Rapid Prototyping a Double-layer Polyurethane-collagen Conduit and its Schwann Cell Compatibility

A new double-layer conduit that combined an outer synthetic polyurethane (PU) layer and inner natural collagen layer was fabricated via a double-nozzle low-temperature deposition manufacturing (DLDM) technology. The outer PU layer provided a mechanically stable tunnel against scar tissue invasion in vivo, while the inner collagen layer promoted Schwann cell adhesion, migration, and proliferation. Microporous structures were found in both the layers. A tight connection between the double layers was achieved by adjusting the distance between the two deposit nozzles and adjusting other processing parameters. Schwann cells from rat sciatic nerves were cultured in the layered PU-collagen conduits for one week; a significant enhancement in their retention and viability was seen compared to those made of pure PU. The poly(urethane collagen) double layer conduit had better Schwann cell compatibility and so has a great potential use in clinical peripheral nerve repair.