The Manufacture of Resorbable Suture Material from Magnesium

Abstract

Magnesium alloys present an alternative to medical cases in which polymeric sutures may not be ideal. To date, no efficient and low‐cost manufacturing process for the fabrication of magnesium‐based sutures can be found. To obtain an alternative, the previously characterised magnesium alloys ZEK100 (98% Mg), AX30 (96.2% Mg), AL36 (91% Mg) and MgCa0.8 (99.2% Mg) were cast, extruded into 30 mm diameter bars and extruded into 0.5 mm diameter wires. To determine the mechanical properties of the wires, grain size measurements, tensile tests as well as qualitative bending tests were carried out. The ZEK100 alloy's wires showed the finest microstructure having grains of 1.2 µm in diameter. Coarser microstructures were observed for MgCa0.8, AX30 and AL36. The alloy ZEK100 had the highest tensile stress (367 MPa) also revealing a brittle behaviour due to its fine microstructure. The tensile test, carried out for AX30 as well as AL36, resulted in comparable high fracture strains (10.6%) and tensile stresses (300 MPa). However, MgCa0.8 showed a tensile strength of 315 MPa and a low strain of 1.6%. Within the qualitative bending test wires made of the alloy AL36 were able to form tight knots, which is a key feature for suture applications. The comparison of the magnesium sutures with commercially available polymeric sutures revealed lower strength and elongation for the magnesium alloys. Yet, the wires exhibited mechanical properties that can meet the requirements of a suture material.

Biodegradable Metallic Wires in Dental and Orthopedic Applications: A Review

“…Seitz et al [125,126] were the first researchers produced Mg wires for suture applications. They selected four Mg alloys, ZEK100, MgCa0.8, AL36 and AX30, which were previously reported to be biocompatible.…”

“…They selected four Mg alloys, ZEK100, MgCa0.8, AL36 and AX30, which were previously reported to be biocompatible. Mg suture wires of 0.3 to 0.5 mm in diameter were fabricated by hot extrusion [125] and their diameter was further decreased via multiple drawing [126]. Despite low mechanical properties of the extruded wires, they could meet the parameters required for a surgical suture.…”

Recent Advances in Biodegradable Metals for Medical Sutures: A Critical Review

“…[ 3,[43][44][45] They may also exhibit more favorable degradation behavior than polymers. [ 3,[43][44][45] This Review compares the mechanical, corrosion, and biocompatibility properties of degradable polymers and metals (Mg, Fe, Zn) in the context of surgical applications to close a wound or join tissues. Different environments and application sites have an impact on the degradation behavior of materials and are therefore discussed within this contribution.…”

Biocompatible Magnesium Alloys as Degradable Implant Materials - Machining Induced Surface and Subsurface Properties and Implant Performance

“…Therefore, the influence of machining processes with different chipping and non-chipping techniques and process kinematics on resulting surface and subsurface properties is analyzed and correlations with the in-vitro corrosion kinetics for different magnesium alloys are developed. All experiments described are carried out on alloys, which were developed for biomedical applications and provided as extruded profiles by the Institute of Material Science (IW) of the Leibniz Universität Hannover (Seitz et al, 2010). Subsequent in-vitro investigations of specifically modified workpieces provide information on the influence of different subsurface conditions on the degradation behavior.…”