Biodegradable behaviors of AZ31 magnesium alloy in simulated body fluid

Song, Yingwei; Shan, Dayong; Chen, Rongshi; Zhang, Fan; Han, En‐Hou

doi:10.1016/j.msec.2008.08.026

Cited by 356 publications

(156 citation statements)

References 15 publications

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“…At first, corrosion of Mg alloy surface enables a series of reactions within the physiological environment leading to the formation of the amorphous Mg and O-rich compound, Mg(OH) 2 , as supported by the elemental analysis of region I. Indeed, previous reports observed similar formation of Mg(OH) 2 precipitates around the degrading Mg surfaces (25,26). With the experimental evidences, Mg-Ca-Zn alloy degradation and formation of by-product can be described from the thermodynamic point of view.…”

Section: Discussionmentioning

confidence: 59%

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

Lee

Han

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

369

236

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There has been a tremendous amount of research in the past decade to optimize the mechanical properties and degradation behavior of the biodegradable Mg alloy for orthopedic implant. Despite the feasibility of degrading implant, the lack of fundamental understanding about biocompatibility and underlying bone formation mechanism is currently limiting the use in clinical applications. Herein, we report the result of long-term clinical study and systematic investigation of bone formation mechanism of the biodegradable Mg-5wt%Ca-1wt%Zn alloy implant through simultaneous observation of changes in element composition and crystallinity within degrading interface at hierarchical levels. Controlled degradation of Mg-5wt%Ca-1wt%Zn alloy results in the formation of biomimicking calcification matrix at the degrading interface to initiate the bone formation process. This process facilitates early bone healing and allows the complete replacement of biodegradable Mg implant by the new bone within 1 y of implantation, as demonstrated in 53 cases of successful long-term clinical study.biodegradable implant | bone formation | clinical application T he century-old concept of the fixation device that holds the fractured bones in place to allow repair through the natural bone remodeling process is still being practiced today without alteration (1-5). The recent rapid growth of the elderly demographic of physically active adults has tremendously intensified the occurrence of bone trauma cases, highlighting once again the major drawbacks of current surgical approaches and osteosynthesis systems, such as inevitable secondary surgery to remove the inert fixation devices after complete bone healing and inflammatory response due to the release of metal ions. In the past decade, countless studies have been performed to control and optimize the mechanical and corrosion properties of magnesium-based alloys (6-9), which, thanks to their degradation in the physiological environment, could overcome the limitations of inert implant materials and shift the paradigm of conventional bone fixation devices toward new horizons. Driven by these new possibilities, important findings regarding, among others, the degradation mechanism of Mg-based alloys (10, 11), the formation of corrosion protective layers by degradation products (12, 13), and the osteogenetic properties of Mg ions (14, 15) have been reported in the literature. However, such findings are based on the observation of degradation products and of bone healing at the macroscale level. Due to lack of fundamental understanding on biocompatibility and underlying bone formation mechanism of the degradation product, there is so far only one known case of statistically insignificant clinical study result (16) with a short-term follow-up. In our previous study, we reported successful development and long-term in vivo study of uniformly slowly degrading Mg-5wt%Ca-1wt%Zn alloy system (SI Appendix, Figs. S1 and S2) featuring adequate mechanical strength [ultimate tensile strength (UTS) ∼250 MPa] (17) a...

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Section: Discussionmentioning

confidence: 59%

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

Lee

Han

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

369

236

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“…After Pyo and Reynolds [61] As an example, the electrochemical reactions in the magnesium anode and a PPy cathode are shown below. The anode reactions involve the oxidation of Mg metal to Mg 2þ ions together with hydrogen gas evolution [63]:…”

Section: Drug Deliverymentioning

confidence: 99%

Electrodeposited conductive polymers for controlled drug release: polypyrrole

Alshammary

Walsh

Herrasti

et al. 2015

J Solid State Electrochem

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Over the last 40 years, electrically conductive polymers have become well established as important electrode materials. Polyanilines, polythiophenes and polypyrroles have received particular attention due to their ease of synthesis, chemical stability, mechanical robustness and the ability to tailor their properties. Electrochemical synthesis of these materials as films have proved to be a robust and simple way to realise surface layers with controlled thickness, electrical conductivity and ion transport. In the last decade, the biomedical compatibility of electrodeposited polymers has become recognised; in particular, polypyrroles have been studied extensively and can provide an effective route to pharmaceutical drug release. The factors controlling the electrodeposition of this polymer from practical electrolytes are considered in this review including electrolyte composition and operating conditions such as the temperature and electrode potential. Voltammetry and current-time behaviour are seen to be effective techniques for film characterisation during and after their formation. The degree of take-up and the rate of drug release depend greatly on the structure, composition and oxidation state of the polymer film. Specialised aspects are considered, including galvanic cells with a Mg anode, use of catalytic nanomotors or implantable biofuel cells for a self-powered drug delivery system and nanoporous surfaces and nanostructures. Following a survey of polymer and drug types, progress in this field is summarised and aspects requiring further research are highlighted.

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“…The PO 3− 4 in SBF will bond with Ca 2+ and Mg 2+ to form the compound of hydroxyapatite and magnesium phosphate [32]. The undissolved Mg(OH) 2 film on the surface of Mg alloy was considered to provide beneficial sites for hydroxyapatite nucleation [31].…”

Section: Discussionmentioning

confidence: 99%

Microstructure Evolution and Biodegradation Behavior of Laser Rapid Solidified Mg–Al–Zn Alloy

Bin

et al. 2017

Metals

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Abstract:The too fast degradation of magnesium (Mg) alloys is a major impediment hindering their orthopedic application, despite their superior mechanical properties and favorable biocompatibility. In this study, the degradation resistance of AZ61 (Al 6 wt. %, Zn 1 wt. %, remaining Mg) was enhanced by rapid solidification via selective laser melting (SLM). The results indicated that an increase of the laser power was beneficial for enhancing degradation resistance and microhardness due to the increase of relative density and formation of uniformed equiaxed grains. However, too high a laser power led to the increase of mass loss and decrease of microhardness due to coarsened equiaxed grains and a reduced solid solution of Al in the Mg matrix. In addition, immersion tests showed that the apatite increased with the increase of immersion time, which indicated that SLMed AZ61 possessed good bioactivity.

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Biodegradable behaviors of AZ31 magnesium alloy in simulated body fluid

Cited by 356 publications

References 15 publications

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

Electrodeposited conductive polymers for controlled drug release: polypyrrole

Microstructure Evolution and Biodegradation Behavior of Laser Rapid Solidified Mg–Al–Zn Alloy

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