A microfluidic gradient generator to simulate the oxygen microenvironment in cancer cell culture

Standard cancer lab models lack many attributes of the in-vivo cancer microenvironment. Oxygen levels for example are not commonly controlled in 2D cell-culture well plate experiments. However, low O-2 (hypoxia) in particular is common in cancerous tissue due to high proliferation rates of cancer cells and inadequate vasculature. Hypoxia is also associated with cancer recurrence and drug resistance. We report a microfluidic system capable of exposing a 2D cell-culture to a dissolved oxygen gradient ranging from hypoxia (< 5 mg/L) to byperoxia (40 mg/L) for over 30 min, measurable in real-time using an integrated sensor film. The film incorporates a photostable, non-cytotoxic oxygen-sensitive fluorescent dye, which exhibits a linear response and high contrast (I-0/I-100 = 12) within the range of interest, was integrated onto glass substrates as a cell culture substrate. To demonstrate the applicability of the platform, Ishikawa cancer cells were cultured on the platform and exposed to linear cross-stream oxygen gradients. The platform provides a valuable tool for the culture of cancer cells in an in-vivo like microenvironment and will enable more accurate screening of new anti-cancer drugs.