Gigahertz spectroscopy of hydrated polyunsaturated phospholipid membranes : an investigation of dielectric properties

• Main Author: Kurylowicz, Martin
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/14537

An experimental technique was developed to measure the complex dielectric constant for small volumes of lossy liquids between 45 MHz and 50 GHz, and from 5°C to 55°C. The study was motivated by a desire to investigate the role of water in biological materials, and to explore the relevance of dielectric properties to fundamental questions in biophysics. Bulk samples of hydrated phospholipid membranes were used as a model system in which water plays a significant role, and polyunsaturated membranes were tested in comparison with saturated and mono-unsaturated model membranes. Membranes containing DHA (22:6) were of special interest since their biological role is suggestive of interesting electric or dielectric properties. The technique proved to be effective in resolving phase transitions, the degree of hydration, the presence of macroscopic dielectric domains which are indicative of heterogenous structure, and diagnosing relaxation and conduction mechanisms.