Application of Polymethylpentene, an Oxygen Permeable Thermoplastic, for Long-Term on-a-Chip Cell Culture and Organ-on-a-Chip Devices

Abstract

The applicability of a gas-permeable, thermoplastic material polymethylpentene (PMP) was investigated, experimentally and analytically, for organ-on-a-chip (OoC) and long-term on-a-chip cell cultivation applications. Using a sealed culture chamber device fitted with oxygen sensors, we tested and compared PMP to commonly used glass and polydimethylsiloxane (PDMS). We show that PMP and PDMS have comparable performance for oxygen supply during 4 days culture of epithelial (A549) cells with oxygen concentration stabilizing at 16%, compared with glass control where it decreases to 3%. For the first time, transmission light images of cells growing on PMP were obtained, demonstrating that the optical properties of PMP are suitable for non-fluorescent, live cell imaging. Following the combined transmission light imaging and calcein-AM staining, cell adherence, proliferation, morphology, and viability of A549 cells were shown to be similar on PMP and glass coated with poly-L-lysine. In contrast to PDMS, we demonstrate that a film of PMP as thin as 0.125 mm is compatible with high-resolution confocal microscopy due to its excellent optical properties and mechanical stiffness. PMP was also found to be fully compatible with device sterilization, cell fixation, cell permeabilization and fluorescent staining. We envision this material to extend the range of possible microfluidic applications beyond the current state-of-the-art, due to its beneficial physical properties and suitability for prototyping by different methods. The integrated device and measurement methodology demonstrated in this work are transferrable to other cell-based studies and life-sciences applications.

Scalable Processing of Cyclic Olefin Copolymer (COC) Microfluidic Biochips

“…With this low gas permeability, the gas bubbles present do not pass through the COC material and will eventually leave the channel carried by the flowing fluid. In PDMS, the gas permeability is reported to be between 523 barrer [47] and 733 barrer [48] at 35-37 °C. In PDMS, it was observed that bubbles formed continuously through the entire length of the channel.…”

“…With this low gas permeability, the gas bubbles present do not pass through the COC material and will eventually leave the channel carried by the flowing fluid. In PDMS, the gas permeability is reported to be between 523 barrer [47] and 733 barrer [48] at 35-37 • C. In PDMS, it was observed that bubbles formed continuously through the entire length of the channel. Due to the high gas permeability of PDMS, the air trapped inside the channel can pass through the material, but it also be renewed due to the device being in contact with air, allowing a continuous formation of bubbles.…”