3D-Printed Dextran/PCL Bilayer Tubes Supporting Neural Cell Viability for Peripheral Nerve Repair

Peripheral nerve injuries often cause long-term functional deficits. This work presents a double-layer nerve guidance tube produced by 3D extrusion printing, combining a PCL-based outer layer with a dextran-based inner hydrogel containing N2a cells. Three PCL/PEGDA formulations (35PCL2k:65PEGDA, 50PCL2k:50PEGDA and 40PCL2k:40PEGDA:20PCL530) were developed, enabling scalable fabrication of dextran/PCL conduits while eliminating DMSO use and its associated post-processing. The inner 20Dex:5HAMA:10GelMA hydrogel was optimized through iterative testing. Comprehensive physicochemical, mechanical, and cytotoxic analyses revealed that all PCL-based formulations exhibited similar behavior, with 50PCL2k:50PEGDA exhibiting superior mechanical strength and cytocompatibility. As expected, 20Dex:5HAMA:10GelMA displayed lower mechanical resistance and faster degradation but strongly supported cell viability and proliferation. Both inks were successfully printed into a bilayer tube that demonstrated high resistance in a suturability test, withstanding the suturing procedure without tearing or deformation. These results highlight the strong potential of this system for future in vivo nerve regeneration studies.