Search Results (210)

To develop novel biodegradable magnesium alloys with suitable corrosion resistance and mechanical properties for orthopedic applications, this study investigated the microstructure, mechanical properties, corrosion behavior and wear resistance of as-cast and near-solidus heat-treated Mg-3Zn-0.3Mn alloys with and without Gd/Nd additions (RE-free, 1Gd, 1Gd1Nd). Rare earth addition refined the grains and transformed the secondary phase from Mg₇Zn₃ to the W-phase (Mg₃RE₂Zn₃). The as-cast 1Gd1Nd alloy showed the finest grains, highest hardness (51.3 HB), best tensile strength (189.38 MPa), lowest corrosion rate (2.80 mm/y) and lowest wear rate (0.614 × 10⁻³ mm³/(N·m)). Near-solidus heat treatment slightly decreased hardness (1–3%) but significantly reduced corrosion rate (e.g., RE-free alloy from 3.61 to 2.78 mm/y) and wear rate. The heat-treated 1Gd1Nd alloy gave the best overall performance: corrosion rate 2.68 mm/y, tensile strength 213.71 MPa and elongation 12.96%. Gd promoted grain refinement and film stability, while Nd stabilized the W-phase, showing a clear combined addition benefit. Notably, the heat-treated RE-free alloy performed similarly to the as-cast 1Gd1Nd alloy, indicating that heat treatment can partially mimic rare earth addition. This work provides a baseline for precursor materials before further processing (e.g., extrusion) toward biodegradable implant applications. Full article

The development of biodegradable scaffolds for load-bearing bone tissue engineering (BTE) presents a fundamental multi-criteria optimization challenge, requiring a simultaneous balance among mechanical performance, biological integration, and degradation kinetics. These criteria are inherently conflicting: composite formulations with the highest compressive strength frequently exhibit suboptimal porosity, while those with superior osteoconductivity often lack sufficient load-bearing capacity. To address this challenge rigorously, this study establishes a hybrid Fuzzy Analytic Hierarchy Process–Technique for Order of Preference by Similarity to Ideal Solution (Fuzzy AHP-TOPSIS) framework to evaluate and rank five clinically relevant biodegradable polymer–ceramic composite candidates: PLA/Hydroxyapatite (PLA/HA), PCL/Hydroxyapatite (PCL/HA), PLGA/Bioactive Glass (PLGA/BG), PLA/Carbon Nanotubes (PLA/CNT), and PLA/Magnesium (PLA/Mg). Quantitative property data were systematically extracted from ten peer-reviewed experimental studies published between 2021 and 2025, and converted into Triangular Fuzzy Numbers (TFNs) to explicitly model inter-study variability arising from differences in fabrication methods, filler loading, and testing conditions. Fuzzy AHP analysis identified Compressive Strength (w = 25.2%) and Cell Viability (w = 21.5%) as the dominant decision criteria for load-bearing cortical bone repair. The Fuzzy TOPSIS ranking identified PLA/HA as the optimal composite candidate (Closeness Coefficient, CCᵢ = 0.677), demonstrating the superior multi-criteria balance required for cortical bone repair applications. Although PLA/CNT achieved the highest mechanical strength, it was outranked due to lower osteoconductivity and elevated cytotoxicity uncertainty at high nanotube concentrations (CCᵢ = 0.544). Sensitivity analysis across five distinct weighting scenarios confirmed the robustness of PLA/HA as the primary candidate. These findings provide a validated, replicable computational blueprint for evidence-based scaffold material selection, with direct implications for reducing the burden of costly trial-and-error experimentation in BTE research. Full article

Bone tissue plays a vital role in the human body and possesses intrinsic self-repair mechanisms; however, large defects or pathological fractures may exceed its natural healing capacity. Bone tissue engineering provides promising strategies to restore bone integrity through the use of scaffolds, growth factors, and stem cells. While calcium phosphate (CaP)-based ceramics, such as hydroxyapatite (HAp) and tricalcium phosphate (TCP), represent the current benchmark, their limitations, including slow degradation (HAp) and limited osteoinductivity (TCP), have driven the development of alternative biomaterials. In this context, magnesium phosphate (MgP)-based materials have gained increasing attention due to their tunable resorption rate, improved biodegradability, and ability to stimulate osteogenesis and angiogenesis through the release of magnesium (Mg²⁺) ions. This study reports on composite scaffolds based on electrospun poly(ε-caprolactone) (PCL) fibres coated with MgP layers doped with lithium (Li) and zinc (Zn), designed to mimic the nanofibrous architecture of the extracellular matrix. Lithium and zinc were selected due to their known ability to modulate cellular response, with lithium promoting osteogenic activity and zinc contributing to improved cell proliferation and antibacterial potential. The phosphate phases obtained by coprecipitation were deposited onto the PCL fibres using Matrix-Assisted Pulsed Laser Evaporation (MAPLE), enabling controlled surface functionalization. Following thermal treatment, the formation of the crystalline magnesium pyrophosphate (Mg₂P₂O₇) phase was confirmed by chemical and structural characterization. The combination of a slowly degrading PCL matrix, providing sustained structural support, and a bioactive MgP coating, enabling rapid and controlled ion release, results in improved scaffold performance in terms of biocompatibility, biodegradability, and bioactivity. While the slow degradation rate of PCL ensures mechanical stability over an extended period, the surface-deposited MgP phase allows immediate interaction with the biological environment, facilitating faster ion release and enhancing cell–material interactions. These findings highlight the potential of the developed composites as promising candidates for trabecular bone regeneration and as viable alternatives to conventional CaP-based scaffolds in regenerative medicine. Full article

Magnesium alloys are promising materials for orthopedic applications due to their biodegradability and mechanical properties compatible with bone. However, their rapid degradation in physiological environments limits clinical use. In this study, WE43B magnesium alloy was coated with a PEO layer followed by a P(L/G/TMC) polymer applied via ultrasonic spraying. The influence of polymer layer number (10, 20, 30) on coating properties was systematically investigated. Scanning electron microscopy (SEM) analysis revealed an approximately fourfold reduction in porosity after polymer deposition, with progressive pore filling at higher layer numbers, while Fourier transform infrared spectroscopy (FT-IR) mapping indicated uniform polymer coverage. Compared to PEO alone, polymer-modified samples exhibited an approximately 7-fold increase in water contact angle, a ~50% reduction in surface roughness, and improved adhesion. Degradation-related analyses, including ion release, post-immersion SEM, and scanning acoustic microscopy (SAM), indicated that increasing polymer thickness effectively limited degradation processes. Ion release decreased by ~40–50% for the 30-layer coating compared to PEO, with the most pronounced reduction observed between the uncoated PEO and polymer-modified samples. These results demonstrate that the number of polymer layers plays a key role in controlling the barrier properties and stability of hybrid PEO/polymer coatings under simulated physiological conditions. Full article

Conventional electrochemical evaluation methods in liquid electrolytes often do not accurately replicate in vivo degradation processes, thereby posing a significant challenge in translating biodegradable magnesium-based materials from laboratory research to practical use. To address this challenge, we have developed a new in vitro analysis method using a chitosan/glycerol/Ringer’s gel that closely resembles biological tissue in terms of elemental composition and three-dimensional structure. We examined the degradation of the AZ31 magnesium alloy in both Ringer’s solution and the gel electrolyte using potentiodynamic polarization and periodic surface morphology imaging. Our results indicate that the corrosion rates and morphological features obtained from the gel electrolyte better correspond to in vivo data from animal studies, suggesting that the method can be used to accurately evaluate the corrosion resistance of magnesium alloys in vivo. Full article

Wearable health monitoring systems (WHMS) are recognized as key enablers of continuous real-time physiological sensing in healthcare, eldercare, sports, and occupational safety. However, current devices face critical limitations due to their dependence on non-renewable batteries, rigid substrates, and non-degradable electronic components, which contribute to environmental waste and limit long-term usability. This study aims to explore the development of sustainable, energy-autonomous WHMS that integrate multimodal energy harvesting, including triboelectric, piezoelectric, photovoltaic, thermoelectric, and radio frequency, with biodegradable and bioresorbable electronics using silk fibroin, cellulose nanofibers, poly(lactic-co-glycolic acid), magnesium, and transient silicon. This unified system architecture would further comprise harvesters, power management circuits, energy buffers, low-power sensing front-ends, and tiny machine learning-enabled data processing. The methodology emphasizes energy-neutral operation through duty-cycling, harvest-aware scheduling, and compressive sensing. Simulation and modeling results indicate harvested power densities between 100 and 220 µW·cm⁻², sufficient to sustain electrocardiography, photoplethysmography, and temperature monitoring under realistic daily use profiles. Material degradation studies demonstrate predictable dissolution kinetics over 8–20 weeks in physiological conditions, aligning with safety and environmental goals. By uniting sustainable materials science with energy-efficient circuit design, this work establishes a blueprint for the next generation of eco-friendly, clinically relevant, and ethically responsible wearable health technologies. Full article

Magnesium alloys’ poor corrosion resistance limits their applications as biodegradable bone repair materials. Alloying tailors Mg alloys’ microstructure and properties. The present study investigates the effect of 2 wt.% Ag addition on the microstructure and initial corrosion behavior of hot-rolled Mg-1Ca alloy. Mg-1Ca and Mg-1Ca-2Ag alloys were prepared by melting using Mg-2Ca and Mg-4Ag master alloys, followed by homogenization at 400 °C for 2 h, hot rolling, and stress-relief annealing at 400 °C for 6 h. The alloys were systematically characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). Initial corrosion behavior was evaluated via 3 h immersion tests in simulated body fluid (SBF). Results reveal Ag’s high thermal diffusivity promotes segregation at tensile twin boundaries, forming Ag₃Mg nanoparticles. These nanoparticles hinder grain boundary migration and, with increased deformation, facilitate grain rotation and high-angle grain boundary formation, weakening texture. Internal stress accumulation near twin boundaries—driven by grain orientation variation and nanoparticles—induces ~86° rotation of {10–12} tensile twins around the c-axis, forming double twins. During corrosion, nanoparticles and double twins synergistically promote dense protective film formation, significantly reducing corrosion rates. Full article

Magnesium has attracted attention as an orthopedic implant material due to its excellent biocompatibility and biodegradability; however, rapid corrosion in physiological environments remains a major limitation. In this study, a polydopamine (PDA) intermediate layer and alginate/chitosan multilayer coating were formed on pure magnesium surfaces, with dexamethasone incorporation to simultaneously improve corrosion resistance and bioactivity. SEM observation revealed that uniform coating layers were formed on alginate/chitosan multilayer coated specimens, and the chemical structure of the coating layers was confirmed through FT-IR and XRD analyses. Electrochemical analysis revealed that the PDA/alginate/chitosan coating group exhibited higher corrosion potential (Ecorr: −0.7514 ± 0.022 V vs. −1.706 ± 0.001 V) and lower corrosion current density (icorr: 2.275 ± 0.15 × 10⁻⁷ A/cm² vs. 1.528 ± 0.47 × 10⁻⁴ A/cm²) compared to pure magnesium, with the highest impedance indicating superior corrosion resistance. In tape peel testing, the polydopamine-coated group demonstrated superior adhesion compared to the non-coated group, and sustained release of dexamethasone was confirmed. MC3T3-E1 cell culture results confirmed cell proliferation in all specimens, with the PDA/alginate/chitosan group exhibiting the highest ALP activity compared to other surface-treated groups. Based on these results, the PDA/alginate/chitosan multilayer coating was confirmed to be an effective surface modification method for corrosion control and promotion of osteoblast differentiation on magnesium. Full article

Polyhydroxybutyrate (PHB) is considered a coating material capable of limiting the corrosion of biodegradable metallic implants due to its biocompatibility and ability to form a physical barrier. In this study, PHB was deposited on commercial AZ91D magnesium alloy using the spin coating technique. To improve adhesion at the polymer–substrate interface, the magnesium substrates were subjected to atmospheric pressure plasma treatment for different exposure times (5, 10, or 15 min) before coating. The optimal treatment time of 5 min significantly increased substrate wettability and surface free energy, facilitating stronger PHB adhesion. In addition, the PHB coatings were subjected to atmospheric pressure plasma treatment for 5, 10, or 15 s to evaluate potential surface modifications. Corrosion behavior under simulated physiological conditions was assessed via potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in HANK’s solution at 37 °C. Pull-off tests were used to evaluate the adhesion strength between the coating and the substrate under each treatment condition. The results showed a significant decrease in the corrosion rate (V_corr), from 4.083 mm/year for bare Mg-AZ91D to 0.001 mm/year when both the substrate and the polymer received plasma treatment. This indicates that the treatment modifies surfaces and improves interfacial bonding, enhancing polymer–metal interaction and producing durable, biocompatible coatings for medical implants. Full article

Zinc and its alloys have been regarded as an alternative option for biodegradable implant materials to magnesium and iron-based alloys due to their promising degradation rate. However, poor osseointegration with bone tissue limits their further clinical application. Considering the biofunction of strontium (Sr), namely promoting the formation of bone tissue, in this work, a ZnO-Sr composite coating was prepared on pure Zn via anodic oxidation to boost bioactivity. Surface morphology and composition of the layer were examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical measurements were carried out to assess the corrosion behaviour. Long-term immersion tests in simulated body fluid (SBF) for up to 21 days were conducted to evaluate the in vitro bioactivity. Corrosion morphology and corrosion products were studied to reveal the corrosion mechanism. The results demonstrated that the Sr-ZnO coating optimized the corrosion rate and enhanced the bioactivity of the substrate, improving its potential for orthopedic applications. Full article

Research into methods for regulating the biocorrosion rate of biodegradable magnesium implants is one of the most urgent tasks in the field of biomedical materials science. Atomic layer deposition (ALD) is a highly effective method for the preparation of nanocoatings, which can be used to regulate the biodegradation rate. The present paper presents the findings of a research study in which the most commonly used simple oxide ALD coatings (Al₂O₃, TiO₂, and ZnO) were examined, in addition to mixed coatings obtained by alternating ALD cycles of the application of ZnO-TiO₂ (ZTO) and Al₂O₃-TiO₂ (ATO). The coating thicknesses exhibited a variation within the most typical range for ALD coatings, measuring between 20 and 80 nanometres. The biocorrosion testing was conducted in Ringer’s physiological solution through the measurement of potentiodynamic polarisation curves and impedance spectroscopy. The findings demonstrated that, for Al₂O₃ coatings, the protective properties exhibited an increase with increasing thickness, while for TiO₂, the trend was found to be dependent on the type of precursor utilised. The protective properties of titanium tetraisopropoxide (TTIP) have been observed to increase with increasing thickness. Conversely, the protective properties of titanium tetrachloride (TiCl₄) have been observed to decrease. The application of mixed ZTO oxides with a thickness of 40 nm has been demonstrated to reduce the corrosion current by 1.7 and 3.4 times, depending on the use of TiCl₄ or TTIP. Furthermore, the effectiveness of ATO coatings of similar thicknesses has been shown to be higher, with a reduction in corrosion currents of 54 and 24 times for samples obtained using TiCl₄ and TTIP, respectively. A thorough analysis of the collected data unequivocally demonstrates the superior efficacy of mixed oxides in comparison to their pure oxide counterparts. Full article

In physiological environments, several metallic alloys, including titanium, stainless steel, cobalt–chromium, and emerging biodegradable systems such as magnesium (Mg), zinc (Zn), and iron (Fe), offer mechanical properties and biocompatibility suitable for load-bearing implants. With the rapid advancement of 3D printing technologies, these alloys can now be fabricated into patient-specific, complex geometries that enhance both structural performance and functional integration. Beyond serving as structural supports, 3D-printed alloys are increasingly engineered as localized drug-delivery platforms to release anti-inflammatory, antibacterial, anticancer, and osteogenic agents at the implant–tissue interface, addressing the dual clinical needs of site-specific therapy and mechanical stabilization. Nevertheless, this field remains underexplored because studies differ widely in alloy chemistry, surface topography, porosity, coating strategy, drug-loading methods, and release profiles, as well as in how material degradation or passivation interacts with pharmacokinetics. For the first time, this review consolidates drug-loading and elution strategies across 3D-printed alloy platforms, compares therapeutic categories in relation to alloy and coating types, and critically evaluates how the surface microstructure or alloy geometry influences release behavior. Full article

Conventional dental materials with organised crystal structures exhibit limitations in corrosion resistance, bioactivity, and drug delivery capability. In contrast, amorphous nanomaterials offer potential advantages in overcoming these limitations due to their unique structural properties. They are characterised by a non-crystalline, disordered atomic structure and are similar to a solidified liquid at the nanoscale. Among the amorphous nanomaterials used in dentistry, there are five major categories: calcium-, silicon-, magnesium-, zirconia-, and polymer-based systems. This study reviewed these amorphous nanomaterials by investigating their synthesis, properties, applications, limitations, and future directions in dentistry. These amorphous nanomaterials are synthesised primarily through low-temperature methods, including sol–gel processes, rapid precipitation, and electrochemical etching, which prevent atomic arrangements into crystalline structures. The resulting disordered atomic configuration confers exceptional properties, including enhanced solubility, superior drug-loading capacity, high surface reactivity, and controlled biodegradability. These characteristics enable diverse dental applications. Calcium-based amorphous nanomaterials, particularly amorphous calcium phosphate, demonstrate the ability to remineralise tooth enamel. Silicon-based amorphous nanomaterials function as carriers that can release antibacterial agents in response to stimuli. Magnesium-based amorphous nanomaterials are antibacterial and support natural bone regeneration. Zirconia-based amorphous nanomaterials strengthen the mechanical properties of restorative materials. Polymer-based amorphous nanomaterials enable controlled release of medications over extended periods. Despite the advances in these amorphous nanomaterials, there are limitations regarding material stability over time, precise control of degradation rates in the oral environment, and the development of reliable large-scale manufacturing processes. Researchers are creating smart materials that respond to specific oral conditions and developing hybrid systems that combine the strengths of different nanomaterials. In summary, amorphous nanomaterials hold great promise for advancing dental treatments through their unique properties and versatile applications. Clinically, these materials could improve the durability, bioactivity, and targeted drug delivery in dental restorations and therapies, leading to better patient outcomes. Full article

Magnesium alloys are promising biodegradable orthopedic implant materials, but their clinical translation is hindered by rapid, unregulated corrosion in physiological environments. Polyvinylidene fluoride (PVDF) coating has attracted substantial attention for addressing the issue above. However, it suffers from insufficient interfacial adhesion to Mg alloy substrates. In this work, we propose a Zr-based pretreatment strategy to enhance PVDF coatings. The pretreatment was performed via a chemical conversion deposition method, which fabricated a Zr-based film on AZ31 magnesium alloy and greatly promoted the adhesion of the following PVDF coating. Interface analysis showed that coating adhesion was improved from 0.44 MPa to 2.48 MPa. In light of this, corrosion protection performance was significantly improved. Electrochemical tests in simulated body fluid revealed the enhanced PVDF coating shifted the corrosion potential from −1.594 V to −1.392 V and reduced the corrosion current density by over five orders of magnitude. Immersion tests also showed stable pH level, low weight loss, and good hydrophobicity with the enhanced PVDF coating. In summary, the enhanced PVDF coating provides excellent corrosion protection for magnesium alloys, thus boosting their biomedical use. Full article

Biodegradable magnesium (Mg) alloys are promising materials for temporary orthopaedic implants, combining favourable mechanical properties and superplastic behaviour with in vivo resorption. This enables (i) prolonged implant duration, (ii) fabrication of complex-shaped prostheses via superplastic forming (SPF), (iii) elimination of removal surgery, and (iv) reduced risk of long-term complications. However, rapid corrosion under physiological conditions remains a major limitation, highlighting the need for surface treatments that slow degradation while preserving implant integrity. This study investigates the effects of hydrothermal surface treatment on MgAZ31-SPF alloys, focusing on immunomodulatory responses, antibacterial potential, and degradation behaviour. Hydrothermally treated MgAZ31-SPF (MgAZ31-SPF-HT) extracts released lower Mg²⁺ concentrations (29.2 mg/dL) compared to untreated MgAZ31-SPF (47.5 mg/dL) while maintaining slightly alkaline pH (7–8.7), indicating improved control of early degradation. In vitro assays with human peripheral blood mononuclear cells (hPBMCs) and normal human dermal cells (NHDCs) showed that MgAZ31-SPF-HT extracts maintained higher cell viability over 24–72 h. Gene expression analysis revealed significant downregulation of pro-inflammatory markers CTSE and TNF-α, while protein quantification via ELISA and BioPlex confirmed reduced secretion of TNF-α, TGF-β1, TGF-β2, IL-6, and IL-8, suggesting mitigation of early immune activation. Antibacterial assays demonstrated limited Staphylococcus aureus colonisation on both MgAZ31-SPF and MgAZ31-SPF-HT scaffolds, with CFU counts (~10⁵–10⁶) well below the threshold for mature biofilm formation (~10⁸), and SEM analysis confirmed sparse bacterial distribution without dense EPS-rich layers. Overall, hydrothermal treatment improves Mg alloy biocompatibility by controlling Mg²⁺ release, modulating early immune responses, and limiting bacterial adhesion, highlighting its potential to enhance clinical performance of Mg-based implants. Full article