Dr. Mariana Calin

Abstract:

Nowadays, magnetic resonance imaging (MRI) has become a powerful diagnostic tool in medical fields, e.g. in brain surgery, cardiovascular diseases and orthopedics. However, MRI diagnosis is inhibited by the presence of certain metallic implants in the body because they become magnetized in the intense magnetic field of the MRI instrument, which may produce image artifacts and therefore prevent exact diagnosis. To decrease the artifacts, medical alloys/devices with low magnetic susceptibility are required. Compared with stainless steel and Co–Cr alloys, which are conventional implant alloys, titanium (Ti)– and zirconium (Zr)-based alloys have lower magnetic susceptibility and are more suitable for clinical investigation using MRI than the others [1]

Metallic glasses have a great potential for small medical devices useful in dentistry (e.g. dental implants and suprastructures), osteosynthesis (e.g fracture fixation systems) and occlusive vascular diseases (e.g stents and aneurysm clips) [2-4]. Ti-, Zr- and precious metal-based bulk metallic glassess (BMGs) have been widely investigated as potential biomaterials especially for bone-related implant applications [2-3]. However, the major problem still facing the development of biomedical metallic glasses is the one of inducing amorphization without using any harmful alloying additions. We reviewed the biological safety and glass forming tendency in Ti of a series of alloying elements [2].

In the present paper we discuss the underlying processes for amorphous phase formation, mechanical and biochemical behavior as well as the biocompatibility of various Ni-free Ti- and Zr-based BMGs with potential for biomedicine. Moreover, we report the formation novel amorphous Ti-Zr-Nb-Hf-Si multi-principal element alloys with excellent corrosion stability in simulated body fluids and ultralow magnetic susceptibility, less than one-third of that of commercial biomedical Ti-based materials [4]. These alloys exhibit also higher X-ray linear attenuation coefficients relevant for interventional X-ray-based medical imaging. This two-fold advantage (lower magnetic susceptibility and higher radiopacity) allows the materials to be more precisely visualized via biomedical imaging methods, which is especially important for miniaturised implants.

Financial support through the European Commission (H2020-MSCA-ITN BIOREMIA GA 861046) is gratefully acknowledged.