Fluorescence-Based Quantification of Oxygen in Three-Dimensional, Paper-Based Cultures of Mammalian Cells

Our lab is very interested in developing simple tools to study the invasiveness of tumor cells in tissue-like environments.
We utilize paper-based scaffolds to generate our cultures because the material is readily available, easily processed, and accessible to many tissue culture laboratories regardless of their engineering expertise. As we develop these three-dimensional cultures, we are particularly interested in understanding how different environmental factors affect invasiveness (the first step in tumor metastasis).
Oxygen is particularly important because the concentration of oxygen in a tumor mass is much lower than the concentration in the surrounding healthy tissues. We are using our system to ask the question, do cancer cells selectively invade regions with higher oxygen concentrations? To quantify the oxygen in our cultures we have developed thin films, whose fluorescence intensity is dependent on the concentration of oxygen present in the culture. To test our thin films, we use 3D printing to prepare different apparatuses.

Pictured is a flow cell used to monitor the fluorescence of the film in the presence of different concentrations of oxygen.
The other figure shows a 3D mold for polymeric flow cell production. Polydimethylsiloxane (PDMS) flow cell, outlined by the red dashed line, in use with an inverted fluorescence microscope. Gas with varying concentrations of oxygen is delivered to the flow cell, and the emission of the sensor is measured. (Inset) Comparative view of the (left) assembled flow cell, (middle) cured PDMS flow cell before assembly, and (right) 3D printed mold for flow cell production. (Dime for scale)
-Matthew R. Lockett, Lockett Lab, Department of Chemistry
-Matthew Boyce