BME PhD Proposal Presentation: Ut-Binh T. Giang

Utilization of Microbubble Formation in Polydimethylsiloxane to Create Micrometastases-Like Cell Cultures for More Effective Drug Screening

Supervised by Lisa DeLouise, Ph.D. and Mike King, Ph.D.

Abstract

Current research using 3D cell culture constructs attempts to mimic the conditions of cancer cells in vivo in order to deduce their behavior following exposure to an exogenous substance, such as a chemotherapeutic agent. Three-dimensional cell culture is believed to be a more valid representation of cell growth and proliferation inside the body compared to standardized 2D tissue culture. Evidence suggests that microtumors in vivo are characterized by limitation of drug penetration, hypoxic conditions in the region of solid tumors, and the need for vascularization. There are many different 3D constructs used in cell research including the hanging drop method, spinner flasks, hydrophobic gels, and microwells. These techniques induce 3D multi-cellular formation by various means such as suspension, mechanical spinning, surface tension, and micro-sized cavities, respectively. However, common drawbacks for these models are complications for long term cell culture, excessive external force used to form the 3D cultures, and limited application after initial seeding. In this proposal, we will introduce the novel gas expansion molding (GEM) technique that forms spherical structures termed microbubbles in polydimethylsiloxane (PDMS) polymer. The unique geometry of these microbubbles can intrinsically induce spheroidal formation of some cells incubated in them.

This proposed research consists of steps to validate:

1. the utility of microbubbles in PDMS as a means of cell culture compartments,
2. the homogenous seeding and proliferation of cells inside the microbubble, and
3. the use of these micro-metastatic like cell clusters in a multi-drug screening assay.

The cell lines that will be investigated are three adherent dermal cell lines (YUSIK melanoma, HaCaT immortalized keratinocytes and SCC skin cell carcinoma). We hypothesize that cell colonies of YUSIK, HaCaT and SCC grown in microbubbles in PDMS are more representative of micrometastases in vivo than in 2D cell culture and other 3D rectilinear geometries, thus, drug screening employing these microtumors will yield new information about therapeutic drugs that are more indicative of the real-life responses of cells exposed to them in the body.