Synthesis and Characterization of a Novel Biocompatible Alloy, Ti-Nb-Zr-Ta-Sn

Design and Biofunctionalization of Cloud Sponge-Inspired Scaffolds for Enhanced Bone Cell Performance

With the increasing age of our population, which is linked to a higher incidence of musculoskeletal diseases, there is a massive clinical need for bone implants. Porous scaffolds, usually offering a lower stiffness and allowing for the ingrowth of blood vessels and nerves, serve as an attractive alternative to conventional implants. Natural porous skeletons from marine sponges represent an array of evolutionarily optimized patterns, inspiring the design of biomaterials. In this study, cloud sponge-inspired scaffolds were designed and printed from a photocurable polymer, Clear Resin. These scaffolds were biofunctionalized by mussel-derived peptide MP-RGD, a recently developed peptide that contains a cyclic, bioactive RGD cell adhesion motif and catechol moieties, which provide the anchoring of the peptide to the surface. In in vitro cell culture assays with bone cells, significantly higher biocompatibility of three scaffolds, i.e., square, octagon, and hexagon cubes, in comparison to hollow and sphere inside cubes was shown. The performance of the cells regarding signaling was further enhanced by applying an MP-RGD coating. Consequently, these data demonstrate that both the structure of the scaffold and the coating contribute to the biocompatibility of the material. Three out of five MP-RGD-coated sponge-inspired scaffolds displayed superior biochemical properties and might guide material design for improved bone implants.

Assessing Microstructural, Biomechanical, and Biocompatible Properties of TiNb Alloys for Potential Use as Load-Bearing Implants

Titanium-Niobium (TiNb) alloys are commonly employed in a number of implantable devices, yet concerns exist regarding their use in implantology owing to the biomechanical mismatch between the implant and the host tissue. Therefore, to balance the mechanical performance of the load-bearing implant with bone, TiNb alloys with differing porosities were fabricated by powder metallurgy combined with spacer material. Microstructures and phase constituents were characterized with energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The mechanical properties were tested by uniaxial compression, and the corrosion performance was determined via a potentiodynamic polarization experiment. To evaluate a highly matched potential implant with the host, biocompatibilities such as cell viability and proliferation rate, fibronectin adsorption, plasmid-DNA interaction, and an SEM micrograph showing the cell morphology were examined in detail. The results showed that the alloys displayed open and closed pores with a uniform pore size and distribution, which allowed for cell adherence and other cellular activities. The alloys with low porosity displayed compressive strength between 618 MPa and 1295 MPa, while the alloys with high porosity showed significantly lower strength, ranging from 48 MPa to 331 MPa. The biological evaluation of the alloys demonstrated good cell attachment and proliferation rates.

The Effect of Solution Treatment Duration on the Microstructural and Mechanical Properties of a Cold-Deformed-by-Rolling Ti-Nb-Zr-Ta-Sn-Fe Alloy

The study presented in this paper is focused on the effect of varying the solution treatment duration on both the microstructural and mechanical properties of a cold-deformed by rolling Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) alloy, referred to as TNZTSF. Cold-crucible induction using the levitation synthesis technique, conducted under an argon-controlled atmosphere, was employed to fabricate the TNZTSF alloy. After synthesis, the alloy underwent cold deformation by rolling, reaching a total deformation degree (total applied thickness reduction) of 60%. Subsequently, a solution treatment was conducted at 850 °C, with varying treatment durations ranging from 2 to 30 min in 2 min increments. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized for the structural analysis, while the mechanical properties were assessed using both tensile and hardness testing. The findings indicate that (i) in both the cold-deformed-by-rolling and solution-treated states, the TNZTSF alloy exhibits a microstructure consisting of a single β-Ti phase; (ii) in the solution-treated state, the microstructure reveals a rise in the average grain size and a decline in the internal average microstrain as the duration of the solution treatment increases; and (iii) owing to the β-phase stability, a favorable mix of elevated strength and considerable ductility properties can be achieved.

Multidimensional analysis for the correlation of physico-chemical attributes to osteoblastogenesis in TiNbZrSnTa alloys

Data-enabled approaches that complement experimental testing offer new capabilities to investigate the interplay between chemical, physical and mechanical attributes of alloys and elucidate their effect on biological behaviours. Reported here, instead of physical causation, statistical correlations were used to study the factors responsible for the adhesion, proliferation and maturation of pre-osteoblasts MC3T3-E1 cultured on Titanium alloys. Eight alloys with varying wt% of Niobium, Zirconium, Tin and Tantalum (Ti- (2-22 wt%)Nb- (5-20 wt%)Zr- (0-18 wt%)Sn- (0-14 wt%)Ta) were designed to achieve exemplars of allotropes (incl., metastable-β, β + α', α″). Following confirmation of their compositions (ICP, EDX) and their crystal structure (XRD, SEM), their compressive bulk properties were measured and their surface features characterised (XPS, SFE). Because these alloys are intended for the manufacture of implantable orthopaedic devices, the correlation focuses on the effect of surface properties on cellular behaviour. Physico-chemical attributes were paired to biological performance, and these highlight the positive interdependencies between oxide composition and proliferation (esp. Ti4+), and maturation (esp. Zr4+). The correlation reveals the negative effect of oxide thickness, esp. TiOx and TaOx on osteoblastogenesis. This study also shows that the characterisation of the chemical state and elemental electronic structure of the alloys' surface is more predictive than physical properties, namely SFE and roughness.

Mechanical Properties, Corrosion Behavior, and In Vitro Cell Studies of the New Ti-25Ta-25Nb-5Sn Alloy

This study aims to characterize a new Ti-25Ta-25Nb-5Sn alloy for biomedical application. Microstructure, phase formation, mechanical and corrosion properties, along with the cell culture study of the Ti-25Ta-25Nb alloy with Sn content 5 mass% are presented in this article. The experimental alloy was processed in an arc melting furnace, cold worked, and heat treated. For characterization, optical microscopy, X-ray diffraction, microhardness, and Young's modulus measurements were employed. Corrosion behavior was also evaluated using open-circuit potential (OCP) and potentiodynamic polarization. In vitro studies with human ADSCs were performed to investigate cell viability, adhesion, proliferation, and differentiation. Comparison among the mechanical properties observed in other metal alloy systems, including CP Ti, Ti-25Ta-25Nb, and Ti-25Ta-25-Nb-3Sn showed an increase in microhardness and a decrease in the Young's modulus when compared to CP Ti. The potentiodynamic polarization tests indicated that the corrosion resistance of the Ti-25Ta-25Nb-5Sn alloy was similar to CP Ti and the experiments in vitro demonstrated great interactions between the alloy surface and cells in terms of adhesion, proliferation, and differentiation. Therefore, this alloy presents potential for biomedical applications with properties required for good performance.