Microfluidic cell culture system for in vitro model study of human intestinal follicle-associated epithelium

Abstract

The intestinal follicle-associated epithelium (FAE) of gut poses immunological importance as its role is to sense luminal antigens. The complexity of FAE was simplified as the co-culture of Caco-2 and Raji cell lines on a Transwell. The Transwell FAE model elucidated the involvement of Raji cell migration to the FAE-like functionality, yet live-cell monitoring was limited. This thesis describes a novel microfluidic cell culture system (MCCS) for studying Raji dynamics with live-cell monitoring. The MCCS is integrated into a commercial well plate for enhanced usability and maintenance of microvolumetric cell culture. In vitro FAE characteristics were validated with the increased measurement of Caco-2 permeability and the direct observation of Raji cell invasion to Caco-2 culture. Raji migratory behavior of the microfluidic FAE model in the MCCS displayed a 3.6 fold increase in directionality towards Caco-2, which concurred with the Raji translocation to Caco-2 layer reported in the Transwell model. Microcompartments were incorporated to the MCCS to provide controlled microenvironments for Raji cells. The enhanced functionality of the MCCS enabled periodic media exchange, allowing live-cell monitoring for an extended period. Investigation of the Raji migratory dynamics revealed higher motility and proliferation in the microenvironment encased with the 500 μm long microcompartments. Reciprocating migration of Raji cells was observed in the extended live-cell monitoring, which bared a resemblance to B lymphocytic migration occurring in actual tissue. Changes in the cellular behaviors of Caco-2 and Raji cells were investigated simultaneously concerning the effect of pro-inflammatory agents on the microfluidic FAE. The vesicular communication of the in vitro FAE was distinguished with massive streams of granular bodies emanating from Raji cells. The MCCS developed in this thesis is expected to be a novel apparatus for investigating biological phenomena of the microfluidic FAE model such as antigen response and vesicle-mediated cellular interactions.