Smart implantable devices
Degradable Mg-based implants open up new possibilities in orthopeadic and trauma surgery but also for cardiovascular interventions or the treatment of cancer or infections. Key is the close coupling between the released ions from the metal which are influencing the biological processes not only in the cell at the surface of the implant but also triggers the immune system. This in turn changes the degradation processes of the material. To optimize the tissue regeneration, the material degradation must be adopted to the biological requirement of the individual location and patient pathology. Digital twins along the life cycle of the implant will help to accelerate the development by explicitly utilizing biological and patient date.
The implant can stimulate cellular reactions not only by biochemically but also by curvature, surface chemistry, stiffness or other mechanical stimuli. For Mg-based implants cell can also influence the material degradation by production of proteins or extracellular matrix (adapted from [ Shchukarev, A., M. Ransjö, and Ž. Mladenović. To Build or Not to Build: The Interface of Bone Graft Substitute Materials in Biological Media from the View Point of the Cells. 2011.])
Our technological capabilities for systematically adjusting the properties of polymer materials make them ideal candidates for a whole range of implants, particularly in soft tissue. Depending on the task, polymers can be designed for structural, often permanent functions, as well as for transient applications with hydrolytic or enzymatic degradation options. The availability of numerous well-established processing methods contributes to their versatility. The formation of interfaces between polymer implants and tissue/blood depends on chemical and physical properties of the materials as well as the potential biologisation strategies applied (proteins, cells), addressing both regenerative stimuli and implant integration. One example is a polymer-onlyatrial occluder with improved functionality.
Atrial fibrillation is a leading cause of stroke, with clots mostly originating at the left atrial appendage (LAA). A prominent treatment option are occluders (LAAO; see (a)). Current metal-based LAAO designs suffer from numerous drawbacks (leakage, tissue damage…). Polymers (b; here P(LLA-co-CL)/PDLA ) can be used for novel LAAOs; with a mock-implantation in a 3D-printed, patient-specific appendage shape shown in (c). Such novel designs require iterative rounds of optimization via computational design strategies and demonstrator fabrication (d),, which in the future will also include sensors placed at the device/tissue-interface (arrows in (a)) to monitor both implant performance and patient parameters, also providing part of the data basis flowing into models of the device in its intended system context.
Contact
Regine Willumeit-Römer
Helmholtz-Zentrum Geesthacht
E-Mail
