(Georgia Institute of Technology, 2020-12)
Slyman, Raleigh James Hudson
Human intestinal organoids (HIOs) are 3-dimensional aggregates of cells that can replicate the structure and function of the human gastrointestinal system. HIOs generally resemble fetal tissue, so efforts have been made to mature them such that they replicate adult gastrointestinal physiology. Previous studies have shown HIO maturation following an injection of E. coli into the HIO lumen but did not attempt to regulate E. coli populations thereafter. This thesis presents a perfusion system which has the potential to modulate a luminal bacteria population through fluidic transfer. The system consists of a double-barrel glass capillary connected to a pressure-based pump, which allows for high temporal control of fluid flow. The system has been shown to regulate the concentration of diffusible dye molecules in the lumen and partially regulate E. coli distributed heterogeneously in the lumen. If volumetric flow control and incubator compatibility are implemented, the new proposed system may enable long-term study of HIO-E. coli interaction.
(Georgia Institute of Technology, 2020-05)
Pavlidis, Despina
Development of a bacterial culture platform which accounts for the characteristic human gut oxygen gradient could allow for improved understanding of the gut microbiome and its implications in human health as well as targeted therapies for related diseases. This work presents a microscale bacterial culture platform in an aqueous two-phase system (ATPS) with integrated oxygen-sensing microbeads. Generation of the oxygen gradient is explored through the culture of the facultative bacterium, Escherichia coli (E. coli), within the platform. Growth characterization of GFP-expressing E.coli O157:H7 within the platform is achieved through time lapse measurements of oxygen consumption and GFP fluorescence, as well as plate counting data. Phase fluorimetry measurements are collected through the oxygen-sensing microbeads placed at the bottom of the culture wells. Results indicate that E.coli was able to grow in the ATPS culture environment and that near anaerobic conditions were achieved at the bottom of the culture wells. Oxygen concentration information is restricted to the bottom of the culture wells due to microbead placement; however, in future iterations, this platform could accommodate other types of bacteria such as aerobic and anaerobic bacteria.