Novel Lipid Nanoassemblies with Advanced Functionality: Design, Photosynthesis Mimicking and Self-Assembly

Abstract

Model lipid membranes have attracted considerable attention over the past several decades. They are ideal biomimetic models for studying cells and cellular processes. Due to their unique properties and functional versatility, they are widely used for drug delivery, biosensors and photosynthetic mimics. In this dissertation, we first demonstrated artificial photosynthetic mimics to mimic photosynthesis of green sulfur bacteria by using model lipid membranes including liposomes and solid supported lipid bilayers as scaffolds to host essential components for photoconversion. We specifically investigated the effect of different lipid phases such as lipid disorder phase, lipid ordered phase, gel phase on the photoconversion efficiency. We observed by incorporation of cholesterol, the photoconversion efficiency is greatly enhanced. The underlying photo-kinetics and morphology of such photosynthetic mimics are characterized by absorption spectroscopy, fluorescence spectroscopy, transient absorption spectroscopy, atomic force microscopy, scanning electron microscopy, and confocal microscopy. We next synthesized various kinds of Janus-like giant liposomes, exploiting cholesterol-induced phase separation. We specially investigated the self-assembly of biotinylated Janus-like liposomes and charged Janus-like liposomes, which is driven by biotin-avidin interaction and electrostatic interaction, respectively. By taking advantage of cholesterol-induced phase separation, we can regioselectively dope the biotinylated lipids and charged lipids into the desired domains. Using such Janus-like liposomes, we can obtain well controlled self-assembled lipid supercomplexes.