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Radiopaque FeMnN-Mo composite drawn filled tubing wires for braided absorbable neurovascular devices

Authors :
Adam J. Griebel
Petra Maier
Henry Summers
Benjamin Clausius
Isabella Kanasty
Weilue He
Nicholas Peterson
Carolyn Czerniak
Alexander A. Oliver
David F. Kallmes
Ramanathan Kadirvel
Jeremy E. Schaffer
Roger J. Guillory, II
Source :
Bioactive Materials, Vol 40, Iss , Pp 74-87 (2024)
Publication Year :
2024
Publisher :
KeAi Communications Co., Ltd., 2024.

Abstract

Flow diverter devices are small stents used to divert blood flow away from aneurysms in the brain, stagnating flow and inducing intra-aneurysmal thrombosis which in time will prevent aneurysm rupture. Current devices are formed from thin (∼25 μm) wires which will remain in place long after the aneurysm has been mitigated. As their continued presence could lead to secondary complications, an absorbable flow diverter which dissolves into the body after aneurysm occlusion is desirable. The absorbable metals investigated to date struggle to achieve the necessary combination of strength, elasticity, corrosion rate, fragmentation resistance, radiopacity, and biocompatibility. This work proposes and investigates a new composite wire concept combining absorbable iron alloy (FeMnN) shells with one or more pure molybdenum (Mo) cores. Various wire configurations are produced and drawn to 25–250 μm wires. Tensile testing revealed high and tunable mechanical properties on par with existing flow diverter materials. In vitro degradation testing of 100 μm wire in DMEM to 7 days indicated progressive corrosion and cracking of the FeMnN shell but not of the Mo, confirming the cathodic protection of the Mo by the FeMnN and thus mitigation of premature fragmentation risk. In vivo implantation and subsequent μCT of the same wires in mouse aortas to 6 months showed meaningful corrosion had begun in the FeMnN shell but not yet in the Mo filament cores. In total, these results indicate that these composites may offer an ideal combination of properties for absorbable flow diverters.

Details

Language :
English
ISSN :
2452199X
Volume :
40
Issue :
74-87
Database :
Directory of Open Access Journals
Journal :
Bioactive Materials
Publication Type :
Academic Journal
Accession number :
edsdoj.49ed5649e54d62bb578d85ba7c5235
Document Type :
article
Full Text :
https://doi.org/10.1016/j.bioactmat.2024.06.002