Search Results (206)

Biodegradable magnesium alloys have emerged as promising alternatives to permanent metallic implants due to their unique combination of mechanical compatibility with bone and complete resorption, addressing the persistent issues of stress shielding and secondary removal surgeries. This review critically examines the historical development of magnesium-based biomaterials, highlighting advances in alloy design, manufacturing processes, and surface engineering that now enable tailored degradation and improved clinical performance. Drawing on recent clinical and preclinical studies, we summarize improvements in corrosion resistance, mechanical properties, and biocompatibility that have supported the clinical translation of magnesium alloys across a variety of orthopedic and emerging medical applications. However, challenges remain, including unpredictable in vivo degradation kinetics, limited long-term safety data, lack of standardized testing protocols, and ongoing regulatory uncertainties. We conclude that while magnesium-based biomaterials have advanced from experimental concepts to clinically validated solutions, further progress in personalized degradation control, real-time monitoring, and harmonized regulatory frameworks is needed to fully realize their transformative clinical potential. Full article

Background and Objectives: Magnesium (Mg)-based materials, such as the WE43 alloy, show potential in biomedical applications owing to their advantageous mechanical properties and biodegradability; however, their quick corrosion rate and hydrogen release restrict their general clinical utilization. This study aimed to develop a novel Mg-Zn-Ca alloy system based on WE43 alloy, evaluating the influence of Zn and Ca additions on microstructure, mechanical properties, cytocompatibility, and electrochemical behavior for potential use in biodegradable orthopedic applications. Materials and Methods: The WE43-Zn-Ca alloy system was developed by alloying standard WE43 (Mg–Y–Zr–RE) with 1.5% Zn and Ca concentrations of 0.2% (WE43_0.2Ca alloy) and 0.3% (WE43_0.3Ca alloy). Microstructural analysis was performed utilizing scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS), while the chemical composition was validated through optical emission spectroscopy and X-ray diffraction (XRD). Mechanical properties were assessed through tribological tests. Electrochemical corrosion behavior was evaluated using potentiodynamic polarization in a 3.5% NaCl solution. Cytocompatibility was assessed in vitro on MG63 cells using cell viability assays (MTT). Results: Alloys WE43_0.2Ca and WE43_0.3Ca exhibited refined, homogeneous microstructures with grain sizes between 70 and 100 µm, without significant structural defects. Mechanical testing indicated reduced stiffness and an elastic modulus similar to human bone (19.2–20.3 GPa), lowering the risk of stress shielding. Cytocompatibility tests confirmed non-cytotoxic behavior for alloys WE43_0.2Ca and WE43_0.3Ca, with increased cell viability and unaffected cellular morphology. Conclusions: The study validates the potential of Mg-Zn-Ca alloys (especially WE43_0.3Ca) as biodegradable biomaterials for orthopedic implants due to their favorable combination of mechanical properties, corrosion resistance, and cytocompatibility. The optimization of these alloys contributed to obtaining an improved microstructure with a reduced degradation rate and a non-cytotoxic in vitro outcome, which supports efficient bone tissue regeneration and its integration into the body for complex biomedical applications. Full article

Magnesium-based biomaterials have emerged as highly promising candidates in the realm of biomedical engineering due to certain unique properties. However, their widespread application has been limited by a number of challenges, such as insufficient mechanical strength and rapid degradation rates. This study sought to advance the development of high-performance magnesium alloys by examining the microstructural evolution and associated strengthening mechanisms of Mg-Zn alloys modified with varying Nd contents. Comprehensive characterization techniques—including optical microscopy, XRD, and SEM/EDS—were employed to explain the influence of Nd additions on the microstructures. Mechanical performance was assessed through hardness testing, the RFDA method for elastic modulus, and tensile testing. The microstructural analysis of the as-cast Mg-Zn-Nd alloys revealed a complex phase composition comprising dendritic α-Mg, Mg₄₁Nd₅, and a Mg₃Nd binary phase enriched with rare earth elements. Notably, increasing the Nd content from 0.5% to 5% by weight resulted in a significant enhancement of hardness, reaching 59 HV compared to 42 HV in the base alloy. The tensile strength increased significantly from 62.9 MPa in the Mg-2.5Zn-0.5Nd alloy to 186.8 MPa in the Mg-2.5Zn-5Nd alloy. The elastic modulus values across all investigated alloys remained consistently comparable, which is expected as the elastic modulus is primarily determined by atomic bonding and is not significantly affected by alloying additions. These findings underscore the potential of Nd-alloyed Mg-Zn systems as viable, mechanically robust alternatives for next-generation biodegradable orthopedic implants. Full article

This study presents the development and comprehensive evaluation of magnesium-based implants with surface modifications using selected polymers and bioactive compounds. The implants were fabricated via plasma electrolytic oxidation (PEO), followed by the application of chitosan, polydopamine (PDA), and gold nanoparticles as bioactive surface coatings. In vitro experiments, including FT-IR spectroscopy, scanning electron microscopy (SEM), wettability tests, biodegradation assays in simulated body fluid (SBF), electrochemical corrosion analysis, and cytotoxicity tests using MG-63 osteoblast-like cells, were employed to assess the physicochemical and biological properties of the materials. The PEO + PDA-modified samples demonstrated the highest corrosion resistance (−1.15 V corrosion potential), enhanced cell viability (~95%), and favorable surface wettability (contact angle ~12.5°), outperforming other tested configurations. These findings suggest that PEO combined with PDA offers a synergistic effect, leading to superior biocompatibility and degradation control compared to unmodified magnesium or single-coating strategies. The developed implants hold promise for orthopedic applications requiring biodegradable, bioactive, and cytocompatible materials. Full article

Biodegradable metallic implants represent a paradigm shift in implantology, eliminating secondary removal surgeries through predictable controlled degradation. This review systematizes current achievements in selective laser melting (SLM) of biodegradable metals (Mg, Fe, Zn), analyzing how processing parameters influence microstructure, mechanical properties, and degradation kinetics. Key findings demonstrate that SLM-produced Mg alloys achieve bone-matching modulus (40–45 GPa) with moderate degradation (1–3 mm/year); Fe-based systems provide superior strength (400–600 MPa) but slower degradation (0.1–0.5 mm/year); while Zn alloys offer intermediate properties. Design strategies for porous/lattice structures enhancing osseointegration and enabling property gradients are discussed. Major challenges include controlling degradation kinetics, optimizing SLM parameters for reactive metals, standardizing testing methodologies, and regulatory harmonization. This comprehensive analysis provides systematic guidelines for material selection and process optimization, establishing a foundation for developing next-generation personalized biodegradable implants. Full article

Biodegradable magnesium-based composites show potential application in orthopedic implants, with excellent biocompatibility, low density, and biodegradable characteristics inside the human body. In this study, the stir casting procedure was employed to produce magnesium–zinc MMCs (metal matrix composites) reinforced with MgO nanoparticles, and they were characterized intensively. The analyzed compositions were Mg/4Zn, Mg/4Zn/0.4MgO, and Mg/4Zn/0.6MgO. Their mechanical properties, corrosion resistance, and microstructure were then investigated employing tensile, impact, hardness, wear, and corrosion tests, supplemented with SEM analysis. The results indicate that the Mg-4Zn-0.6MgO composite exhibited the highest performance among the tested formulations, with a tensile strength of 150 MPa, a hardness of 65 HRE (Rockwell Hardness, E-scale), and enhanced corrosion resistance. These improvements are attributed to the uniform dispersion of MgO nanoparticles and the formation of a protective Mg(OH)₂ layer, which together contribute to mechanical reinforcement and controlled degradation behavior. The combination of superior mechanical properties and customizable biodegradability verifies the engineered Mg/4Zn/0.6MgO composite as a promising candidate for a biodegradable orthopedic fixation plate without secondary surgery. Full article

Magnesium as a biodegradable metal implant has garnered attention. Nevertheless, its rapid degradation rate and insufficient osseointegration restrict its clinical applications. In order to enhance the corrosion resistance and bioactivity of magnesium alloys, superhydrophobic hydroxyapatite (HA) layers were synthesized on micro-arc oxidized (MAO)-treated AZ31B magnesium alloy through liquid-phase deposition. This study examined the surface morphology, phase composition, bonding strength, wettability, electrochemical properties, and in vitro mineralization of the synthesized coatings. The study results demonstrated that the improved corrosion resistance of composite coatings in Hank’s solution is due to the formation of a protective HA layer. The inclusion of the MAO coating significantly enhances the bonding strength between the hydroxyapatite (HA) layer and the bare magnesium alloy. The concentration of NaH₂PO₄ affects both the microstructure and wettability. The composite coating exhibited excellent osseointegration capabilities, with new HA layers observed after immersing the samples in simulated body fluid (SBF) solution for three days. These findings suggest that the combination of MAO and solution treatment presents a promising method for enhancing biocompatibility and reducing magnesium degradation, thus making it a viable option for biodegradable implant applications. Full article

Magnesium-based coronary stents have gained significant interest due to their excellent biocompatibility, biodegradability, and mechanical properties. However, a key limitation of magnesium in biomedical applications is its low corrosion resistance, which compromises its structural integrity and mechanical strength over time. Polymeric coatings can overcome this challenge, enhancing magnesium-based implants’ corrosion resistance and overall performance. This study applied a polylactic acid (PLA) nanofiber coating to WE43 magnesium (Mg) stents via electrospinning to reduce their corrosion rate. Both uncoated and coated stents underwent in vitro immersion tests in Hank’s solution for 1, 3, 7, and 14 days. The effectiveness of the PLA coating was evaluated through morphological analysis, chemical composition assessment, corrosion behavior (weight change), magnesium ion release, and in vitro biocompatibility. The corrosion observed in the uncoated WE43 stents indicates that protective coatings are necessary to regulate degradation rates over extended implantation periods. The results demonstrated that coated stents exhibited improved performance, maintaining the integrity of the PLA coating for up to 14 days. The coated stents demonstrated reduced surface damage and lower weight loss resulting from lower magnesium release. In our study, the coated stents demonstrated a reduced corrosion rate (0.216 ± 0.013 mm/year) compared with the uncoated stents (0.312 ± 0.010 mm/year), both after 14 days. Additionally, in vitro biocompatibility results confirmed the non-toxic nature of PLA-coated stents, which enhances cellular proliferation and contributes to a more favorable environment for vascular healing. These findings suggest that PLA coatings can effectively prolong the functional durability of WE43 Mg stents, offering a promising solution for enhancing the performance of biodegradable stents in cardiovascular applications. Full article

Lightweight metals are increasingly used in biomedical engineering, and can be found in orthopaedics (screws, implants), stomatology, cardiology (stents) and as scaffolds. Magnesium alloys have a low density (1.74 g/cm³), which is very close to that of bone (1.75 g/cm³), as well as high biocompatibility, and are biodegradable. Unfortunately, their disadvantage is their low resistance to corrosion in the human body, which further causes deterioration of mechanical and physical properties. Improvement of these properties can be achieved by making the composite on a magnesium matrix—depending on the reinforcement added, the required properties can be obtained. This paper presents the results of a study on the extrusion of a magnesium matrix composite with titanium (Ti) reinforcement. The study included three-point bending tests, from which it is clear that the introduction of Ti reinforcement improves the bending strength of the specimens. In addition, the samples were immersed in SBF (simulated body fluid) for 1, 2, 4, 8, 12 and 24 h to determine the degradation of the Mg–Ti composite. Full article

This paper presents the biodegradation and cavitational erosion behavior of new zinc alloys in the ZnMgFe system. The alloys were heat-treated through homogenization at 300 °C and 400 °C, with maintenance times of 5 and 10 h each. The experimental research consisted of characterizing the structure and mechanical properties of the newly made alloys in different structural states, as well as determining their biodegradation and cavitation behavior. Biodegradability was achieved using laboratory tests in SBF, with different immersion durations (3, 7, 14, 21, or 35 days). The cavitation behavior was assessed by performing tests on a piezoceramic crystal vibrator in compliance with ASTM G32-2016, thus constructing the curves of the erosion velocity MDER(t) and the cumulative average erosion depth MDE(t). The analyses performed on the mechanical properties, microscopic images, and the cavitation parameters MDER and MDEmax (results at the end of the cavitation attack) showed the effect of the heat treatments on the structure and structural resistance to cyclic loadings of the cavitation. The double alloying of zinc with magnesium and iron may increase either the mechanical properties or the corrosion resistance to cavitation and can control the biodegradability of the resulting ZnMgFe alloy. The best heat treatment for improving these properties is homogenization at 400 °C/10 h, which may increase the cavitation erosion of zinc by up to seven times. The experimental results demonstrate that the new alloys from the ZnMgFe system are a good option for manufacturing biodegradable implants with functional in vitro properties. Full article

AZ31B magnesium alloy (wt.%: Al 2.94; Zn 0.87; Mn 0.57; Si 0.0112; Fe 0.0027; Cu 0.0008; Ni 0.0005; Mg remaining) has appropriate mechanical properties, good biodegradability and biocompatibility and can be used as a good orthopedic implant material. AZ31B magnesium alloy with a superhydrophobic surface exhibits excellent corrosion resistance and antibacterial adhesion performance, but superhydrophobic surfaces also hinder osteoblast adhesion and proliferation on the implants, resulting in unsatisfactory osteogenic properties. Therefore, it is necessary to achieve the wettability transition of the superhydrophobic surface at an early stage of implantation. In this work, superhydrophobic hydroxyapatite (HA)/calcium myristate (CaMS)/myristic acid (MA) composite coatings were prepared on AZ31B magnesium alloy using the hydrothermal and immersion methods. The composite coatings can spontaneously undergo the wettability transition from superhydrophobic to hydrophilic after complete exposure to simulated body fluid (SBF, a solution for modeling the composition and concentration of human plasma ions) for 9 h. The wettability transition mainly originated from the deposition and growth of the newly formed CaMS among the HA nanopillars during immersing, which deconstructed the micro-nano structure of the superhydrophobic coatings and directly exposed the HA to the water molecules, thereby significantly altering the wettability of the coatings. Benefiting from the superhydrophobic surface, the composite coating exhibited excellent antibacterial properties. After the wettability transition, the HA/CaMS/MA composite coating exhibited superior osteoblast adhesion performance. This work provides a strategy to enable a superhydrophobic coating to undergo spontaneous wettability transition in SBF, thereby endowing the coated magnesium alloy with a favorable osteogenic property. Full article

The WE43 magnesium alloy has gained attention in orthopedic implants due to its biodegradable properties, particularly for fabricating degradable fasteners. However, research on its hot-forming processes remains limited, primarily focusing on macroscopic finite element mechanical analyses. This study introduces a simplified high-temperature upsetting process and employs a mesoscale crystal plasticity finite element method to model the thermoforming behavior of WE43 fasteners for the first time. Comparative analyses with conventional finite element methods reveal that the crystal plasticity finite element method effectively captures the influence of microstructural evolution on macroscopic deformation. Additionally, temperature effects (25–650 °C) on mechanical performance were systematically evaluated. The results demonstrate that temperatures between 350 °C and 450 °C optimize formability, balancing thermal softening and strain hardening. The crystal plasticity finite element method framework provides enhanced predictive accuracy for micro–macro interactions, offering critical insights for designing biodegradable magnesium alloy implants. Full article

Magnesium alloys have attracted significant attention in recent years as biodegradable metals. However, their degradation mechanisms in vivo remain insufficiently understood. The present work investigates the degradation mechanism of AZ91 magnesium alloy in a critical-size rat defect model over an 8-week period in vivo, employing advanced characterization techniques such as transmission electron microscopy (TEM) and nanobeam electron diffraction (NBED). The degradation layer is observed to consist of three distinct sub-layers: a dense and compact poor crystallinity layer (PCL) layer primarily composed of calcium phosphate, a loose and porous amorphous layer (AL) of magnesium/calcium phosphate, and a hybrid layer (HL)layer containing degradation channels and composed of magnesium/calcium phosphate, layered double hydroxide (LDH), and magnesium hydroxide. The corrosion resistance of AZ91 is enhanced by the presence of the compact PCL layer, the uniform distribution of the Mg₁₇Al₁₂ phase, and the formation of impervious LDH at the corrosion interface. The degradation is primarily driven by micro-galvanic corrosion, which is influenced by the interaction between the Mg matrix and the Mg₁₇Al₁₂ phase. These findings provide critical insights into the stable degradation mechanism of Mg-Al alloys in vivo, advancing the development of biodegradable magnesium-based implants. Full article

Magnesium (Mg) and its alloys have emerged as promising biomaterials for orthopedic and cardiovascular applications, thanks to their good biodegradability, biocompatibility, and mechanical properties close to that of natural bone. However, the rapid degradation of Mg in physiological environments and limited mechanical performance tend to compromise the structural integrity of implants before healing is complete. These drawbacks have been heavily limiting the application of Mg and its alloys as biomaterials. In this paper, we review recent advancements in two common solutions to these problems: alloying and surface treatment, with a focus on controlling the corrosion resistance, mechanical performance, and biocompatibility of Mg-based biomaterials. Full article

Given the increasing demand for biocompatible implant materials in regenerative engineering, novel surface modification techniques are essential to enhance tissue integration, durability, and corrosion resistance. This study investigates the application of plasma electrolytic oxidation (PEO), a high-voltage anodic oxidation technique, for the surface modification of magnesium (Mg) implants. The research emphasizes both functionality enhancement and process sustainability, adhering to green chemistry principles. A comprehensive analysis was conducted to evaluate the physicochemical and biological properties of the modified surfaces. The chemical structure of the coatings was characterized using Fourier-transform infrared spectroscopy (FT-IR) and atomic absorption spectroscopy (ASA). Surface morphology and composition were examined via scanning electron microscopy (SEM), while wettability was assessed through contact angle measurements. Additionally, biodegradation and biocorrosion studies were performed to evaluate stability, and cytotoxicity was tested using MG-63 human osteosarcoma cells. Results demonstrated that carefully optimized PEO process parameters, combined with appropriate electrolyte compositions, enabled the formation of MgO coatings with significantly enhanced stability, reduced biocorrosion, and improved biocompatibility. These findings indicate the potential of surface-modified magnesium implants for advanced biomedical applications. Full article