A facile 3D bio‐fabrication of customized tubular scaffolds using solvent‐based extrusion printing for tissue‐engineered tracheal grafts

Abstract

Tracheal implantation remains a major therapeutic challenge due to the unavailability of donors and the lack of biomimetic tubular grafts. Fabrication of biomimetic tracheal scaffolds of suitable materials with matched rigidity, enhanced flexibility and biocompatibility has been a major challenge in the field of tracheal reconstruction. In this study, customized tubular grafts made up of FDA-approved polycaprolactone (PCL) and polyurethane (PU) were fabricated using a novel solvent-based extrusion 3D printing. The printed scaffolds were investigated by various physical, thermal, and mechanical characterizations such as contact angle measurement, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), radial compression, longitudinal compression, and cyclic radial compression. In this study, the native goat trachea was used as a reference for the fabrication of different types of scaffolds (cylindrical, bellow-shaped, and spiral-shaped). The mechanical properties of the goat trachea were also compared to find suitable formulations of PCL=PU. Spiral-shaped scaffolds were found to be an ideal shape based on longitudinal compression and torsion load maintaining clear patency. To check the long-term implantation, in vitro degradation test was performed for all the 3D printed scaffolds and it was found that blending of PU with PCL reduced the degradation behavior. The printed scaffolds were further evaluated for biocompatibility assay, live/dead assay, and cell adhesion assay using bone marrow-derived human mesenchymal stem cells (hMSCs). From biomechanical and biological assessments, PCL70=PU30 of spiral-shaped scaffolds could be a suitable candidate for the development of tracheal regenerative applications.

Tracheal Tissue Engineering: Principles and State of the Art

“…Over time, a wide variety of resorbable materials has been tested with the aim of mimicking native tissues as much as possible; among them, the most common are polycaprolactone (PCL) and polyurethane (PU). These two polymers can be combined in order to modulate the elastic properties and the degradation rate of the scaffold [23].…”

“…Lastly, a scaffold may be composed of multiple layers, where natural and synthetic tissues can be combined in order to overcome their respective limitations; these are referred to as hybrid scaffolds. An example is provided by the study of Ghorbani et al, who fabricated a scaffold whose outer layer was constituted by electrospun nanofibers composed of a blend of collagen and polycaprolactone (PCL), while the inner layer was made of decellularized aorta [23]. By doing so, the authors achieved a TE construct whose inner layer was biocompatible in order to avoid the formation of granulation tissue and favor epithelial cell ingrowth, while the outer layer had optimal mechanical and degradation properties.…”