The innovation engine for new materials

Elizabeth Eck

CISEI Intern


University of California, Santa Barbara


CCS Physics and CCS Biology

Site Abroad: 

Chalmers Institute of Technology, Gothenburg, Sweden


Dr. Hudson Pace

Faculty Sponsor(s): 

Professor Fredrik Höök

Faculty Sponsor's Department: 


Project Title: 

The characterization of vesicle mixing via bath sonication

Project Description: 

Biosensors are valuable tools for studying pathogens and pharmaceuticals. Utilizing native membranes in the construction of biosensors is attractive due to the natural occurrence of important, native receptors. Supported lipid bilayers (SLBs) have been widely employed as biosensor platforms due to their homology with the cell surface. However, major challenges exist in current strategies employed to create functional SLB biosensors from native membranes. These challenges are addressed by the addition of lipids that more readily form SLBs via vesicle fusion. Additionally, membrane protein mobility is promoted by the use of polymer cushions to separate SLBs from the underlying substrate. We describe and characterize a methodology which utilizes bath sonication to fuse native membrane vesicles with vesicles containing both PEGylated-lipids and lipids which promote SLB formation. Model vesicles are utilized to understand the importance of temperature, time, and other parameters on the sonication-facilitated vesicle fusion process. Vesicles containing lipids labeled with a FRET pair are used to indicate the degree of vesicle fusion. Findings indicate that a low temperature during sonication slows vesicle fusion at sonication times less than 10 minutes. Lipid phase does not affect fusion rates. Full mixing is achieved after 10 minutes of sonication in all systems studied. During sonication, small volumes, less than 50µL, inhibit vesicle fusion. Vesicles become larger and the size distribution of the population becomes polydisperse after sonication. Signal loss, apparent after sonication times longer than 10 minutes, is most likely due to fluorescent dye degradation during sonication.