The 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.
Recent 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.
