Narendra Pandala - PhD Proposal Defense

In the past decade, the cases related to conditions of the gastrointestinal tract have been increasing steadily, with an estimated 8.6 million individuals visiting the emergency room for issues involving the digestive system in 2014 alone. Even though most of these conditions are not life threating, they have a significant impact on the lifestyle of the individual and there is no cure for some of them. The in vitro colon models play a significant role in not only understanding these conditions related to the GI tract and drug screening but also testing the permeability of the orally administered drugs. The in vivo colon epithelium constitutes a complex 3D architecture in the form of crypts, with a plethora of cells performing digestive, transport and immune related functions. Traditional in vitro colon models fail to replicate this 3D structure and have low expression levels of some of the enzymes and mucus production, limiting their accuracy in replicating the in vivo environment. To create a 3D in vitro model mimicking the architecture of the colon we have developed a screen-printing process to print layers of cells supported by a hydrogel scaffold. The objective of this proposed research is to develop a physiologically focused in vitro model of the colon for high throughput screening, using the screen printing process. We hypothesize that the screen printing process will provide an inexpensive technique to print layers of cells along with the hydrogel scaffolds to develop in vitro models which could better mimic the in vivo microenvironment. To develop the in vitro model of the colon using the screen printing process, we propose the following aims: 1) To synthesize and characterize a chemically crosslinking hydrogel to be used as the bioink in the screen printing process. 2) To optimize the screen printing process, determine the optimal printing setup, and determine the optimal bioink composition for the cells. 3) To create a physiologically focused in vitro colon model using the screen printing process with the hydrogel scaffold as the bioink.