A small cut on the finger, a scraped knee or a scratch on the surface of the skin - the human body heals itself, small wounds apparently close without help. How can these self-healing powers be used in regenerative medicine? The research project "Patient-Specific Implants from Autologous Blood Donations" at the Institute of Multiphase Processes (IMP), which is based at the Faculty of Mechanical Engineering, addresses this question. The project has received funding of 88,000 euros over two years within the scope of the new programme Leibniz Young Investigator Grants initiated by Leibniz University Hannover.
"Existing implants save lives, however, they cannot fully regenerate parts of the human body", says Dr.-Ing. Marc Müller, chief engineer at the IMP, who supervises the project. The healing process of the body can be facilitated, however implants still consist of materials foreign to the body, which are not equally tolerated by all patients. The benefits of customised implants are clearly evident: A prosthesis would not be detected as foreign material, which virtually eliminates the occurrence of intolerances.
In order to achieve this - for example when replacing blood vessels - researchers intend to take advantage of the characteristics of human blood coagulation to develop implants out of the body''s own material - in this case blood. If skin is injured, the body closes the wound in order to stop loss of blood as well as to prevent foreign matter from entering the wound. During this process, blood platelets - or "thrombocytes" - change their form. A tiny flat disc turns into a structure resembling a sea urchin: A sphere with long, web-like threads growing on its surface.
The activated thrombocytes join and initially form a scaffold-like structure. In the second phase, the structure solidifies through specific blood proteins. These proteins position themselves around the scaffold-like structure like glue - comparable to mortar holding together the bricks of a wall. While changing their form, thrombocytes transmit specific chemical messengers that facilitate the growth of vessel cells.
The idea is to use the principle of coagulation and vessel regeneration to make prostheses such as blood vessel prostheses, in order to replace injured or closed vessels. In initial experiments, researchers were able to produce porous supporting structures out of blood proteins from pig blood, which contained growth factors from thrombocytes. The next crucial step is to solidify the structure so that it remains solid inside the body for the desired period of time. In order to achieve this, researchers intend to develop a new method that cross-links supporting structures by using the natural coagulation process.
The long-term objective is a concept for developing devices that create customised implants out of autologous blood. Thus, implants could be made in hospitals right before operations.
Note to editors:
For further information, please contact Dr.-Ing. Marc Müller, Institute of Multiphase Processes at Leibniz University Hannover (Tel. +49 511 762 3639, Email mueller@imp.uni-hannover.de).
