Preparation of mineralized pericardium by alternative soaking for soft–hard interregional tissue application

Recent applications of decellularized tissues include the ectopic use of sheets and powders for three-dimensional (3D) tissue reconstruction. Decellularized tissues are modified (or fabricated) with the desired functions for application to the target (transplanted or used) tissue, including soft–hard interregional tissues, such as ligaments, tendons, and periodontal ligaments. This study aimed to prepare a mineralized decellularized pericardium to construct a soft-hard interregional tissue by 3D fabrication of decellularized pericardium, for example, rolling up to a cylindrical form. The decellularized pericardial tissue was prepared using the high hydrostatic pressurization (HHP) and surfactants method. The pericardium consisted of bundles of aligned fibers, and the bundles were slightly disordered when prepared with the surfactant decellularization method compared with that prepared using the HHP decellularization method. Mineralization of the decellularized pericardium was performed using an alternate soaking process with various cycles. The surface of the decellularized pericardium was covered with calcium phosphate precipitates, which accumulated on the surface with an increasing number of soaking cycles. The inside of the HHP decellularized pericardium was mineralized uniformly, whereas the mineralization of the decellularized pericardium decreased toward the interior. These findings suggest that the decellularization method strongly affects the structure and mineralized parts of the decellularized pericardium. The mineralized decellularized pericardium could be a candidate material for reconstructing alternative interregional tissues, such as ligaments and tendons.