials have been determined, including the delivery of DNA,therapeutic proteins, low molecular mass drugs and imaging agents. One fundamental propertyof regular polyelectrolyte complexes is the ability to participate in highly cooperative polyioninterchange reactions with other polyelectrolyte components present in solution. Initial studiessuggest that such reactions involving BIC can also proceed. Although these reactions are of greatimportance for the self-assembly and practical use of BIC no systematic studies in this area havebeen conducted. This proposal will address this deficiency using fluorescence technique todetermine rates and directions of these reactions and understand the contribution of the core-shellarchitecture of BIC to their dynamic properties. Novel materials will be synthesized and characterized, such as BIC obtained by reactingpolyelectrolyte micelles having cross-linked ionic cores and nonionic water soluble corona ormicelles having hydrophobic cores and polyion corona with various polyions, including DNAand proteins. The stability, size, charge and morphology of the BIC will be determined using acombination of physicochemical methods. In particular, the proposal will employ forcharacterization of BIC the Atomic Force Microscopy to determine the particle topography andSmall Angle Neutron Scattering to determine the particle internal structure. A theoreticalanalysis of the BIC will be carried out in collaboration with scientists at Moscow StateUniversity. Overall the proposal will greatly advance experimental and theoretical understandingof BIC and develop new classes of BIC materials that can be useful in biomedical applications. The proposal will have broader impact by creating a favorable environment for collaborationbetween the material and biomedical scientists and will contribute to interdisciplinary training ofstudents and scientists in the University of Nebraska and beyond. The results of the studies willbe disseminated through scientific meetings and seminars within the Center for Drug Deliveryand Nanomedicine, which will advance applications of polymer nanomaterials in drug and genedelivery. The integration of research and education will benefit from the course on PolymerTherapeutics taught by the PI and Co-PI, which incorporates recent scientific findings. Thedissemination will be enhanced by the active use of Internet, such as online posting of the courseand lectures. The scientific and technological understanding in the State of Nebraska will beenhanced by presentations to broad community groups such as MiniMedical School. Thesesynergistic activities will demonstrate linkage between scientific discoveries and societal benefitby providing the examples of application of polymer materials including the new findingsanticipated from this project.