Rapid manufacturing techniques for the tissue engineering of human heart valves.

Three-dimensional (3D) printing technologies have reached a level of quality that justifies considering rapid manufacturing for medical applications. Herein, we introduce a new approach using 3D printing to simplify and improve the fabrication of human heart valve scaffolds by tissue engineering (TE). Custom-made human heart valve scaffolds are to be fabricated on a selective laser-sintering 3D printer for subsequent seeding with vascular cells from human umbilical cords. The scaffolds will be produced from resorbable polymers that must feature a number of specific properties: the structure, i.e. particle granularity and shape, and thermic properties must be feasible for the printing process. They must be suitable for the cell-seeding process and at the same time should be resorbable. They must be applicable for implementation in the human body and flexible enough to support the full functionality of the valve. The research focuses mainly on the search for a suitable scaffold material that allows the implementation of both the printing process to produce the scaffolds and the cell-seeding process, while meeting all of the above requirements. Computer tomographic data from patients were transformed into a 3D data model suitable for the 3D printer. Our current activities involve various aspects of the printing process, material research and the implementation of the cell-seeding process. Different resorbable polymeric materials have been examined and used to fabricate heart valve scaffolds by rapid manufacturing. Human vascular cells attached to the scaffold surface should migrate additionally into the inner structure of the polymeric samples. The ultimate intention of our approach is to establish a heart valve fabrication process based on 3D rapid manufacturing and TE. Based on the computer tomographic data of a patient, a custom-made scaffold for a valve will be produced on a 3D printer and populated preferably by autologous cells. The long-term goal is to support the growth of a new valve by a 3D structure resorbed by the human body in the course of the growth process. Our current activities can be characterized as basic research in which the fundamental steps of the technical process and its feasibility are investigated.