Living systems and liquid crystals

Abstract

The chemical, physical and electrical properties of naturally occurring liquid crystals are fundamentally linked to the functions of certain biological systems. This review focuses primarily on the liquid crystalline properties of cell membranes and the two-dimensional smectic A model used to describe the lipid bilayer structure that it forms. The composition of mammalian cells is considered along with the effects that disease has on the changes to the molecular composition, and the elastic and electrical properties of the cell membrane. Particular emphasis is given to the role that the flexoelectric effect in a two-dimensional lipid bilayer plays in mechanotransduction (the conversion of a mechanical stimulus to an electrical signal) in living systems. The intrinsic electrical properties arising from the membrane composition itself in terms of the transmembrane, surface and membrane dipole potential are considered in relation to the liquid crystalline structure of the cell membrane and the latest measurement techniques for the measurement of membrane electrical potentials are presented.

Keywords:

• liquid crystal
• cell membrane
• lipid bilayer
• flexoelectric effect
• membrane dipole potential

Acknowledgements

The author gratefully acknowledges funding from the Royal Society through a University Research Fellowship for the original work presented in Section 4.3.