Interfacial science of phospholipid assemblies on solid supports
Jackman, Joshua Alexander
Date of Issue2015
School of Materials Science and Engineering
The interfacial science of phospholipid assemblies on solid supports is principally governed by a set of fundamental forces that exists in all colloidal and interfacial systems. In this thesis, the objective is to investigate how the interplay of different interfacial forces contributes to the fabrication and stabilization of phospholipid assemblies, including adsorbed vesicles and supported lipid bilayers. The overall hypothesis is that the adhesion of phospholipid assemblies on solid supports can be rationalized by taking into account the fundamental material properties of the system and corresponding experimental parameters. A combination of experimental and theoretical approaches is employed, leading to new physical insights into the contributions of the different interfacial forces as well as methods to controllably fabricate phospholipid assemblies. In the first part, two studies are reported clarifying the role of two experimental parameters, osmotic pressure and vesicle lamellarity, in the fabrication of supported lipid bilayers on silicon oxide. In the second part, two additional studies investigate the factors behind the difficulty to fabricate supported lipid bilayers on titanium oxide and aluminum oxide. It is identified that the hydration force plays a governing role to influence the lipid-substrate interaction on both substrates, and it is demonstrated that bilayer formation on aluminum oxide can be achieved by solvent-assisted lipid self-assembly. In the third part, a set of three studies extends the application of localized surface plasmon resonance sensors to track vesicle adsorption and rupture, including factors such as the adsorption rate and substrateinduced deformation of adsorbed vesicles at low surface coverage. In summary, the findings presented in this thesis demonstrate the collective importance of the interfacial forces for the fabrication and stabilization of phospholipid assemblies on solid supports, and offer integrated approaches for scrutinizing the adsorption of biological macromolecules in general.