Tailorable, responsive, and morphologically-tunable plasmonic chiroptical nanoparticle superstructures

手性纳米材料的研究和控制是一个快速发展的研究领域。手性材料是一种不能与其镜像重叠的物质，就像左手和右手一样。手性纳米材料有潜力用作疾病标志物的传感器，重要工业化学过程的催化剂，以及像照相机一样普通的光学设备和像隐形斗篷一样奇特的光学设备的组件。该研究由美国国家科学基金会固态与材料化学项目和生物材料项目共同支持，重点研究由金纳米颗粒组装的手性纳米材料的开发和进步。匹兹堡大学的研究人员对这些材料的结构和独特的光学特性的优化提出了基本的见解，强调了它们的实际应用前景。这项基础研究涉及到研究生和本科生研究人员的不同群体的参与，他们在科学出版物和演讲中交流他们的发现，以及为公众提供的科学演示。此外，为了增加化学科学的多样性，首席研究员参与有针对性的招聘活动。近年来出现了各种手性纳米粒子超结构，它们表现出独特的等离子体手性。为了推动这一领域的发展并最终实现这些材料的技术前景，研究工作必须集中在以下挑战上：1)有意优化等离子体热学特性；Ii)设计和制备动态和响应等离子体热带材料；iii)发展可持续和可扩展的合成和有效的材料操作手段，以便更广泛地研究和使用它们。这项研究由美国国家科学基金会固态与材料化学项目和生物材料项目共同支持，其中心目标是通过利用分子方法构建纳米粒子超结构来解决这些挑战，这些超结构依赖于肽偶联分子来指导纳米粒子的合成和组装。PI和他的团队：i)阐明肽偶联分子的分子组成和结构如何影响螺旋金纳米颗粒超结构的组装、结构和性能；Ii)开发制造光响应螺旋纳米粒子超结构的新方法，这些超结构具有“开/关”等离子体热学行为，与可逆分子转化相耦合；Iii)建立控制螺旋纳米粒子超结构长度和表面化学的策略；iv)开发新的，可持续的方法来制备螺旋纳米颗粒超结构。这些发现阐明了分子水平上对肽前体的改变如何转化为螺旋纳米粒子超结构的组装、度量和性质的巨大纳米级改变。该研究的变革性影响在于利用分子化学精确控制纳米到微尺度材料结构的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical SummaryThe study and control of chiral nanoscale materials are rapidly growing areas of research. A chiral material is something that cannot be superimposed on its mirror image, like a left and a right hand. Chiral nanomaterials have the potential to serve as sensors for disease markers, as catalysts for important industrial chemical processes, and as components in optical devices as mundane as a camera and as exotic as an invisibility cloak. This research, which is jointly supported by the Solid State and Materials Chemistry program and the Biomaterials program at NSF, focuses on the development and advancement of chiral nanoscale materials assembled from gold nanoparticles. The researchers at the University of Pittsburgh advance fundamental insights into the construction of these materials and optimization of the unique optical properties that underscore their practical promise. This fundamental research involves participation from a diverse group of graduate and undergraduate researchers, who communicate their discoveries in scientific publications and presentations, as well as in science demonstrations for the general public. Additionally, to increase diversity in the chemical sciences the principle investigator engages in targeted recruiting activities.Technical SummaryRecent years have witnessed the emergence of a wide variety of chiral nanoparticle superstructures that exhibit unique plasmonic chiroptical properties. To propel this field forward and to ultimately realize the technological promise of these materials, research efforts must focus on the following challenges: i) deliberate optimization of plasmonic chiroptical properties; ii) design and preparation of dynamic and responsive plasmonic chiroptical materials; and iii) development of sustainable and scalable syntheses and efficient means of material manipulation to allow for their more widespread study and use. The central goal of this research, which is jointly supported by the Solid State and Materials Chemistry program and the Biomaterials program at NSF, is to address these challenges by leveraging molecular methods for constructing nanoparticle superstructures that rely on peptide conjugate molecules to direct nanoparticle synthesis and assembly. The PI and his group: i) elucidate how the molecular composition and structure of peptide conjugate molecules affects the assembly, structure, and properties of helical gold nanoparticle superstructures; ii) develop new approaches for fabricating photo-responsive helical nanoparticle superstructures exhibiting 'on/off' plasmonic chiroptical behavior which is coupled to reversible molecular transformations; iii) establish strategies for controlling the length and surface chemistry of helical nanoparticle superstructures; and iv) develop new, sustainable approaches for preparing helical nanoparticle superstructures. The findings illuminate how molecular-level alterations to peptide precursors translates into dramatic nanoscale alterations to the assembly, metrics, and properties of helical nanoparticle superstructures. The transformational impact of the research lies in the ability to precisely control the structure of nano- to microscale materials using molecular chemistry.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.