The high outflow permeability of the nerve conduit used to emit the drained waste generated from the traumatized host nerve stump is critical in peripheral nerve regeneration. Our earlier studies have established that asymmetric conduits fulfill the basic requirements for use as nerve guide conduits. In this study, two-ply structures were prepared by particulate leaching techniques to fabricate controllable asymmetric polycaprolactone (PCL) discs. Salt crystals (0 μm, ＜37 μm and 100 μm) were utilized to form asymmetric PCL-00, PCL-037 and PCL-0100 discs. These PCL discs had the same crystallinity as pure PCL, which was determined by differential scattering calorimetry (DSC). The dynamic mechanical analysis (DMA) showed that the stress decreased with the adding of salt crystals. In the in vitro trial, C6 rat glial cells and L929 stromal cells were seeded on the macro- and micro-porous sides of an asymmetric disc, respectively. The disc was maintained within a designed co-culture system that simulated the repaired nerve conduit environment. The results for the PCL-037 disc indicated statistically significant proliferation of C6 cells and the inhibition of the division of L929 cells in cell numbers and lactate dehydrogenase (LDH) release, compared with the PCL-00 and PCL-0100 discs. In this work, particulate leaching and dip-coating techniques afforded promising methods for fabrication of controllable asymmetric PCL membranes. The directional transport characteristics were established to be extremely important to the design and development of optimal nerve guide conduits.
