Surface and confinement effects on lipid films by NMR

• Applicant: Professor Dr. Dan Eugen Demco
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2004 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5426202

• Final Report Year: 2008

Final Report Abstract

The main goal of this project is to characterize qualitatively and quantitatively the molecular order and dynamics of lipid films induced by the solid supports and the geometrical confinement. The understanding of these effects is important due to their potential applications in biosensing and bioseparations. Various NMR methods working under static and magic angle sample spinning conditions were used to obtain information about the H and C- H residual dipolar couplings that can be correlated with dynamic order parameters and heterogeneity of molecular dynamics. These effects will be investigated for lipid films of controlled thickness equivalent to few monolayers to submonolayers in submicron cylindrical pores. Proton double-quantum (DQ), triple (TQ) quantum coherences as well as 1H DQ and TQ edited spectra and heteronuclear local filed spectroscopy were used for investigation of surface induced order at different molecular coverage, pore size and temperature. The heterogeneity of molecular dynamics was investigated using magnetization exchange (spin diffusion) technique. A theoretical model adequate for description of this process for grafted molecules was developed. The dynamics of the balk lecithin and lecithin confined in anopore membrane at different concentration was investigated using 31P static and MAS spectra. The heterogeneity of the local mofions along the biomolecule could be also measured using a thermally polarized and hyperpolarized 129Xe.

Publications

• B. Jagadeesh, D.E. Demco, B. Blümich, Surface induced order and dynamic heterogeneity of ultra thin polymer films: a 1H multiple-quantum NMR study, Chem. Phys. Lett., 393, 416 (2004).
  
  
• A. Buda, D.E. Demco, B. Jagadeesh, B. Blümich, Molecular dynamics heterogeneity of confined lipid films by 1H magnetization-exchange nuclear magnetic resonance, J. Chem. Phys-, 122,034701 (2005).
  
  
• B. Jagadeesh, A. Prabhakar, D.E. Demco, A. Buda, B. Blümich, Surface induced molecular dynamics of thin lipid films confined to submicron cavities: a 1H multiple-quantum NMR study, Chem. Phys. Lett., 404, 177 (2005).
  
  
• M. Bertmer, D.E. Demco, M. Wang, C. Melian, R.L Marcean-Chelcea, R. Fechete, M. Baias, B. Blümich, Segmental dynamic heterogeneity of short-chain grafted - poly(dimethylsiloxane) by 1H spin-diffusion NMR, Chem. Phys. Lett. 431,404 (2006).
  
  
• M.A. Voda, D.E. Demco, A. Voda, T. Schauber, M. Adler, T. Dabisch, A. Adams, M. Baias, B. Blümich, Morphology of thermoplastic polyurethanes by 1H spin-diffusion NMR. Macromolecules, 39, 4802 (2006).
  
  
• C. Hedesiu, NMR methods of advanced polymer characterization, PhD Thesis, RWTHAachen, (2007).
  
  
• L. Ufiu, Proton and Xenon NMR on biomolecules, results included in the PhD thesis, RWTH-Aachen (2009).
  
  
• M. Baias, Advanced NMR-methods for characterization of biopolymers, results included in the PhD thesis, RWTH-Aachen (2009).
  
  
• M. Bertmer, M. Wang, D.E. Demco, B. Blümich, Segmental mobility in short-chain grafted-PDMS by homo- and heteronuclear residual dipolar couplings. Solid State Nucl. Magn. Reson. 30, 45 (2006).