Iron-Based Degradable Implants

Loffredo, Sergio; Paternoster, Carlo

doi:10.1016/b978-0-12-801238-3.11023-2

Cited by 7 publications

(10 citation statements)

References 8 publications

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Section: Biodegradability Of Pure Ironmentioning

confidence: 99%

“…Biocompatibility on the cellular level requires that the presence of the biomaterial is not toxic for building the artery wall with endothelial cells and cells in the blood [ 49 ]. For this reason, endothelial cells, blood cells, or smooth muscle cells (SMC) are used as the basis for cytotoxicity stent material studies [ 25 ].…”

Section: Biological Properties Of Iron-based Materialsmentioning

confidence: 99%

“…When the barrier formation is complete, the implant functions in a different environment than before. This may be the main reason for the differences in long-term in vivo and in vitro corrosion [25]. (4) Dissolved oxygen: Blood has about 3 cm 3 /dm 3 of dissolved oxygen, (4.3 mg/dm 3 ) while, for example, most solutions used in cell-based tests (Hank's solution) have almost twice the level of dissolved oxygen-about 8 mg/dm 3 .…”

Section: Biodegradability Of Pure Ironmentioning

confidence: 99%

“…Iron has a high strength, ductility, and formability ( Table 1 ), allowing stents with thinner constructions and struts or fabrication of special shapes, like foils or foams [ 25 ]. Unfortunately, in comparison to Zn and Mg, iron has a corrosion rate so low that pure iron can hardly be called “biodegradable”.…”

Section: Introductionmentioning

confidence: 99%

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Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

2021

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Iron, while attracting less attention than magnesium and zinc, is still one of the best candidates for biodegradable metal stents thanks its biocompatibility, great elastic moduli and high strength. Due to the low corrosion rate, and thus slow biodegradation, iron stents have still not been put into use. While these problems have still not been fully resolved, many studies have been published that propose different approaches to the issues. This brief overview report summarises the latest developments in the field of biodegradable iron-based stents and presents some techniques that can accelerate their biocorrosion rate. Basic data related to iron metabolism and its biocompatibility, the mechanism of the corrosion process, as well as a critical look at the rate of degradation of iron-based systems obtained by several different methods are included. All this illustrates as the title says, what was done within the topic of biodegradable iron-based materials and what more can be done.

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Section: Biodegradability Of Pure Ironmentioning

confidence: 99%

Section: Biological Properties Of Iron-based Materialsmentioning

confidence: 99%

Section: Biodegradability Of Pure Ironmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

2021

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“…One of the current major issues in testing of Fe-based biodegradable alloys is poor data correlation between in vitro and in vivo studies. Several factors contribute to this issue, such as necessary setup simplifications, 43,44 solutions that do not fully reproduce whole blood, 25,28,45 and reduced test duration. 46 Most studies that limited immersion times below 28 days did not report phosphate formation, 14,16,47,48 while other studies did but only after at least 28 days of immersion.…”

Section: Discussionmentioning

confidence: 99%

Six-Month Long In Vitro Degradation Tests of Biodegradable Twinning-Induced Plasticity Steels Alloyed with Ag for Stent Applications

Loffredo

Gambaro

Andrade

et al. 2021

ACS Biomater. Sci. Eng.

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Twinning-induced plasticity (TWIP) Fe–Mn–C steels are biodegradable metals with far superior mechanical properties to any biodegradable metal, including Mg alloys, used in commercially available devices. For this reason, the use of Fe–Mn–C alloys to produce thinner and thinner implants can be exploited for overcoming the device size limitations that biodegradable stents still present. However, Fe–Mn steels are known to form a phosphate layer on their surface over long implantation times in animals, preventing device degradation in the required timeframe. The introduction of second phases in such alloys to promote galvanic coupling showed a short-term promise, and particularly the use of Ag looked especially effective. Nonetheless, the evolution of the corrosion mechanism of quaternary Fe–Mn–C–Ag alloys over time is still unknown. This study aims at understanding how corrosion changes over time for a TWIP steel alloyed with Ag using a simple static immersion setup. The presence of Ag promoted some galvanic coupling just in the first week of immersion; this effect was then suppressed by the formation of a mixed carbonate/hydroxide layer. This layer partly detached after 2 months and was replaced by a stable phosphate layer, over which a new carbonate/hydroxide formed after 4 months, effectively hindering the sample degradation. Attachment of phosphates to the surface matches 1-year outcomes from animal tests reported by other authors, but this phenomenon cannot be predicted using immersion up to 28 days. These results demonstrate that immersion tests of Fe-based degradable alloys can be related to animal tests only when they are carried out for a sufficiently long time and that galvanic coupling with Ag is not a viable strategy in the long term. Future works should focus more on surface modifications to control the interfacial behavior rather than alloying in the bulk.

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Enhancing the degradation rate and biomineralization nature of antiferromagnetic Fe‐20Mn alloy by groove pressing

Sahu,

Sampath Kumar,

Chakkingal

et al. 2024

J Biomedical Materials Res

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The Fe‐Mn alloys are potential candidates for biodegradable implant applications. However, the very low degradation rates of Fe‐Mn alloys in the physiological environment are a major disadvantage. In this study, the degradation rate of a Fe‐20Mn alloy was improved using the groove pressing (GP) technique. Hot rolled sheets of 2 mm thickness were subjected to GP operation at 1000°C. Uniform fine‐grained (UFG) Fe‐Mn alloys were obtained using the GP technique. The influence of GP on the microstructure, mechanical properties, degradation behavior in simulated body fluid (SBF), surface wettability, biomineralization, and cytocompatibility was investigated and compared to the annealed (A Fe‐Mn) and rolled (R Fe‐Mn) sample. The groove‐pressed Fe‐Mn (G Fe‐Mn) alloy had a grain size of approximately 40 ± 16 μm whereas the A Fe‐Mn and R Fe‐Mn samples had grain sizes of 303 ± 81 and 117 ± 14.5 μm, respectively. Enhanced strength and elongation were also observed with the G Fe‐Mn sample. The potentiodynamic polarization test showed the highest Icorr, lowest polarization resistance, and lowest Ecorr for the G Fe‐Mn sample among all other samples indicating its higher degradation rate. The weight loss data from immersion tests also shows that the percentage of weight loss increases with time indicating the accelerated degradation behavior of the sample. The static immersion test showed an enhancement in weight loss of 0.46 ± 0.02% and 1.02 ± 0.05% for R Fe‐Mn and G Fe‐Mn samples, respectively, than A Fe‐Mn sample (0.31 ± 0.03%) after 56 days in immersion in SBF. The greater biomineralization tendency in UFG materials is confirmed by the G Fe‐Mn sample's stronger hydroxyapatite deposition. When compared to the A Fe‐Mn and R Fe‐Mn samples, the G Fe‐Mn sample has a better wettability, which promotes higher cell adhesion and vitality, showing higher biocompatibility. This study demonstrates that Fe‐20Mn processed by GP has potential applications for the manufacture of biodegradable metallic implants.

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Iron-Based Degradable Implants

Cited by 7 publications

References 8 publications

Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

Six-Month Long In Vitro Degradation Tests of Biodegradable Twinning-Induced Plasticity Steels Alloyed with Ag for Stent Applications

Enhancing the degradation rate and biomineralization nature of antiferromagnetic Fe‐20Mn alloy by groove pressing

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