Doctor of Philosophy (PhD)
Materials Science and Engineering
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Microfluidics, Acoustophoresis, Proteome, Lipidome, Vesicle, Extracellular Vesicle, Cancer, Cell
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Changes in the biomechanical properties of cells accompanying the development of various pathological conditions have been increasingly reported as biomarkers for various diseases, including cancers. In cancer cells, the membrane properties have been altered compared to their healthy counterparts primarily due to proteomic and lipidomic dysregulations conferred by the underlying pathology. The separation and selective recovery of these cells or extracellular vesicles secreted from such cells is of high diagnostic and prognostic value.
In this dissertation, the research builds on thermally-assisted acoustophoresis technique which was developed in our laboratory for the separation of vesicles of the same size, charge and shape yet with varying physical properties. This technique uses the inherent thermotropic behavior of lipid membrane to identify a distinct acoustic contrast temperature (Tϕ) for each individual composition under acoustophoresis. By tuning the temperature, the acoustic contrast factor (Φ) of vesicle systems experience a signature temperature at which sign of Φ switches from positive to negative. This temperature is defined as the acoustic contrast temperature, Tϕ. Since various vesicles systems have distinct Tϕ values, it allowed the development of a separation method of vesicles based on their membrane properties, with target outlet purities exceeding 95%.
Over-expression and under-expression of proteins play crucial roles in the functionality of cells and can be indicators of pathological disorders. Using systematic designed experiments, the effect of membrane protein content in vesicles was studies. Using three different transmembrane peptides (gramicidin, alamethicin and melittin), the thermo-acoustofluidic properties of vesicles were studied in an in-house built lab-on-chip to assess the separation efficiencies for various protein contents.
To demonstrate the utility of this method and its performance on real biological samples, the effect of proteins on thermally-dependent acoustic properties of red blood cells were investigated. The separation of red blood cells based on expressed membrane proteins of different contents proved to yield to distinctive Tϕ values that afforded the separation of the cells. The simplicity, rapidity, and label-free nature of this approach holds promise as a diagnostic and separation tool for cells affected by diseases that affect the physical properties of membrane and extracellular vesicles such as exosomes and microvesicles.
Mirtaheri, Elnaz, "The Effect of Proteome and Lipidome on the Behavior of Membrane Bound Systems in Thermally-Assisted Acoustophoresis" (2019). FIU Electronic Theses and Dissertations. 4056.
Biology and Biomimetic Materials Commons, Biomedical Devices and Instrumentation Commons, Biophysics Commons, Other Cell and Developmental Biology Commons, Other Materials Science and Engineering Commons
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