IRFP: Determination of Solvent Effects and Interactions of Silica-Polypeptide Colloidal Particles by Small-Angle Neutron Scattering

国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该项目的奖项提供了联合研究的机会，并提供了使用国外独特或互补的设施、专业知识和实验条件的机会。这一奖项将支持由Javoris V.Hollingsworth博士与中国科学院化学研究所教授中国合作提供的为期24个月的研究奖学金。本研究项目的目的是研究二氧化硅-多肽胶体颗粒的溶剂效应、结构变化以及由此产生的壳层互穿。这些颗粒由硅核组成，它可能具有也可能不具有超顺磁性包裹体(Co或Fe3O4)。壳层由共价键合到核心的多肽组成。根据附着的聚合物的性质，颗粒可以在水或有机溶剂中表现出溶解性。此外，多肽螺旋-螺旋转变是改变表面构型和颗粒相互作用的有用特征。这些粒子在响应材料、手性分离、催化、胶体结晶、仿生膜载体和药物输送系统等方面具有潜在的应用前景。关于粒子的许多特征已经被描述--例如，它们可以形成胶体晶体，但人们对粒子在外加电场下的动态响应知之甚少。总体目标是了解这些特性，同时这些发现将对用于设计新型响应性材料和设备的方法产生积极影响。小角中子散射(SANS)研究是在中国原子能研究所中子散射实验室进行的。这个SANS装置是世界上最新建造的中子系统之一。在获得了由主体组开发的类似颗粒的经验后，总体目标是使用SANS结合动态光散射(DLS)研究颗粒在外加磁场下聚集时的壳层结构特性。SANS和DLS的结合对于这项研究是理想的，因为这两种技术都允许实时监测结构变化。粒子之间的相互作用可以通过使用氢化和氢化多肽共价连接到二氧化硅核上的SANS来检测。除了通常的国际伙伴关系、出版物和演示文稿的发展外，PI还将使他获得的技能适应美国的中子源。这一持续的研究努力将有助于材料科学的进步，因为它提供了对多功能核壳胶体系统的微观结构和响应特性的洞察。

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Javoris V. Hollingsworth to work with Prof. Charles Han at the Institute of Chemistry, Chinese Academy of Science in Beijing, China. The aim of this research project is to investigate the solvent effects, structural variations and the resulting shell interpenetration of silica-polypeptide colloidal particles. These particles are composed of a silica core, which may or may not possess a superparamagnetic inclusion (Co or Fe3O4). The shell consists of polypeptides covalently bonded to the core. Depending on the properties of the attached polymers, the particles can exhibit solubility in water or organic solvents. Also, the polypeptide coil-helix transition is a useful feature for modifying the surface configuration and particle interactions. These particles are candidates for several potential applications such as responsive materials, chiral separations, catalysis, colloidal crystallization, biomimetic membrane supports and drug delivery systems. A number of features about the particles have been described-for example, they can form colloidal crystals'but very little is known about the dynamic response of the particles under applied fields. An overall goal is to understand these properties and concurrently the findings will have a positive impact on the approach used to design novel responsive materials and devices. Small angle neutron scattering (SANS) studies are performed at the Neutron Scattering Laboratory, China Institute of Atomic Energy. This SANS device is one of the most recently built neutron systems in the world. After gaining experience with similar particles of interest developed by the host group, the general objective is to investigate shell structural properties as the particles are brought together under applied magnetic fields using SANS, coupled with dynamic light scattering (DLS). The combination of SANS and DLS is ideal for this study because both techniques permit real-time monitoring of structure variations. Particle interactions are detectable by SANS using deuterated and hydrogenous polypeptides covalently attached to silica cores. In addition to the usual development of international partnerships, publications and presentations, the PI will adapt his acquired skills to U.S. neutron sources. This continued research endeavor will contribute to the advancement of materials science by providing insight on microstructural and responsive properties of versatile core-shell colloidal systems.