Project Details
Projekt
Additive manufacturing of personalized bone implants based on calcium magnesium phosphates for applications in human and veterinary medicine
Subject Area
Biomaterials
Veterinary Medical Science
Veterinary Medical Science
Term
from 2019 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 417069397
Currently available synthetic bone grafts are based on calcium phosphates (CaP) and show often an insufficiently solubility under physiological conditions and heal under the formation of an osseoceramic composite. In particular, the treatment of segmental bone defects is difficult, since most bone graft are missing a dimensional stability or are only available as simple formed monoliths. In response to these requirements, the project aims at the additive manufacturing of fast degradable magnesiumdoped CaP-cements by means of 3D powder printing, to produce personalized bone implants with an optimized degradation profile regarding osteogenesis. A high osseoregenerative potential of bioceramics will be achieved by a defect-specific macroscopic structure and the similarity of the microstructure and chemical composition to bone. Cement powders with the general chemical composition CaxMg3-x(PO4)2 will be used as raw materials, whereas the substitution of CaP with Mg will result in an increased mechanical stability. Moreover, the Ca:Mg ratio will be used for the adjustment of the degradation rate. The powder-printed CaMgP-structures will be sintered, resulting in a highly stable ceramic of in vivo moderately soluble phases (Mg3(PO4)2, Ca3(PO4)2, Ca9 Mg(HPO4)6). By immersion of the structures in reactive solutions, the ceramic network will be coated with highly soluble phases (NH4MgHPO4*6H2O, MgHPO4*3H2O, CaHPO4*2H2O) in response to a solution-precipitation process. By this quantitatively absorbable implants should be created, which show an in-vivo-stability of adequate duration with an opposite behaviour to bone regeneration. CaMgP-implants will be analyzed regarding their mechanical properties, chemical composition, microstructure and dimensional accuracy, as well as concerning their biological behaviour. The chemical and cellular mediated solubility and the osteogenic potential will be evaluated in vitro by using human osteoblastic and human osteoclastic cells. These results will be validated in vivo in a rabbit model. Therefore, the structures will be implanted either in a non-load-bearing defect (drilled hole, femoral condyle) or in a segmental load-bearing defect (proximal tibia) followed by the investigation of the degradation rate and healing of the defect area. The bone-implant network will be analyzed in vivo by X-ray- and in-vivo-µCT over a course of up to 44 weeks, as well as ex vivo by immunohistological and microscopic analyses. Finally, the medical potential of the developed bone implant for application in human or veterinary medicine will be verified in an individualized treatment of veterinary patients.
DFG Programme
Research Grants
