TeraHertz Dielectric Relaxation of Biological Water Confined in Model Membranes made of Lyotropic Phospholipids

Abstract

Understanding water-membrane interactions is a fundamental issue in biophysics since these interactions are at the basis of many key molecular processes occurring in membranes. The hydrogen-bond network of water molecules is highly dynamic and its dynamical structure influences membrane fluidity and proton transport across membranes. We investigate the dynamics of water hydrogen-bonds network in model membranes using dielectric relaxation spectroscopy in the TeraHertz range. This frequency interval is suitable for obtaining information on the collective low-energy modes of the hydrogen-bond network of water molecules. In this paper we review the technique and present some preliminary experimental results.

Keywords:

• bound water
• confined water
• dielectric relaxation
• DOPC
• lyotropic liquid crystals
• phospholipids
• THz time domain spectroscopy

Acknowledgments

Domenico Paparo must thank the European Commission for supporting this work with a Marie Curie grant (Project: TERASPIN 039223). This work is part of the research program of the ‘Stichting voor Fundamenteel Onderzoek der Materie (FOM)’, which is financially supported by the ‘Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO)’.