Chapter 1
Introduction
1.1 Scopeandlayoutofthisthesis
This thesis presents a study of interfacial lipid membrane electrostatics using atomic
force Microscopy (AFM). The specific problem described and solved herein is the
experimental observation of charge regulation due to the mobility of lipids. Chapter 1 of
this thesis introduces the lipid bilayer membrane and discusses its importance in a
biological Context-Specifically focusing on the electrostatics of the membrane. Chapter 1
also gives an overview of biological AFM and of its usage in the study of membrane
electrostatics in particular. Chapter 2 of this thesis reviews previous work [1] on using
AFM in quantitative membrane electrostatics and discusses the limitations of that work.
Chapter 2 provides context for and is the starting point of the original work performed in
Chapter 3. In addition to extending the methods used in the preceding chapter, Chapter 3
presents the first experimental observation of mobile lipid charge regulation.
1.2 Lipid bilayer membranes
Lipid bilayer membranes form the boundary of many biological entities such as cells,
organelles and viruses. These membranes are on the order of 5 nm in transverse thickness
and can range up to many microns laterally. Lipid membranes are highly impervious to
aqueous soluble molecules and ions, and therefore form a dynamic barrier between the