RUI: Characterizing the birth of a nanoparticle: toward molecular control over nanoparticle synthesis

科学家们正在努力获得对纳米粒子和纳米材料的精确控制。如果这一目标得以实现，社会将获得可定制的纳米材料，这些材料可以按订单生产，用于靶向药物输送、诊断成像和化学分离等应用。然而，尽管科学家们了解了纳米粒子的大小如何增长，但仍然不清楚纳米粒子是如何诞生的。如果不了解纳米颗粒形成的第一步，科学家就无法合理地设计提供定制纳米材料的方案。在这个项目中，旧金山弗朗西斯科州立大学的Krista Vikse教授进行了实验，以揭示纳米粒子种子如何形成的确切细节。与此同时，Vikse教授正在为首次在活跃的化学研究实验室工作的本科生开发增强的教育基础设施。可扫描的快速响应（QR）码正在被纳入物理研究领域。学生可以用手机扫描这些代码，按需链接到相关的虚拟培训材料。通过这种方式，Vikse博士的目标是使所有学生更容易获得STEM研究，减少对所有学生的威胁，特别关注在化学领域代表性不足的学生群体。在NSF化学部大分子，超分子和纳米化学项目的资助下，旧金山弗朗西斯科州立大学的Krista Vikse教授正在阐明金早期还原和成核事件的原子精确机制柠檬酸盐纳米颗粒形成。重点是形成的第一阶段，因为簇从2 - 10个金属原子生长。为此，使用加压样品输注质谱法（PSI-MS）在操作中监测纳米颗粒合成反应混合物。收集所有活性物质的动力学数据。在质谱仪内截获关键中间体，并进行气相离子-分子反应以探测每个中间体的结构和固有反应性。最后，密度泛函理论（DFT）计算阐明详细的结构活性关系的基础上，实验收集的气相数据。对金纳米粒子形成的完整分子理解有助于金属纳米粒子核的合理设计，也为金属簇催化反应领域提供了信息。作为该项目的一个组成部分，Vikse博士和她的学生为第一次在活跃的研究实验室工作的本科生开发和测试教育基础设施。可扫描的快速响应（QR）码被放置在实验室周围的关键位置，让学生直接，按需访问虚拟教学材料使用他们的手机。这使得更容易获得标准化培训，并及时提醒实验室的最佳做法。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Scientists are striving to gain precise control over the creation of nanoparticles and nanomaterials. If this goal is achieved, society will gain access to customizable nanomaterials that can be made-to-order for applications including targeted drug delivery, diagnostic imaging and chemical separations. However, while scientists understand how nanoparticles grow in size, it is still not clear how nanoparticles are born. Without understanding this very first step of nanoparticle formation, scientists cannot rationally design protocols that will deliver custom nanomaterials. In this project, Professor Krista Vikse of San Francisco State University conducts experiments to uncover the exact details of how the seed of a nanoparticle forms. At the same time, Professor Vikse is developing enhanced educational infrastructure for undergraduate students who are working in an active chemical research laboratory for the first time. Scannable Quick Response (QR) codes are being incorporated into the physical research space. Using their cell phones, student can scan these codes to link to relevant virtual training materials on-demand. In this way, Dr. Vikse is aiming to make STEM research more accessible and less intimidating for all students, with a particular focus on groups of students who are underrepresented in the field of chemistry.With funding from the Macromolecular, Supramolecular and Nanochemistry Program of the NSF Chemistry Division, Professor Krista Vikse of San Francisco State University is elucidating the atomically precise mechanism for the early reduction and nucleation events in gold citrate nanoparticle formation. The focus is on the first stage of formation as the clusters grow from 2 - 10 metal atoms. To this end, nanoparticle synthesis reaction mixtures are monitored in operando using pressurized sample infusion mass spectrometry (PSI-MS). Kinetic data are collected for all reactive species. Key intermediates are intercepted within the mass spectrometer and gas-phase ion-molecule reactions are conducted to probe the structure and inherent reactivity of each intermediate. Finally, Density Functional Theory (DFT) calculations elucidate detailed structure-activity relationships based on the experimentally collected gas-phase data. A complete molecular understanding of the formation of gold nanoparticles facilitates the rational design of metallic nanoparticle cores and also informs the field of metal cluster catalyzed reactions. As an integral part of this project, Dr. Vikse and her students develop and test educational infrastructure for undergraduate students who are working in an active research laboratory for the first time. Scannable Quick Response (QR) codes are placed in key locations around the laboratory giving students direct, on-demand access to virtual instructional materials using their cell phones. This allows for increased accessibility to standardized training and timely reminders of best practices in the laboratory. The goal is to improve student confidence in a STEM laboratory setting and ultimately attract students to the STEM profession.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.