Rapid continuous 3D printed multi-channel poly(ethylene glycol) diacrylate/chitosan nerve guidance conduit: In vivo study.

Digital light processing (DLP) 3D printing is a rapidly expanding technique in nerve tissue engineering, advancing towards fabricating nerve guidance conduits (NGCs). However, lack of bioink with printability and admirable biological features is the challenging engineering issue in this method. In this study, DLP based printing of multi-channel NGCs for peripheral nerve rehabilitation using polyethylene glycol diacrylate (PEGDA) hydrogel containing chitosan (0, 12.5, 25 and 50 wt%) biological cue is presented. Multi-channel NGCs with desired patterns are successfully printed and characterized. Incorporation of 12.5 wt% chitosan assists to fabricate PEGDA-based scaffold with better printed accuracy in terms of channel diameter (477 ± 20 μm) and pore size (377 ± 9 μm), higher porosity (80 ± 5 %) and acceptable mechanical features than pristine PEGDA scaffold. In vivo results in a rat model show reconstruction of axons through the multi-channel 3D printed PEGDA/chitosan NGCs into the distal stump after 8 weeks due to the effective directional guidance of regenerating sciatic nerves. Moreover, incorporation of 12.5 wt% chitosan to the PEGDA, drastically diminishes the inflammatory cells in the in vivo assay. Such intriguing method has a high potency to fabricate intricate multi-channel NGCs in a rapid and precise manner which can promote nerve reconstruction.