The spatiotemporal organization of membrane proteins is implicated in cellular trafficking, signalling and reception. It was proposed that biological membranes partition into lipid rafts that can promote and control the organization of membrane proteins to localize the mentioned processes. Lipid rafts are thought to be transient (microseconds) and small (nanometers), rendering their detection a challenging task. To circumvent this problem, multi-component artificial membrane systems are deployed to study the segregation of lipids at longer time and length scales. In this thesis, multi-component Droplet Interface Bilayers (DIBs) were imaged using fluorescence and interferometric scattering microscopy. DIBs were used to examine and manipulate microscopic lipid domains and to observe, for the first time, transient nanoscopic lipid domains. The techniques and results described here will have important implications on future research in this field.

Hollow fiber membranes (HFMs) formed through phase inversion methods exhibit specific physicochemical characteristics and generally favorable surface and mechanical properties, supporting their use in diverse applications including ultrafiltration, dialysis, cell culture, bioreactors, and tissue engineering. Characterization of, and modifications to, such membranes are important steps in achieving desired characteristics for specific applications. HFMs subject to gas, irradiation, and chemical sterilization techniques were characterized based on several analytical techniques. It was revealed that these common sterilization techniques can cause inadvertent changes to HFM properties. While these changes may cause detrimental effects to HFMs used in filtration, the methods of sterilization are also presented as a facile means of tuning properties toward specific applications. Modifications to HFM surface chemistries were also sought as a method of adsorbing bacterial lipopolysaccharide (LPS) from solutions used in hemodialysis treatments and bioprocessing applications. It was found that additives such as polyvinylpyrrolidone (PVP), polyethyleneglycol (PEG), and poly-L-lysine (PLL) can facilitate adsorption capacities of HFMs toward LPS. Additionally, chemical changes are presented as a means of preferentially adsorbing LPS to specific locations on the HFM surface.