Development of tracheal scaffolds using hybridization of PLLA coil skeleton and electrospun structures

The larynx and the trachea are critical for respiration, airway protection, and phonation in humans. Ideal methods for the reconstruction of the laryngotracheal structure and restoration of laryngotracheal function once the larynx or/and the trachea has been damaged or removed have not yet been developed. Tracheal tissue engineering has been intensively investigated since the first successful human tracheal transplantation was conducted using decellularized tissue implanted with stem cells in 2008. However, the problem of proximal collapse of the graft has recently emerged and there is thus a need for a structurally strengthened scaffold. In this study, decellularized tissue scaffolds were generated using our previously described detergent-free freeze-dry sonication method. Electrospun mats were designed to form tubes. Direct integration of the decellularized tissue with the electrospun mats was unsuccessful, so a poly-L-lactide (PLLA) coil was designed and successfully combined with the outer electrospun fiber sheath. The results of mechanical tests that involved compressing the tube structure revealed significantly greater mechanical strength for the 3-and 1.5-mm-diameter PLLA coiled tubes compared to that of a native tracheal tube. It is therefore possible to construct a hybrid scaffold consisting of an inner PLLA coil skeleton and an outer sheath of electrospun mats, with the decellularized tissue integrated in between these structures.