Membrane proteins play important roles in cell biology and thus it is crucial to
develop methods to access their functional information for further applications such as
drug discovery screening or disease prevention. In order to study membrane species in
their natural structure and functions, we introduce platforms using supported lipid
bilayers (SLB) to house these targeted species. SLBs not only mimic natural cell
membrane environments but also allow heterogeneous bilayer patterning. It is known
that the cell membrane is not merely composed of a well-mixed single lipid phase, but
has distinct lipid micro-domains of co-existing phases, lipid raft and liquid-disorder
phase, and this feature has been suggested to play a key role in regulating several
cellular activities, as some proteins have been shown to exhibit different activity levels
depending on specific lipid interactions.
Therefore, we aim to determine the preference of membrane proteins with lipid
raft phases, and understand the influence of lipid environment on regulating protein
activity level, revealing important mechanisms of membrane proteins function in cells.
Toward this goal, we first patterned two-phase coexistent SLBs inside a microfluidic to
mimic membrane heterogeneities and quantify partition kinetics of membrane-bound
species in this platform (Chapter 2). To further extend the platform to study membrane
protein behavior, we then developed a novel strategy to incorporate membrane proteins
in SLBs without exposing them to harsh detergent to retain their native structure and
functionality. In this dissertation, I will present our advances on using mammalian cell
blebs (Chapter 3) and bacterial outer membrane vesicles (Chapter 4) as an intermediate
to delivery membrane proteins into a SLB. A detailed characterization of bilayer
properties and membrane protein functionalities will also be covered in these chapters.
Finally, in Chapter 5 I will provide a broader view of how our work could be useful to
study and identify the regulatory lipid-protein interactions, which is a pressing issue for
a better understanding of a wide range of biological processes.
Biochemistry; Chemical engineering
Delisa, Matthew; Baird, Barbara Ann
Ph. D., Chemical Engineering
Attribution 4.0 International