Perfused Tumor-Tissue Model for Invasion Analysis

Nieto, Alex; Santos-Heiman, Timothy; Losh, Samuel; Hanemann, Benjamin

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Perfused Tumor-Tissue Model for Invasion Analysis

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Pancreatic cancer is a highly prevalent and invasive form of cancer that, if not properly treated, will metastasize and afflict the remainder of the body. By creating a model that accurately depicts the invasion of PANC-1 cells–a pancreatic cancer cell line–the behavior of pancreatic cancer can be more accurately predicted. The main goals prioritized for this project included fitting the device under a microscope, maintaining a physiologically relevant environment, monitoring cell growth in real time, ensuring the device is easy to operate and handle, and keeping the cost of the device to a minimum. The objectives listed above served as the guiding principles for the design described below. This model was constructed as a perfusion model using a PDMS cell culture housing with a gelatin-chitosan crosslinked hydrogel used to represent the interstitial tissue surrounding a solid tumor. The PDMS housing was cast from a custom 3D printed PLA negative mold designed to promote laminar fluid flow. Fluid flow parameters in line with that of physiological conditions were achieved using a New Era NE-300 syringe pump with 60 mL syringe as a cell media reservoir. A glutaraldehyde-crosslinked gelatin-chitosan hydrogel was formulated and evaluated for various mechanical and material properties representative of interstitial tissue. These material characterization tests included perfusion testing (to determine flow quality), diffusion testing (to determine the transport properties) and rheology testing (to determine stiffness). The PANC-1 cells were formed into spheroids and tested for viability and integrity. Spheroids were evaluated using microscopic analysis using a Keyence All-in One microscope (BZ-X Series) and calcein AM and ethidium homodimer for LIVE/DEAD staining. Viability of the PANC-1 cells on the hydrogel was assessed using a resazurin sodium salt assay. At the conclusion of testing, the iterative design of the housing yielded a shape that was conducive to laminar flow and minimized leaks. A technique to consistently form and transfer spheroids from PANC-1 cells was determined. The hydrogel formulation that was utilized demonstrated good visual properties, but was determined to be a poor analog for interstitial tissue due to material characterization and viability studies demonstrating improper material properties and cytotoxicity due to the presence of unreacted glutaraldehyde. Future teams should strive to improve porosity and viability of the hydrogel scaffold, increase accuracy and reproducibility of tests, and achieve full integration of all design components.

This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.

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