Zn-Li alloy after extrusion and drawing: Structural, mechanical characterization, and biodegradation in abdominal aorta of rat

Zhao, Shuai; Seitz, Jan‐Marten; Eifler, Rainer; Maier, Hans Jürgen; Guillory, Roger J.; Earley, Elisha J.; Drelich, Adam J.; Goldman, Jeremy; Drelich, Jaroslaw

doi:10.1016/j.msec.2017.02.167

Cited by 193 publications

(111 citation statements)

References 47 publications

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“…An electrochemical analysis of Zn wires corroded in vitro supports this interpretation (Supplemental Section). The present findings are consistent with our earlier analyses [38,40]. Longer residence of Zn wires in vivo was also qualitatively proven to lead to more production of corrosion products, which are more evenly distributed around the metallic wire.…”

Section: Resultssupporting

confidence: 93%

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Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate

et al. 2017

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Metallic zinc implanted into the abdominal aorta of rats out to 6 months has been demonstrated to degrade while avoiding responses commonly associated with the restenosis of vascular implants. However, major questions remain regarding whether a zinc implant would ultimately passivate through the production of stable corrosion products or via a cell mediated fibrous encapsulation process that prevents the diffusion of critical reactants and products at the metal surface. Here, we have conducted clinically relevant long term in vivo studies in order to characterize late stage zinc implant biocorrosion behavior and products to address these critical questions. We found that zinc wires implanted in the murine artery exhibit steady corrosion without local toxicity for up to at least 20 months post-implantation, despite a steady buildup of passivating corrosion products and intense fibrous encapsulation of the wire. Although fibrous encapsulation was not able to prevent continued implant corrosion, it may be related to the reduced chronic inflammation observed between 10 and 20 months post-implantation. X-ray elemental and infrared spectroscopy analyses confirmed zinc oxide, zinc carbonate, and zinc phosphate as the main components of corrosion products surrounding the Zn implant. These products coincide with stable phases concluded from Pourbaix diagrams of a physiological solution and in vitro electrochemical impedance tests. The results support earlier predictions that zinc stents could become successfully bio-integrated into the arterial environment and safely degrade within a time frame of approximately 1 – 2 years.

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Section: Resultssupporting

confidence: 93%

“…The concentrations for HPO 4 2− and HCO 3 − (CO 2 (aq)) in this diagram were set to be identical to the values in human blood plasma (0.001 mol/L for HPO 4 2− , and 0.027 mol/L for CO 2 (aq)) [53]. The orange circles marked on the Pourbaix diagrams represent physiological conditions of tissue fluid (pH ≈ 7.4 and E ≈ 0.78 V) [40,60]. …”

Section: Resultsmentioning

confidence: 99%

Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate

et al. 2017

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“…Moreover, the degradation rate of zinc alloys containing these elements should match the tolerance or effective dose range of these elements in the human body. Zhao et al [25,56] investigated the effect of Li as a zinc alloying element. They reported the overall quantities of lithium released from a zinc-lithium implant (with 0.7 wt % of Li) at two orders of magnitude below the daily bodily consumption allowances.…”

Section: Zinc Alloysmentioning

confidence: 99%

The Prospects of Zinc as a Structural Material for Biodegradable Implants—A Review Paper

Levy

Goldman

Aghion

2017

Metals

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Abstract:In the last decade, iron and magnesium, both pure and alloyed, have been extensively studied as potential biodegradable metals for medical applications. However, broad experience with these material systems has uncovered critical limitations in terms of their suitability for clinical applications. Recently, zinc and zinc-based alloys have been proposed as new additions to the list of degradable metals and as promising alternatives to magnesium and iron. The main byproduct of zinc metal corrosion, Zn 2+ , is highly regulated within physiological systems and plays a critical role in numerous fundamental cellular processes. Zn 2+ released from an implant may suppress harmful smooth muscle cells and restenosis in arteries, while stimulating beneficial osteogenesis in bone. An important limitation of pure zinc as a potential biodegradable structural support, however, lies in its low strength (σ UTS~3 0 MPa) and plasticity (ε < 0.25%) that are insufficient for most medical device applications. Developing high strength and ductility zinc with sufficient hardness, while retaining its biocompatibility, is one of the main goals of metallurgical engineering. This paper will review and compare the biocompatibility, corrosion behavior and mechanical properties of pure zinc, as well as currently researched zinc alloys.

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“…18 More recently, a number of studies were published suggesting zinc-magnesium, zinc-aluminum (Al), zinc-lithium (Li) and zinc-silver (Ag) as potential biodegradable alloys. [19][20][21][22] The zinc-silver alloy was shown to possess high mechanical strength as well as superplasticity. 22 Current knowledge suggests zinc alloys to be a promising new class of biodegradable metals.…”

Section: Introductionmentioning

confidence: 99%

Zn-Mg and Zn-Ag Degradation Mechanism Under Biologically Relevant Conditions

Törne

Khan

Örnberg

et al. 2017

Surface Innovations

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Zinc (Zn) alloys form a promising new class of biodegradable metals that combine suitable mechanical properties with the favorable degradation properties of pure zinc. However, the current understanding of the influence of alloying elements on the corrosion of zinc alloys, in biologically relevant media, is limited. The authors studied the degradation of three alloys, zinc-4 wt% silver (Ag), zinc-0·5 wt% magnesium (Mg) and zinc-3 wt% magnesium by in situ electrochemical impedance spectroscopy (EIS). After exposure for 1 h or 30 d, the samples were characterized by infrared spectroscopy and scanning electron microscopy. The presence of secondary phases in the alloy microstructure induced selective corrosion and increased the degradation rate. EIS analysis revealed an increase in surface inhomogeneity already at short (hours) immersion times. The microgalvanic corrosion of the zinc-silver alloy resulted in enrichment of the AgZn 3 phase at the sample surface. The enrichment of silver and potential release of AgZn 3 particles may result in complications during the tissue regeneration. The zinc-magnesium alloy surface was depleted of the magnesium-rich phase after 8-12 d. The selective dissolution caused local precipitation of corrosion products and a thicker corrosion layer with larger pore size consistent with increased corrosion rate.

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Zn-Li alloy after extrusion and drawing: Structural, mechanical characterization, and biodegradation in abdominal aorta of rat

Cited by 193 publications

References 47 publications

Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate

Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate

The Prospects of Zinc as a Structural Material for Biodegradable Implants—A Review Paper

Zn-Mg and Zn-Ag Degradation Mechanism Under Biologically Relevant Conditions

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