PITA Fiscal Year 2013 Projects

Enantioselective Separation using Chiral Au Nanoparticles

Lead University: Carnegie Mellon University
PI: Nisha Shukla, ICES
Co-PI: A.J.Gellman, Dept. of Chemical Engineering
PA Industry: Supleco/Sigma-Aldrich

Molecular homochirality is an important characteristic of life on Earth. Although most important biomolecules (DNA, proteins, sugars) have both left- and right-handed structural forms, in living organisms they occur in only one of these two forms. As a result, the physiological impact of chiral bioactive compounds such as fragrances, pharmaceuticals and pesticides depends on their handedness, which must be controlled during production. There have been tremendous advances in understanding chirality on a molecular level; however, implementation and understanding of chirality at the nanoscale is currently emerging in the area of catalysis, sensing, chirooptical devices and enantiomer separations. Recently, the PIs have reported the first observations of enantioselective adsorption of a chiral compound on chiral metal nanoparticles (J. Amer. Chem. Soc. 132(25), 2010, 8575). Enantioselective adsorption is the physical basis for enantioselective separations which are critical to production of most enantiomerically pure compounds such as pharmaceuticals. The previous PITA project allowed systematic study of various chiral ligands for preparation of chiral Au nanoparticles which are capable of enantiospecific adsorption. In addition, systemic study was done to understand the effect of temperature and wavelength on enantiospecific adsorption. Various probe molecules such as 2-butanol, tartaric acid, alanine were also studied. Recenty the PIs have developed a simpler and more robust model than used in their earlier paper for quantifying enantiospecific adsorption equilibrium constants from optical rotation data. In addition, some success was achieved in centrifugal separations with the use of chiral Au nanoparticles to develop a centrifugation based method for enantiospecific purification of chiral compounds. However this part of the project still needs more work. The main aim of this project will be to continue centrifugal separation with the use of chiral Au nanoparticles to develop a centrifugation based method for enantiospecific purification of chiral compounds. The second part of the proposed project will be to use real drugs such ibuprofen and study enantioselective adsoption on chiral Au nanoparticles. This project will also contribute to the training of undergraduate students for research courses 6-200 and CIT honors research (39-500).