Building colloidal assemblies via site-specific bonding regions

国家科学基金会-化学运输系统分部颗粒多相过程计划（1415）提案编号：0651611主要研究者：Velegol，Darrell所属机构： Pennsylvania州立大学- University Park提案标题：通过特定位点的键合区域构建胶体组装知识分子MeritColloids和nanocolloids历来用于单一目的，例如聚合物胶体形成膜或TiO 2颗粒散射光。近年来，已经形成了更复杂的颗粒，可以执行受控的药物递送或成像。未来的需求将需要更复杂的多用途组件。这样的组件可能具有诸如补救、传感或受控释放的中心功能，但也可以磁性移动或荧光成像。存在各种方法来组装复杂的颗粒，然而，这些方法还没有提供一个通用的和可扩展的方式来组装各种材料，尺寸和化学functionals.In该提案中，提出了化学和物理的方法来构建复杂的组件，通过放置在单个颗粒上的特定位点的键合区域。在化学上，“颗粒光刻”方法能够将分子或纳米胶体定位在更大的胶体颗粒（尺寸为100 nm）上。在用适当的化学物质对胶体颗粒进行图案化之后，它可以容易地组装成其他颗粒。在物理上，通过在特定位置处稍微压扁颗粒而获得的局部耗尽力使得胶体颗粒能够以容易调节的结合强度结合。我们的愿景是，位点特异性功能化将使胶体设备的制造在许多应用领域。例如，药物递送组件可能由具有用于成像的荧光颗粒和用于靶向的抗原涂覆颗粒的水凝胶颗粒组成;环境修复组件可能由用于污染物吸收的聚合物胶体和用于运输的磁性胶体组成;机器人设备可能由用于检测的传感器颗粒和用于运输的电动纳米马达组成。组装这些和其他器件的一个关键瓶颈是理解组装过程的基本化学和物理。这项工作的智力价值是开发用于组装胶体颗粒的受控的、特定于位点的键合方法。使用分子类比，我们建议使“胶体原子”具有“键价”，使它们能够自组装成“胶体分子”。粒子光刻法允许局部化学功能化，而局部耗尽力允许可旋转和可调谐的键合。开发这些方法需要我们推进基本胶体物理学的知识，特别是在粒子间的力量。更广泛的影响这项工作的更广泛的影响集中在博士生研究与高中生的长期互动的整合。我的博士生学习实验（例如，电泳，FESEM，合成）和建模（例如，布朗动力学，胶体力）技术，我们已经与高度出席中央宾夕法尼亚艺术节，显示有趣的科学超过1000 K-3学生和他们的父母。经过两年的这些短期互动，我们现在假设，与秃鹰地区高中物理学生长达一年的互动将对物理考试成绩和学生进入科学和工程职业产生重大影响。我们将通过合作来检验这一假设。博士生还将他们的研究与REU培训相结合;我实验室过去的六名REU学生与博士生一起在发表的作品中获得了他们的名字。我们的研究将发表在《朗缪尔》、《纳米快报》和《先进材料》等期刊上，使其得到广泛的曝光。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0651611Principal Investigators: Velegol, DarrellAffiliation: Pennsylvania State University - University ParkProposal Title: Building colloidal assemblies via site-specific bonding regionsIntellectual MeritColloids and nanocolloids have historically been used for single purposes, such as polymer colloids forming films or TiO2 particles scattering light. In recent years more complex particles have been formed that can perform controlled drug delivery or imaging. Future demands will require even more complex, multi-purpose assemblies. Such assemblies might have a central function like remediation, sensing, or controlled release, but could also be moved magnetically or imaged fluorescently. Various methods exist for assembling complex particles; however, these methods have not provided a general and scalable way to assemble particles of various materials, sizes, and chemical functionalities.In this proposal both chemical and physical approaches are proposed for building complex assemblies by placement of site-specific bonding regions on individual particles. Chemically, the "particle lithography" method enables the site-specific placement of molecules or nanocolloids onto larger colloidal particles (100 nm in size). After a colloidal particle is patterned with the appropriate chemistry, it can be assembled readily to other particles. Physically, localized depletion forces obtained by slightly flattening particles at specified locations enable colloidal particles to be bonded with an easily-tunable bond strength. The vision is that site-specific functionalization will enable fabrication of colloidal devices in many fields of application. For example, drug delivery assemblies might consist of hydrogel particles with fluorescent particles for imaging and antigen-coated particles for targeting; environmental remediation assemblies might consist of polymer colloids for contaminant absorption and magnetic colloids for transport; robotic devices might consist of sensor particles for detection and electrokinetic nanomotors for transport. A key bottleneck to assembling these and other devices is understanding the fundamental chemistry and physics of the assembly processes.The intellectual merit of this work is the development of controlled, site-specific bonding methods for assembling colloidal particles. To use a molecular analogy, we propose to make "colloidal atoms" having "bonding valences" that enable them to self-assemble into "colloidal molecules". The particle lithography method allows local chemical functionalization, while the localized depletion forces allow rotatable and tunable bonding. Developing these methods requires us to advance the knowledge of fundamental colloidal physics, especially in interparticle forces.Broader ImpactThe broader impacts of this work focus on the integration of PhD student research into longer-term interactions with high school students. My PhD students learn both experimental (e.g., electrophoresis, FESEM, synthesis) and modeling (e.g., Brownian dynamics, colloidal forces) techniques, and we have worked with the highly-attended Central Pennsylvania Festival of the Arts to show interesting science to over 1000 K-3 students and their parents. After two years of these short-term interactions, we now hypothesize that year-long interactions with Physics students at Bald Eagle Area High School will have a significant impact on Physics test scores and students entering science and engineering careers. We will test this hypothesis in a collaborative effort. The PhD students also integrate their research with REU training; the past half dozen REU students in my lab have earned their name on published work alongside the PhD students. Our research will be published in journals like Langmuir, Nano Letters, and Advanced Materials, giving it broad exposure.