Biodegradable / absorbable FeMn-based alloys for implant applications

Contact: Prof. Dr. Julia Hufenbach

The interest in biodegradable metallic materials for the application as temporary implants has been continuously increasing within the last years. Due to the progressive degradation after providing a temporary support on healing process of a diseased tissue, disadvantages of permanent implants, such as revision surgery, lacking adaption to growth or chronic inflammation, may overcome.

Due to the broad adjustable range of mechanical properties, the excellent processability and the high mechanical integrity during degradation FeMn-based alloys are of great interest for (cardio)vascular or urological stent applications. Especially twinning induced plasticity (TWIP) alloys, as e.g. Fe-30Mn-1C-0.25S, are attractive candidates due to their high strength and ductility under tensile load, and moderate corrosion rate, as shown in previous studies [1-4]. Owing to the excellent mechanical properties, such TWIP alloys show a high potential for the realization of very thin stent structures. Furthermore, in first in vitro cell culture tests a promising biocompatibility was observed.

The aim of these research activities is the development of novel FeMn-based alloys in combination with tailored preparation processes. Hereby, e.g. special casting technologies or selective laser melting (SLM) - as additive manufacturing technique - are applied for tailoring the microstructure and related mechanical, chemical and biological properties.

Funding of this project by the DFG under project number HU 2371/1-1 is gratefully acknowledged.

Electron backscatter diffraction mapping of a cast FeMnCS alloy and a SLM-processed counterpart perpendicular to building direction (BD) [1].

Engineering tensile stress-strain curves of SLM-processed and cast FeMnCS [1]; Confocal laser scanning microscopy image of endothelial cells on FeMnCS stent structure after one day of cultivation (green: cytoskeleton, blue: nucleus, red: membrane protein).

Biodegradable stent structures processed by SLM as well as FeMnCS stent crimped over a balloon catheter before and after expansion.

Selected publications:

[1] J. Hufenbach, J. Sander, F. Kochta, S. Pilz, A. Voß, U. Kühn, A. Gebert: Effect of Selective Laser Melting on Microstructure, Mechanical, and Corrosion Properties of Biodegradable FeMnCS for Implant Applications, Advanced Engineering Materials (2020) 2000182.

[2] J. Hufenbach, F. Kochta, H. Wendrock, A. Voß, L. Giebeler, S. Oswald, S. Pilz, U. Kühn, A. Lode, M. Gelinsky, A. Gebert: S and B microalloying of biodegradable Fe-30Mn-1C - Effects on microstructure, tensile properties, in vitro degradation and cytotoxicity, Materials and Design 142 (2018) 22-35.

[3] A. Gebert, F. Kochta, A. Voß, S. Oswald, M. Fernandez-Barcia, U. Kühn, J. Hufenbach: Corrosion studies on Fe-30Mn-1C alloy in chloride-containing solutions with view to biomedical application, Materials and Corrosion 69 (2018) 167-177.

[4] J. Hufenbach, H. Wendrock, F. Kochta, U. Kühn, A. Gebert: Novel biodegradable Fe-Mn-C-S alloy with superior mechanical and corrosion properties, Materials Letters 186 (2017) 330-333.