The liposomes are well‐known lipid aggregates. The lipid composition and size of the liposomes can be controlled. The method of preparation, lipid composition, temperature, and pH have an influence on the liposome size and bilayer structure. The physicochemical properties of liposomes allow them to various applications. Nuclear magnetic resonance (NMR) is one of the methods used to study liposome properties. The abilities of the method are the high sensitivity and high resolution. Moreover, it provides information about dynamics and structure of molecules. 1H and 31P NMR are most convenient methods to study liposomes, because liposomes are typically formed from phospholipids. Additionally, two‐dimensional NMR spectroscopy reveals information about the nature of intermolecular and intramolecular interactions (scalar and dipole‐dipole interactions) that makes easier to interpret the structure of molecules. The chapter aims to introduce the NMR phenomenon, interactions between spins in magnetic field, dynamics of molecules and physical parameters of NMR spectra, and the necessary information for analyzing and interpreting high‐resolution NMR spectra. It also aims to show how various changes in the bilayer structure or dynamics of lipid molecules are visible in the NMR spectra.
Part of the book: Liposomes
Amphiphilic molecules can create various aggregates in water. Concern about exploring such structures has been unabated for several decades due to the wide range of possible applications of lipid aggregates, from food technology to the pharmaceutical industry. The form of self-assembled structures depends on many factors, such as the type of amphiphilic molecule, the concentration, the level of hydration, the temperature, and the pH. Liposomes and micelles are the most widely known types of closed structures. Liposomes are more often used in the fields of medicine and pharmacy because they consist of nontoxic compounds and their composition and size can be controlled. Nuclear magnetic resonance (NMR) is one of the methods, which is most commonly used to study liposome properties. It can be used to observe changes in the structure, dynamics, and phase transition of lipid membranes. The membrane properties are changed under the influence of external factors, such as temperature, pH, and the presence of ions or drugs. The chapter aims to introduce and discuss the possibilities of the most useful NMR methods, 31P and 1H, to study the liposome properties. It also aims to show how various changes in the structure or dynamics of lipid molecules are visible in the NMR spectra.
Part of the book: Spectroscopic Analyses