NSF Award
2404199
With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Shumaker-Parry's group at the University of Utah is studying the optical properties of metal nanostructures to improve the detection of chiral molecules. Chirality is a foundational property of molecules defined by the three-dimensional arrangement of connected atoms and the inability of a molecule to be superimposed on its mirror image. Chirality is of critical importance in determining the behavior of molecules, especially in medicine. For example, the chirality of a molecule developed as a therapeutic could determine if the drug is effective, inactive, or toxic. Vibrational Circular Dichroism (VCD) spectroscopy is used to detect and identify chiral molecules. However, the method requires large quantities of material, excluding the ability for trace analysis and detection of impurities. The Shumaker-Parry research group is studying incorporation of metal nanostructures with special optical behavior for VCD to enhance detection of chiral molecules. The development of enhanced VCD analysis through these studies could make plasmon-enhanced VCD a key analytical method for the pharmaceutical industry to improve both efficacy and safety of new drugs. The research incorporates chemistry, physics, and aspects of engineering, providing broad training for graduate and undergraduate students. The interdisciplinary approaches form a foundation for education and outreach activities.<br/><br/><br/>Analytical strategies for detection of chiral molecules are limited due to the challenge of dealing with enantiomers that have the same chemical formula and differ only in the three-dimensional spatial arrangement of atoms. The goal of the proposed research is to investigate plasmonic nanostructures with tunable infrared (IR) plasmons and orientation-dependent chiroptical activity for plasmon-enhanced vibrational circular dichroism (PE-VCD) spectroscopy. VCD combines IR spectroscopy and circular dichroism (CD) to provide information about chemical groups and local environment for chiral-based structural analysis of small molecules, biological molecules, and higher order assemblies. The research builds on observations of the coupling of chiral and achiral molecules with plasmonic nanostructures impacting both molecular VCD spectral signatures and IR CD of the nanostructures. The objectives of the proposed research are to 1) improve the capabilities of the VCD instrument for solid substrate measurements, 2) study the coupling of chiral molecules with chiroptically-active plasmonic nanostructures, and 3) investigate the influence of IR CD activity of plasmonic structures on achiral molecules. Through these studies, the mechanisms for the molecule-plasmon coupling observed in the IR CD and VCD spectra of the nanostructures and molecules will be explored. The findings from these investigations will establish a foundation for PE-VCD for the analysis of chiral molecules. Graduate and undergraduate students will be broadly trained through the interdisciplinary research incorporating nanofabrication, materials characterization, optical studies, and simulations. The interdisciplinary nature of nanoscience also provides the foundation for education and outreach activities.<br/><br/>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.
