Advancements in three-dimensional titanium alloy mesh scaffolds fabricated by electron beam melting for biomedical devices: mechanical and biological aspects

Previous strategies for controlling the surface morphologies of polyvinyl alcohol (PVA)-based hydrogels, including freeze-drying and electrospinning, require a posttreatment process, which can affect the final textures and properties of the hydrogels. Of particular interest, it is almost impossible to control the surface morphology during the formation of PVA hydrogels using these approaches. The strategy reported in this study used the novel vortex fluidic device (VFD) technology, which for the first time provided an opportunity for one-step fabrication of PVA hydrogel films. PVA hydrogels with different surface morphologies could be readily fabricated using a VFD. By also reducing the crosslinking agent concentration, a self-healing gel with enhanced fracture stress (60% greater than that of traditionally made hydrogel) was achieved. Interestingly, the associated selfhealing property remained unchanged during the 260-s mechanical testing performed with the strain rate of 5% s −1. The VFD can effectively tune the surface morphologies of the PVA-based hydrogels and their associated properties, particularly the self-healing property.

Section: Resultsmentioning

confidence: 96%

Vortex fluidic mediated one-step fabrication of polyvinyl alcohol hydrogel films with tunable surface morphologies and enhanced self-healing properties

Tavakoli

Raston

et al. 2020

“…Recently, extrusion-based three-dimensional (3D) printing technology has been widely applied for producing biomaterials in regenerative medicine and promoted significant innovations [18][19][20][21][22]. During printing, viscoelastic inks are extruded out of a 3D printer's nozzle as printed fibers, which are deposited into patterns layer by layer when the nozzle moves [23,24].…”

Section: Introductionmentioning

confidence: 99%

4-Axis printing microfibrous tubular scaffold and tracheal cartilage application

Lei

Guo

et al. 2019

Long-segment defects remain a major problem in clinical treatment of tubular tissue reconstruction. The design of tubular scaffold with desired structure and functional properties suitable for tubular tissue regeneration remains a great challenge in regenerative medicine. Here, we present a reliable method to rapidly fabricate tissueengineered tubular scaffold with hierarchical structure via 4axis printing system. The fabrication process can be adapted to various biomaterials including hydrogels, thermoplastic materials and thermosetting materials. Using polycaprolactone (PCL) as an example, we successfully fabricated the scaffolds with tunable tubular architecture, controllable mesh structure, radial elasticity, good flexibility, and luminal patency. As a preliminary demonstration of the applications of this technology, we prepared a hybrid tubular scaffold via the combination of the 4-axis printed elastic poly(glycerol sebacate) (PGS) bio-spring and electrospun gelatin nanofibers. The scaffolds seeded with chondrocytes formed tubular mature cartilage-like tissue both via in vitro culture and subcutaneous implantation in the nude mouse, which showed great potential for tracheal cartilage reconstruction.

“…Titanium (Ti) and some of its alloys have been widely utilized in the medical field due to their high specific strength, excellent corrosion resistance, and biocompatibility in the human body environment [1][2][3][4][5]. However, current widely-used Ti alloys, such as extra-low interstitial (ELI) Ti-6Al-4V (wt.% hereafter), Ti-5Al-2.5Fe and Ti-6Al-7Nb, have the risk of releasing toxic aluminum (Al) and vanadium (V) ions in vivo, which can cause health-related problems, e.g., Alzheimer's disease and neuropathy [6].…”

Section: Introductionmentioning

confidence: 99%

Porous Ti-10Mo alloy fabricated by powder metallurgy for promoting bone regeneration

Liu

et al. 2019

Porous Ti-10Mo alloys were fabricated by powder metallurgy using a space-holder method. The pore characteristics, microstructure, mechanical properties, in vitro biocompatibility, and in vivo osseointegration of the fabricated alloys were systematically investigated. The results show that with different weight ratios of the space-holder (NH 4-HCO 3) added, all of the porous Ti-10Mo alloys sintered at 1,300°C exhibited a typical Widmanstätten microstructure. The porosity and average pore size of the porous structures can be controlled in the range of 50.8%-66.9% and 70.1-381.4 μm, respectively. The Ti-10Mo alloy with 63.4% porosity exhibited the most suitable mechanical properties for implant applications with an elastic modulus of 2.9 GPa and a compressive yield strength of 127.5 MPa. In vitro, the alloyconditioned medium showed no deleterious effect on the cell proliferation. The cell viability in this medium was higher than that of the reference group, suggesting non-toxicity and good biological characteristics of the alloy specimens. In vivo, after eight weeks' implantation, new bone tissue formed surrounding the alloy implants, and no noticeable inflammation was observed at the implantation site. The bone bonding strength of the porous Ti-10Mo alloy increased over time from 46.6 N at two weeks to 176.4 N at eight weeks. Suitable mechanical properties together with excellent biocompatibility in vitro and osteointegration in vivo make the porous Ti-10Mo fabricated by powder metallurgy an attractive orthopedic implant alloy.