In vitro biocompatibility assessment of Ti40Cu38Zr10Pd12 bulk metallic glass

Osteogenesis and angiogenesis of a bulk metallic glass for biomedical implants

Implantation is an essential issue in orthopedic surgery. Bulk metallic glasses (BMGs), as a kind of novel materials, attract lots of attentions in biological field owing to their comprehensive excellent properties. Here, we show that a Zr61Ti2Cu25Al12 (at. %) BMG (Zr-based BMG) displays the best cytocompatibility, pronounced positive effects on cellular migration, and tube formation from in-vitro tests as compared to those of commercial-pure titanium and poly-ether-ether-ketone. The in-vivo micro-CT and histological evaluation demonstrate the Zr-based BMG can significantly promote a bone formation. Immunofluorescence tests and digital reconstructed radiographs manifest a stimulated effect on early blood vessel formation from the Zr-based BMG. Accordingly, the intimate connection and coupling effect between angiogenesis and osteogenesis must be effective during bone regeneration after implanting Zr-based BMG. Dynamic gait analysis in rats after implanting Zr-based BMG demonstrates a tendency to decrease the pain level during recovery, simultaneously, without abnormal ionic accumulation and inflammatory reactions. Considering suitable mechanical properties, we provide a realistic candidate of the Zr61Ti2Cu25Al12 BMG for biomedical applications.

Biological performance of metal metalloid (TiCuZrPd:B) TFMG fabricated by pulsed laser deposition

The aim of our study is to investigate the effect of boron with different ratios in Ti-Cu-Pd-Zr metallic glass (MG) matrix (Ti-Cu-Pd-Zr:B) fabricated by Pulsed Laser Deposition (PLD) for biomedical implants. The Ti based Thin Film Metallic Glasses (TFMGs) in combination with boron (in different atomic %) was assessed in attaining the combined properties, like outstanding corrosion resistant properties and good biocompatibility in this work. The disordered structure and amorphous nature of the Ti-Cu-Pd-Zr:B thin films systems were achieved by the PLD process and affirmed by XRD and transmission electron microscopy. The boron incorporation in the TFMG has been elucidated by XPS analysis. The boron containing films displays distribution of boron protuberances interleaved in the amorphous matrix was stated from SEM analysis. It is found that increase in atomic percentage of boron contents in TFMG results in the improvement in glass transition temperatures. The electrochemical parameters suggest better corrosion resistance and capabilities of passivity when boron percentage was increased in the film thereby preventing adverse biological reactions. TFMGs exhibited excellent hemocompatibility by preventing the platelet activation. MTT assay manifests increase in cell concentration with culture period on the TFMGs for the MC3T3-E1 preosteoblasts cells. Cell morphology was also studied which confirmed the viable state of the cells on the TFMG surfaces. The combination of such distinctive properties marks these TFMG systems as prospective aspirants for biomedical implants.

Application of Zr and Ti-Based Bulk Metallic Glasses for Orthopaedic and Dental Device Materials

Conventional orthopaedic and dental device materials are made of metallic materials such as stainless steel (SUS316L), titanium alloy (Ti-6Al-4V), and cobalt-chrome (Co-Cr). Those materials have the disadvantage of mechanical properties and anti-corrosion behavior. Bulk metallic glasses (BMGs), which are also called amorphous alloys, are metallic materials with metastable glassy states and have a higher strength, higher elasticity, higher failure resistance, and lower Young’s modulus compared with crystalline alloys. There are several types of BMGs. Among them, Zr-based BMGs and Ti-based BMGs have excellent mechanical properties. In addition, they have good corrosion resistance and are promising for orthopaedic and dental device materials. In this review article, in vitro and in vivo studies regarding Zr and Ti-based BMGs applications as biomaterials, especially in orthopaedic and dental device materials, are reviewed.

Copper-Modified Ti6Al4 V Suppresses Inflammatory Response and Osteoclastogenesis while Enhancing Extracellular Matrix Formation for Osteoporotic Bone Regeneration

Copper has been reported to promote bone regeneration by increasing osteogenesis and decreasing inflammation and osteoclastogenesis. However, information on the effects of copper on osteoporotic cells involved in bone regeneration is scarce in the literature. In the current study, Ti6Al4 V-6 wt %Cu (Ti6Al4 V-Cu) was fabricated by selective laser melting (SLM) technology, and the effects of copper on the behaviors of osteoporotic and nonosteoporotic macrophages, osteoclasts, and osteoblasts were evaluated by comparison with Ti6Al4 V. Our results showed that Ti6Al4 V-Cu inhibited the activation, viability, and pro-inflammatory cytokine secretion of osteoporotic macrophages and decreased osteoclast formation and down-regulated osteoclast differentiation-related genes and proteins of osteoporotic osteoclasts. Furthermore, the bone extracellular matrix formation of osteoporotic osteoblasts was up-regulated by Ti6Al4 V-Cu. In conclusion, SLM-fabricated Ti6Al4 V-Cu exhibited excellent anti-inflammation and antiosteoclast capability, optimized extracellular matrix formation, and holds great potential for bone regeneration in osteoporotic patients.

On the Potential of Bulk Metallic Glasses for Dental Implantology: Case Study on Ti40Zr10Cu36Pd14

Ti₄₀Zr₁₀Cu₃₆Pd₁₄ Bulk Metallic Glass (BMG) appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For the first time, a complete and exhaustive characterization of a unique batch of this glassy alloy was performed, together with ISO standard mechanical tests on machined implant-abutment assemblies. The results were compared to the benchmark Ti-6Al-4V ELI (Extra-Low-Interstitial) to assess its potential in dental implantology. The thermal stability, corrosion and sterilization resistance, cytocompatibility and mechanical properties were measured on samples with a simple geometry, but also on implant-abutment assemblies’ prototypes. Results show that the glassy alloy exhibits a quite high thermal stability, with a temperature range of 38 °C between the glass transition and crystallization, a compressive strength of 2 GPa, a certain plastic deformation (0.7%), a hardness of 5.5 GPa and a toughness of 56 MPa.√m. Moreover, the alloy shows a relatively lower Young’s modulus (96 GPa) than the Ti-6Al-4V alloy (110–115 GPa), which is beneficial to limit bone stress shielding. The BMG shows a satisfactory cytocompatibility, a high resistance to sterilization and a good corrosion resistance (corrosion potential of −0.07 V/SCE and corrosion current density of 6.0 nA/cm²), which may ensure its use as a biomaterial. Tests on dental implants reveal a load to failure 1.5-times higher than that of Ti-6Al-4V and a comparable fatigue limit. Moreover, implants could be machined and sandblasted by methods usually conducted for titanium implants, without significant degradation of their amorphous nature. All these properties place this metallic glass among a promising class of materials for mechanically-challenging applications such as dental implants.

Effect of Surface Modifications of Ti40Zr10Cu38Pd12 Bulk Metallic Glass and Ti-6Al-4V Alloy on Human Osteoblasts In Vitro Biocompatibility

The use of biocompatible materials, including bulk metallic glasses (BMGs), for tissue regeneration and transplantation is increasing. The good mechanical and corrosion properties of Ti₄₀Zr₁₀Cu₃₈Pd₁₂ BMG and its previously described biocompatibility makes it a potential candidate for medical applications. However, it is known that surface properties like topography might play an important role in regulating cell adhesion, proliferation and differentiation. Thus, in the present study, Ti₄₀Zr₁₀Cu₃₈Pd₁₂ BMG and Ti6-Al-4V alloy were surface-modified electrochemically (nanomesh) or physically (microscratched) to investigate the effect of material topography on human osteoblasts cells (Saos-2) adhesion, proliferation and differentiation. For comparative purposes, the effect of mirror-like polished surfaces was also studied. Electrochemical treatments led to a highly interconnected hierarchical porous structure rich in oxides, which have been described to improve corrosion resistance, whereas microscratched surfaces showed a groove pattern with parallel trenches. Cell viability was higher than 96% for the three topographies tested and for both alloy compositions. In all cases, cells were able to adhere, proliferate and differentiate on the alloys, hence indicating that surface topography plays a minor role on these processes, although a clear cell orientation was observed on microscratched surfaces. Overall, our results provide further evidence that Ti₄₀Zr₁₀Cu₃₈Pd₁₂ BMG is an excellent candidate, in the present two topographies, for bone repair purposes.

In vivo evaluation of a Ti-based bulk metallic glass alloy bar

Ti-based bulk metallic glasses are reported with high strength, low Young modulus and high corrosion resistance, suggesting their potentials in biomedical applications. However a thorough in vivo evaluation of its biocompatibilities has not been conducted yet. In this study, we implanted bars of Ti-based bulk metallic glass in the femoral bone of rats, followed up local tissue reaction as well as its component ions' diffusion in local area and whole body. The Ti-based BMG (Ti40Zr10Cu34Pd14Sn2) alloy exhibited favorable features of both high strength and high elasticity. In vivo implant evaluation showed that it has a good tissue compatibility, equivalent bone integration and bonding ability with Ti sample. No component ion diffusion was detected up to 3 months post implantation. The possibility and efficacy of its use for bone implant is confirmed. Thus further long term implant study is recommended.

Nanostructured Ti-Zr-Pd-Si-(Nb) bulk metallic composites: Novel biocompatible materials with superior mechanical strength and elastic recovery

The microstructure, mechanical behaviour, and biocompatibility (cell culture, morphology, and cell adhesion) of nanostructured Ti45 Zr15 Pd35- x Si5 Nbx with x = 0, 5 (at. %) alloys, synthesized by arc melting and subsequent Cu mould suction casting, in the form of rods with 3 mm in diameter, are investigated. Both Ti-Zr-Pd-Si-(Nb) materials show a multi-phase (composite-like) microstructure. The main phase is cubic β-Ti phase (Im3m) but hexagonal α-Ti (P63/mmc), cubic TiPd (Pm3m), cubic PdZr (Fm3m), and hexagonal (Ti, Zr)5 Si3 (P63/mmc) phases are also present. Nanoindentation experiments show that the Ti45 Zr15 Pd30 Si5 Nb5 sample exhibits lower Young's modulus than Ti45 Zr15 Pd35 Si5 . Conversely, Ti45 Zr15 Pd35 Si5 is mechanically harder. Actually, both alloys exhibit larger values of hardness when compared with commercial Ti-40Nb, (HTi-Zr-Pd-Si ≈ 14 GPa, HTi-Zr-Pd-Si-Nb ≈ 10 GPa and HTi-40Nb ≈ 2.7 GPa). Concerning the biological behaviour, preliminary results of cell viability performed on several Ti-Zr-Pd-Si-(Nb) discs indicate that the number of live cells is superior to 94% in both cases. The studied Ti-Zr-Pd-Si-(Nb) bulk metallic system is thus interesting for biomedical applications because of the outstanding mechanical properties (relatively low Young's modulus combined with large hardness), together with the excellent biocompatibility.