RESOURCES

Abstract
In this study, a tissue-engineered trachea, consisting of multilevel structural electrospun polylactide (PLA) membranes enveloping 3D-printed thermoplastic polyurethane (TPU) skeletons, was developed to create a mechanically robust, antibacterial and bioresorbable graft for the tracheal reconstruction. The study design incorporated two distinct uses of stereocomplex PLA: patterned electrospun fibers to enhance tissue integration compared to the random layered fibers, meanwhile possessing good antibacterial property; and 3D-printed TPU scaffold with elasticity to provide external support and protection. Herein, ionic liquid (IL)-functioned graphene oxide (GO) was synthesized and presented enhanced mechanical and hydrophilicity properties. More interesting, antibacterial activity of the GO-g-IL modified PLA membranes were proved by Escherichia coli and Staphylococcus aureus, showing superior antibacterial effect compared to single GO or IL. The synergistic antibacterial effect could be related to that GO break cytomembrane of bacteria by its extremely sharp edges, while IL works by electrostatic interaction between its cationic structures and electronegative phosphate groups of bacteria membranes, leading to the loss of cell electrolyte and cell death. Hence, after L929 fibroblast cells were seeded on patterned fibrous membranes with phenotypic shape, further effective cell infiltration, cell proliferation and attachment were observed. In addition, the tissue-engineered trachea scaffolds were implanted into rabbit models. The in vivo result confirmed that the scaffolds with patterned membranes manifested favorable biocompatibility and promoted tissue regeneration.
In this study, a tissue-engineered trachea, consisting of multilevel structural electrospun polylactide (PLA) membranes enveloping 3D-printed thermoplastic polyurethane (TPU) skeletons, was developed to create a mechanically robust, antibacterial and bioresorbable graft for the tracheal reconstruction. The study design incorporated two distinct uses of stereocomplex PLA: patterned electrospun fibers to enhance tissue integration compared to the random layered fibers, meanwhile possessing good antibacterial property; and 3D-printed TPU scaffold with elasticity to provide external support and protection. Herein, ionic liquid (IL)-functioned graphene oxide (GO) was synthesized and presented enhanced mechanical and hydrophilicity properties. More interesting, antibacterial activity of the GO-g-IL modified PLA membranes were proved by Escherichia coli and Staphylococcus aureus, showing superior antibacterial effect compared to single GO or IL. The synergistic antibacterial effect could be related to that GO break cytomembrane of bacteria by its extremely sharp edges, while IL works by electrostatic interaction between its cationic structures and electronegative phosphate groups of bacteria membranes, leading to the loss of cell electrolyte and cell death. Hence, after L929 fibroblast cells were seeded on patterned fibrous membranes with phenotypic shape, further effective cell infiltration, cell proliferation and attachment were observed. In addition, the tissue-engineered trachea scaffolds were implanted into rabbit models. The in vivo result confirmed that the scaffolds with patterned membranes manifested favorable biocompatibility and promoted tissue regeneration.

Abstract
AbstractThe purpose of this study was to evaluate whether the prior implantation of a 3D-printed polycaprolactone (PCL) artificial trachea in the omentum is beneficial for revascularization of the scaffold and reduces associated complications in the reconstruction of a circumferential tracheal defect. Ten New Zealand rabbits were divided into 2 groups: (1) PCL-OC group (PCL scaffold cultured in omentum for 2 weeks before transplantation) and (2) PCL group. In the PCL-OC group, newly formed connective tissue completely covered the luminal surface of the scaffold with mild inflammation at 2 weeks postoperatively; a minor degree of stenosis was noted at 8 weeks postoperatively. The PCL group showed scaffold exposure without any tissue regeneration at 2 weeks postoperatively, and a moderate degree of luminal stenosis 6 weeks after implantation. Histology revealed highly organized regenerated tissue composed of ciliated respiratory epithelium, and submucosal layer in the PCL-OC group. Neo-cartilage regeneration was noted in part of the regenerated tissue. The PCL group demonstrated severe inflammation and an unorganized structure compared to that of the PCL-OC group. In vivo omentum culture of the tracheal scaffold before transplantation is beneficial for rapid re-epithelialization and revascularization of the scaffold. It also prevents postoperative luminal stenosis.