Fabrication of flexible thin polyurethane membrane for tissue engineering applications.

Thin and flexible polymeric membranes play a critical role in tissue engineering applications for example organs-on-a-chip. These flexible membranes can enable mechanical stretch of the engineered tissue to mimic organ-specific biophysical features, such as breathing. In this work, we report the fabrication of thin (<20 μm), stretchable, and biocompatible polyurethane (PU) membranes. The membranes were fabricated using spin coating technique on silicon substrates and were mounted on a frame for ease of device integration and handling. The membranes were characterized for their optical and elastic properties and compatibility with cell/tissue culture. It was possible to apply up to 10 kilopascal (kPa) pressure to perform cyclic stretch on 4 mm-diameter membranes for a period of 2 weeks at 0.2 hertz (Hz) frequency without mechanical failure. Adenocarcinomic human alveolar basal epithelial (A549) cells were cultured on the apical side of the PU membrane. The morphology and viability of the cells were comparable to those of cells cultured on standard tissue culture plates. Our experiments suggest that the stretchable PU membrane will be broadly useful for various tissue engineering applications in vitro.