Electroformed iron as new biomaterial for degradable stents: development process and structure-properties relationship.
An electroforming technique was developed for fabricating iron foils targeted for application as biodegradable cardiovascular stent material. The microstructure, mechanical properties and corrosion of electroformed iron (E-Fe) foils were evaluated and compared with those of pure iron made by casting and thermomechanical treatment (CTT-Fe), with 316L stainless steel (316L SS) and with other candidate metallic materials for biodegradable stents. Electron backscattered diffraction revealed an average grain size of 4 microm for E-Fe, resulting in a high yield (360 MPa) and ultimate tensile strength (423 MPa) being superior to those of other metallic biodegradable stent materials. Annealing at 550 degrees C was found to improve the ductility of the E-Fe from 8% to 18%. The corrosion rate of E-Fe in Hanks' solution, measured by potentiodynamic polarization, was higher than that of CTT-Fe, which had been found to have a slow in vivo degradation. The results showed that E-Fe possesses fine-grain microstructure, suitable mechanical properties and moderate corrosion rate as a degradable stent material.
Moravej
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Laboratory for Biomaterials and Bioengineering, Department of Mining, Metallurgical and Materials Engineering & University Hospital Research Center, Université Laval, Québec City, QC, Canada.
Prima
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Fiset
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Mantovani
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D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000737:chemistry*; D003343:Corrosion; D004563:Electrochemistry / Q000379:methods*; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D015607:Stents; D013329:Structure-Activity Relationship; D013718:Tensile Strength; D014961:X-Ray Diffraction
D001672:Biocompatible Materials; D007501:Iron