Electrocatalytic Degradation of Phenolic Wastewater Using a Zero-Gap Flow-Through Reactor Coupled with a 3D Ti/RuO2-TiO2@Pt Electrode.

In this study, the performance of a zero-gap flow-through reactor with three-dimensional (3D) porous Ti/RuO2-TiO2@Pt anodes was systematically investigated for the electrocatalytic oxidation of phenolic wastewater, considering phenol and 4-nitrophenol (4-NP) as the target pollutants. The optimum parameters for the electrochemical oxidation of phenol and 4-NP were examined. For phenol degradation, at an initial concentration of 50 mg/L, initial pH of 7, NaCl concentration of 10.0 g/L, current density of 10 mA/cm2, and retention time of 30 min, the degradation efficiency achieved was 95.05%, with an energy consumption of 15.39 kWh/kg; meanwhile, for 4-NP, the degradation efficiency was 98.42% and energy consumption was 19.21 kWh/kg (at an initial concentration of 40 mg/L, initial pH of 3, NaCl concentration of 10.0 g/L, current density of 10 mA/cm2, and retention time of 30 min). The electrocatalytic oxidation of phenol and 4-NP conformed to the pseudo-first-order kinetics model, and the k values were 0.2562 min-1 and 0.1736 min-1, respectively, which are 1.7 and 3.6-times higher than those of a conventional electrolyzer. Liquid chromatography-mass spectrometry (LC-MS) was used to verify the intermediates formed during the degradation of phenol or 4-NP and a possible degradation pathway was provided. The extremely narrow electrode distance and the flow-through configuration of the zero-gap flow-through reactor were thought to be essential for its lower energy consumption and higher mass transfer efficiency. The zero-gap flow-through reactor with a novel 3D porous Ti/RuO2-TiO2@Pt electrode is a superior alternative for the treatment of industrial wastewater.

Schwann Cell-derived exosomes promote bone regeneration and repair by enhancing the biological activity of porous Ti6Al4V scaffolds.

Implants made of porous titanium alloy and fabricated by 3D printing are increasingly used in clinical research. However, porous titanium alloys do not integrate very well with surrounding bone tissue, and bone ingrowth into the implants is not substantial. Schwann cells (SCs) and SC-derived exosomes can effectively promote nerve regeneration, but their role in bone tissue regeneration and repair has not been studied. Therefore, we added SC-derived exosomes to bone marrow stromal cell (BMSC) cultures and observed their effect on BMSCs in vitro; then, we combined exosomes with porous Ti6Al4V scaffolds and observed their effects on bone regeneration and repair in vivo. We found that SC-derived exosomes could promote the migration, proliferation and differentiation of BMSCs and that combining exosomes with porous titanium alloy can effectively improve the efficacy of titanium alloy scaffolds in bone repair. The combination of exosomes and porous Ti6Al4V implants may constitute a new therapeutic strategy for treating bone defects.

A Comparison of 1- and 3.2-MHz Low-Intensity Pulsed Ultrasound on Osteogenesis on Porous Titanium Alloy Scaffolds: An In Vitro and In Vivo Study.

OBJECTIVES: Low-intensity pulsed ultrasound (LIPUS) combined with porous scaffolds can be used as a new therapy to treat bone defect repair. The aim of this study was to evaluate the effects of 1 and 3.2 MHz LIPUS on osteogenesis on porous Ti64 alloy scaffolds for both in vitro and in vivo studies. METHODS: Scaffolds were randomly divided into the high-frequency ultrasound group, low-frequency ultrasound group, and control group. Mouse pre-osteoblast cells were cultured with porous Ti-6Al-4V scaffolds in vitro to evaluate cell proliferation and differentiation. In addition, scaffolds were implanted into rabbit mandibular defects in vivo. The effects of LIPUS on bone regeneration were evaluated by observing the micro-computed tomography (micro-CT), toluidine blue staining, and von Kossa staining. RESULTS: The results revealed no significant difference in the cell counting kit-8 values between the ultrasound groups and control groups (P > .05). Compared with the control group, ultrasound promoted alkaline phosphatase activity and osteocalcin levels of the cells on the scaffolds (P < .05), but there was no significant difference between the two frequencies. In addition, histomorphologic analyses revealed that the volume and amount of new bone formation increased and that bone maturity improved in the ultrasound groups compared with the control group, but no significant difference was noted between the two frequencies. CONCLUSIONS: Under the present experimental conditions, LIPUS promoted osteoblast differentiation and promoted bone maturity on porous Ti64 scaffolds. No significant differences were noted between the two frequencies.

Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride.

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate.

In vivo evaluation of osseointegration ability of sintered bionic trabecular porous titanium alloy as artificial hip prosthesis.

Hydroxyapatite (HA) coatings have been widely used for improving the bone-implant interface (BII) bonding of the artificial joint prostheses. However, the incidence of prosthetic revisions due to aseptic loosening remains high. Porous materials, including three-dimensional (3D) printing, can reduce the elastic modulus and improve osseointegration at the BII. In our previous study, we identified a porous material with a sintered bionic trabecular structure with in vitro and in vivo bio-safety as well as in vivo mechanical safety. This study aimed to compare the difference in osseointegration ability of the different porous materials and HA-coated titanium alloy in the BII. We fabricated sintered bionic trabecular porous titanium acetabular cups, 3D-printed porous titanium acetabular cups, and HA-coated titanium alloy acetabular cups for producing a hip prosthesis suitable for beagle dogs. Subsequently, the imaging and histomorphological analysis of the three materials under mechanical loading in animals was performed (at months 1, 3, and 6). The results suggested that both sintered bionic porous titanium alloy and 3D-printed titanium alloy exhibited superior performances in promoting osseointegration at the BII than the HA-coated titanium alloy. In particular, the sintered bionic porous titanium alloy exhibited a favorable bone ingrowth performance at an early stage (month 1). A comparison of the two porous titanium alloys suggested that the sintered bionic porous titanium alloys exhibit superior bone in growth properties and osseointegration ability. Overall, our findings provide an experimental basis for the clinical application of sintered bionic trabecular porous titanium alloys.

Enhanced decomposition of long-chain perfluorocarboxylic acids (C9-C10) by electrochemical activation of peroxymonosulfate in aqueous solution.

The decomposition of long-chain perfluorocarboxylic acids (PFCAs), including perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), were investigated by electrochemical activation of peroxymonosulfate (PMS) on porous Ti/SnO2-Sb membrane anode. The results indicated that PMS activation could efficiently promote PFNA/PFDA decomposition, with pseudo-first-order rate constants about 3.12/2.06 times as compared with that of direct electro-oxidations. The energy consumptions of PFNA and PFDA decomposition were 36.31 and 37.46 kWh·m-3·order-1, respectively. The quantitative detection results of •OH with electron paramagnetic resonance (EPR) demonstrated that PMS activation promoted •OH formation. The inhibited performance in radical scavengers indicated both •OH and SO4•- might be mainly involved in PFNA decomposition, while SO4•- might be mainly involved in PFDA decomposition during PMS activation process. The mineralization mechanism for long-chain PFCAs decomposition which was mainly by repeating CF2-unzipping cycle via radical reaction based on the intermediates verification and mass balance of C and F, was proposed. These results suggested that electrochemical activation of PMS on porous Ti/SnO2-Sb membrane anode exhibited high efficiency in mineralizing PFNA and PFDA under mild conditions. This work might provide an efficient way for persistent organic pollutants, including, but not limited to long-chain PFCAs elimination from wastewater.

Corrosion and wear behaviour of highly porous Ti-TiB-TiNx in situ composites in simulated physiological solution.

Highly porous Ti matrix composites can be a solution for some of the major clinical concerns for the load bearing implants such as low tribocorrosion resistance, stress shielding, and lack of biological anchorage. In order to respond to these needs, highly porous Ti-TiB-TiNx in-situ composites were synthesized by pressureless sintering using BN as reactant and urea as space holder. Corrosion behaviour was investigated at body temperature, in phosphate buffer saline solution (PBS), by measuring open circuit potential (OCP) and cyclic polarization. Wear behaviour was studied in PBS by reciprocating against a 10 mm diameter alumina ball under 3 N of normal load and 1 Hz of frequency. Results showed that the formation of the in-situ reinforcing phases led to an increase on the hardness and on the wear resistance, as well, neither macro porosity nor the reinforcing phases led to localized corrosion.

Microstructure, mechanical property and corrosion behavior of porous Ti-Ta-Nb-Zr.

In this paper, biomedical porous Ti-Nb-Ta-Zr with 40% porosity and 166 ± 21 µm macro-pore size was successfully fabricated by space holder method. The microstructure, Vickers hardness, compressive and electrochemistry behavior were studied. It results that a few second phases exist in ß matrix of the porous Ti-Nb-Ta-Zr. Its Young's modulus is 0.8 GPa, close to 0.01-3 GPa for trabecular bone. The total recovery strain ratio and pseudoelastic strain ratio are 8.8% and 2.7%, respectively. It fails mainly by brittle cleavage with the fan-shaped and smooth cleaved facets. Although, local ductile fracture by a few dimples and a small amount of transcrystalline fracture with the cleavage of similarly oriented laths in a colony are observed on the fracture surface. The impedance spectrum of porous Ti-Nb-Ta-Zr has the characteristics of half capacitive arc resistance, showing good corrosion resistance in SBF solution.

Biofunctional magnesium coated Ti6Al4V scaffold enhances osteogenesis and angiogenesis in vitro and in vivo for orthopedic application.

The insufficient osteogenesis and osseointegration of porous titanium based scaffold limit its further application. Early angiogenesis is important for scaffold survival. It is necessary to develop a multifunctional surface on titanium scaffold with both osteogenic and angiogenic properties. In this study, a biofunctional magnesium coating is deposited on porous Ti6Al4V scaffold. For osseointegration and osteogenesis analysis, in vitro studies reveal that magnesium-coated Ti6Al4V co-culture with MC3T3-E1 cells can improve cell proliferation, adhesion, extracellular matrix (ECM) mineralization and ALP activity compared with bare Ti6Al4V cocultivation. Additionally, MC3T3-E1 cells cultured with magnesium-coated Ti6Al4V show significantly higher osteogenesis-related genes expression. In vivo studies including fluorochrome labeling, micro-computerized tomography and histological examination of magnesium-coated Ti6Al4V scaffold reveal that new bone regeneration is significantly increased in rabbits after implantation. For angiogenesis studies, magnesium-coated Ti6Al4V improve HUVECs proliferation, adhesion, tube formation, wound-healing and Transwell abilities. HUVECs cultured with magnesium-coated Ti6Al4V display significantly higher angiogenesis-related genes (HIF-1α and VEGF) expression. Microangiography analysis reveal that magnesium-coated Ti6Al4V scaffold can significantly enhance the blood vessel formation. This study enlarges the application scope of magnesium and provides an optional choice to the conventional porous Ti6Al4V scaffold with enhanced osteogenesis and angiogenesis for further orthopedic applications.

Multifunctional Properties of Quercitrin-Coated Porous Ti-6Al-4V Implants for Orthopaedic Applications Assessed In Vitro.

(1) One strategy to improve the outcome of orthopedic implants is to use porous implants with the addition of a coating with an antibacterial biomolecule. In this study, we aimed to produce and test the biocompatibility, the osteopromotive (both under normal conditions and under a bacterial challenge with lipopolysaccharide (LPS)) and antibacterial activities of a porous Ti-6Al-4V implant coated with the flavonoid quercitrin in vitro. (2) Porous Ti-6Al-4V implants were produced by 3D printing and further functionalized with quercitrin by wet chemistry. Implants were characterized in terms of porosity and mechanical testing, and the coating with quercitrin by fluorescence staining. Implant biocompatibility and bioactivity was tested using MC3T3-E1 preosteoblasts by analyzing cytotoxicity, cell adhesion, osteocalcin production, and alkaline phosphatase (ALP) activity under control and under bacterial challenging conditions using lipopolysaccharide (LPS). Finally, the antibacterial properties of the implants were studied using Staphylococcus epidermidis by measuring bacterial viability and adhesion. (3) Porous implants showed pore size of about 500 µm and a porosity of 52%. The coating was homogeneous over all the 3D surface and did not alter the mechanical properties of the Young modulus. Quercitrin-coated implants showed higher biocompatibility, cell adhesion, and osteocalcin production compared with control implants. Moreover, higher ALP activity was observed for the quercitrin group under both normal and bacterial challenging conditions. Finally, S. epidermidis live/dead ratio and adhesion after 4 h of incubation was lower on quercitrin implants compared with the control. (4) Quercitrin-functionalized porous Ti-6Al-4V implants present a great potential as an orthopedic porous implant that decreases bacterial adhesion and viability while promoting bone cell growth and differentiation.

Biological Effects of a Three-Dimensionally Printed Ti6Al4V Scaffold Coated with Piezoelectric BaTiO3 Nanoparticles on Bone Formation.

Bone defect repair at load-bearing sites is a challenging clinical problem for orthopedists. Defect reconstruction with implants is the most common treatment; however, it requires the implant to have good mechanical properties and the capacity to promote bone formation. In recent years, the piezoelectric effect, in which electrical activity can be generated due to mechanical deformation, of native bone, which promotes bone formation, has been increasingly valued. Therefore, implants with piezoelectric effects have also attracted great attention from orthopedists. In this study, we developed a bioactive composite scaffold consisting of BaTiO3, a piezoelectric ceramic material, coated on porous Ti6Al4V. This composite scaffold showed not only appropriate mechanical properties, sufficient bone and blood vessel ingrowth space, and a suitable material surface topography but also a reconstructed electromagnetic microenvironment. The osteoconductive and osteoinductive properties of the scaffold were reflected by the proliferation, migration, and osteogenic differentiation of mesenchymal stem cells. The ability of the scaffold to support vascularization was reflected by the proliferation and migration of human umbilical vein endothelial cells and their secretion of VEGF and PDGF-BB. A well-established sheep spinal fusion model was used to evaluate bony fusion in vivo. Sheep underwent implantation with different scaffolds, and X-ray, micro-computed tomography, van Gieson staining, and elemental energy-dispersive spectroscopy were used to analyze bone formation. Isolated cervical angiography and visualization analysis were used to assess angiogenesis at 4 and 8 months after transplantation. The results of cellular and animal studies showed that the piezoelectric effect could significantly reinforce osteogenesis and angiogenesis. Furthermore, we also discuss the molecular mechanism by which the piezoelectric effect promotes osteogenic differentiation and vascularization. In summary, Ti6Al4V scaffold coated with BaTiO3 is a promising composite biomaterial for repairing bone defects, especially at load-bearing sites, that may have great clinical translation potential.

Electroactive barium titanate coated titanium scaffold improves osteogenesis and osseointegration with low-intensity pulsed ultrasound for large segmental bone defects.

For large segmental bone defects, porous titanium scaffolds have some advantages, however, they lack electrical activity which hinders their further use. In this study, a barium titanate (BaTiO3) piezoelectric ceramic was used to modify the surface of a porous Ti6Al4V scaffold (pTi), which was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and roughness and water contact angle analyses. Low intensity pulsed ultrasound (LIPUS) was applied in vitro and in vivo study. The activity of bone marrow mesenchymal stem cells, including adhesion, proliferation, and gene expression, was significantly superior in the BaTiO3/pTi, pTi + LIPUS, and BaTiO3/pTi + LIPUS groups than in the pTi group. The activity was also higher in the BaTiO3/pTi + LIPUS group than in the BaTiO3/pTi and pTi + LIPUS groups. Additionally, micro-computed tomography, the mineral apposition rate, histomorphology, and the peak pull-out load showed that these scaffold conditions significantly enhanced osteogenesis and osseointegration 6 and 12 weeks after implantation in large segmental bone defects in the radius of rabbits compared with those resulting from the pTi condition. Consequently, the improved osteogenesis and osseointegration make the BaTiO3/pTi + LIPUS a promising method to promote bone regeneration in large segmental bone defects for clinical application.

Fabrication of Ti + Mg composites by three-dimensional printing of porous Ti and subsequent pressureless infiltration of biodegradable Mg.

A semi-degradable Ti + Mg composite with superior compression and cytotoxicity properties have been successfully fabricated using ink jet 3D printing followed by capillary mediated pressureless infiltration technique targeting orthopaedic implant applications. The composite exhibited low modulus (~5.2 GPa) and high ultimate compressive strength (~418 MPa) properties matching that of the human cortical bone. Ti + Mg composites with stronger 3D interconnected open-porous Ti networks are possible to be fabricated via 3D printing. Corrosion rate of samples measured through immersion testing using 0.9%NaCl solution at 37 °C indicate almost negligible corrosion rate for porous Ti (~1.14 µm/year) and <1 mm/year for Ti + Mg composites for 5 days of immersion, respectively. The composite significantly increased the SAOS-2 osteoblastic bone cell proliferation rate when compared to the 3D printed porous Ti samples and the increase is attributed to the exogenous Mg2+ ions originating from the Ti + Mg samples. The cell viability results indicated absent to mild cytotoxicity. An attempt is made to discuss the key considerations for net-shape fabrication of Ti + Mg implants using ink jet 3D printing followed by infiltration approach.

Influence of macroporosity on NIH/3T3 adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 over bio-functionalized highly porous titanium implant material.

Highly porous Ti implant materials are being used in order to overcome the stress shielding effect on orthopedic implants. However, the lack of bioactivity on Ti surfaces is still a major concern regarding the osseointegration process. It is known that the rapid recruitment of osteoblasts in bone defects is an essential prerequisite for efficient bone repair. Conventionally, osteoblast recruitment to bone defects and subsequent bone repair has been achieved using growth factors. Thus, in this study highly porous Ti samples were processed by powder metallurgy using space holder technique followed by the bio-functionalization through microarc oxidation using a Ca- and P-rich electrolyte. The biological response in terms of early cell response, namely, adhesion, spreading, viability, and proliferation of the novel biofunctionalized highly porous Ti was carried out with NIH/3T3 fibroblasts and MC3T3-E1 preosteoblasts in terms of viability, adhesion, proliferation, and alkaline phosphatase activity. Results showed that bio-functionalization did not affect the cell viability. However, bio-functionalized highly porous Ti (22% porosity) enhanced the cell proliferation and activity. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 73-85, 2019.

Simulated body fluid and the novel bioactive materials derived from it.

Professor Larry Hench first reported that certain glasses are able to spontaneously bond to living bone in 1970. This discovery stimulated research into new kinds of bone-bonding materials. However, there were no guiding principles for this purpose, and many animals were sacrificed in the effort to establish them. The present authors proposed in 1991 that the bone-bonding capacity of a material could be evaluated by examining apatite formation on its surface in an acellular simulated body fluid (SBF), without the need of performing any animal experiments. Various kinds of novel bone-bonding bioactive materials based on Ti metal and its alloys with a number of different functions have been developed using SBF. Some of these have entered clinical use as important bone-repairing materials. Without the method of SBF evaluation, these novel materials would not have been developed. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 968-977, 2019.

Effects of Mo contents on the microstructure, properties and cytocompatibility of the microwave sintered porous Ti-Mo alloys.

The porous Ti-Mo alloys were prepared by microwave sintering, and the effects of Mo contents on the pore structure, phase composition, compressive strength, elastic modulus, bending strength, corrosion resistance and cytocompatibility of porous Ti-Mo alloys were investigated. The results show that the porous Ti-Mo alloys are composed of α phase and ß phase, and the volume fraction of ß phase increases with increasing the Mo contents. The amount of Kirkendall pores distributed over the porous Ti-Mo alloys skeleton increases with increasing the Mo contents, which greatly increases the porosities and pore sizes of the porous Ti-Mo alloys. Correspondingly, all of the compressive strength, elastic modulus and bending strength of the porous Ti-Mo alloys decrease with increasing the Mo contents. The porous Ti-Mo alloys present excellent corrosion resistance in the Hank's solution due to the oxidation film of TiO2, MoO2 and MoO3 naturally formed on the surface, and the Mo contents have no obvious effect on the corrosion resistance. The cell viabilities of the porous Ti-Mo alloys are higher than 94%, indicating the porous Ti-Mo alloys possess favorable cytocompatibility. Moreover, the porous Ti-Mo alloys are beneficial to the spread, proliferation and differentiation of osteoblast-like cells, and the Mo contents have no significant effect on the cytocompatibility of the porous Ti-Mo alloys.

In vitro and in vivo comparisons of the porous Ti6Al4V alloys fabricated by the selective laser melting technique and a new sintering technique.

A new sintering technique using Ti6Al4V powder suspension was performed to prepare porous Ti6Al4V alloy with 75% porosity. Porous Ti6Al4V alloy with the same porosity fabricated by selective laser melting technique was used as the control. The characteristics, mechanical and biological properties of the two types of porous Ti6Al4V alloys were evaluated by mechanical tests, in vitro cell analysis and implantations. Results indicated that both groups showed good biocompatibility and osteogenic ability. However, microstructure and mechanical properties of the sintered porous Ti6Al4V were more similar to the cancellous bone without obvious stress shielding, and the new type of sample may be more effective in achieving early stability after implantation. Therefore, under the study conditions, this new type of porous alloy prospects a good candidate for biomaterials, especially for repairing bone defects and arthroplasty in orthopedics.

Three-Dimensional Porous Ti3C2Tx-NiO Composite Electrodes with Enhanced Electrochemical Performance for Supercapacitors.

Ti3C2Tx and Ti3C2Tx-NiO composites with three-dimensional (3D) porous networks were successfully fabricated via vacuum freeze-drying. The microstructure, absorption, and electrochemical properties of the developed composites were investigated. Nickel oxide (NiO) nanoparticles could be evenly distributed on the three-dimensional network of three-dimensional Ti3C2Tx using solution processing. When employed as electrochemical capacitor electrodes in 1 M environmentally friendly sodium sulfate, Na2SO4, solution, the three-dimensional porous Ti3C2Tx-NiO composite electrodes exhibited considerable volume specific capacitance as compared to three-dimensional porous Ti3C2Tx. The three-dimensional porous Ti3C2Tx-NiO composite delivered a remarkable cycling performance with a capacitance retention of up to 114% over 2500 cycles. The growth trend of the capacitance with NiO content shows that nickel oxide plays a crucial role in the composite electrodes. These results present a roadmap for the development of convenient and economical supercapacitors in consideration with the possibilities of morphological control and the extensibility of the process.

Study of Bone Regeneration and Osteointegration Effect of a Novel Selective Laser-Melted Titanium-Tantalum-Niobium-Zirconium Alloy Scaffold.

Titanium-tantalum-niobium-zirconium (Ti-Ta-Nb-Zr) alloy is a novel material currently available for orthopedic applications. However, these scaffolds, manufactured using traditional methods, present disadvantages such as irregular pore size, unsuitable mechanical features, and poor connectivity between pores. In this study, porous Ti-Ta-Nb-Zr (60% Ti, 2% Ta, 36% Nb, and 2% Zr) scaffolds were printed by selective laser melting (SLM) with a controllable pore size of 300-400 µm. The mechanical properties of the SLM-manufactured scaffolds were evaluated, as well as its osteogenesis in vitro and osteointegration in vivo. Porous Ti-Ta-Nb-Zr scaffolds yielded superior cell proliferation and cell adhesion results with human bone mesenchymal stem cells (hBMSCs) compared with porous Ti6Al4V scaffolds. The osteogenic differentiation experiment demonstrated enhanced osteogenic differentiation of hBMSCs in the Ti-Ta-Nb-Zr group than in the Ti6Al4V group. After the porous Ti-Ta-Nb-Zr or control scaffolds were implanted into a cylindrical bone defect in the rabbit lateral femoral condyle, the initial radiological results confirmed the excellent osteogenic activity of the novel 3D-printed scaffolds. Histological analysis further indicated that the Ti-Ta-Nb-Zr scaffolds promoted bone regeneration and osteointegration more effectively than Ti6Al4V scaffolds. Our findings demonstrate that the SLM-manufactured porous Ti-Ta-Nb-Zr scaffold has considerable potential for clinical orthopedic application.

Bionic mechanical design and 3D printing of novel porous Ti6Al4V implants for biomedical applications.

In maxillofacial surgery, there is a significant need for the design and fabrication of porous scaffolds with customizable bionic structures and mechanical properties suitable for bone tissue engineering. In this paper, we characterize the porous Ti6Al4V implant, which is one of the most promising and attractive biomedical applications due to the similarity of its modulus to human bones. We describe the mechanical properties of this implant, which we suggest is capable of providing important biological functions for bone tissue regeneration. We characterize a novel bionic design and fabrication process for porous implants. A design concept of "reducing dimensions and designing layer by layer" was used to construct layered slice and rod-connected mesh structure (LSRCMS) implants. Porous LSRCMS implants with different parameters and porosities were fabricated by selective laser melting (SLM). Printed samples were evaluated by microstructure characterization, specific mechanical properties were analyzed by mechanical tests, and finite element analysis was used to digitally calculate the stress characteristics of the LSRCMS under loading forces. Our results show that the samples fabricated by SLM had good structure printing quality with reasonable pore sizes. The porosity, pore size, and strut thickness of manufactured samples ranged from (60.95± 0.27)% to (81.23±0.32)%, (480±28) to (685±31) µm, and (263±28) to (265±28) µm, respectively. The compression results show that the Young's modulus and the yield strength ranged from (2.23±0.03) to (6.36±0.06) GPa and (21.36±0.42) to (122.85±3.85) MPa, respectively. We also show that the Young's modulus and yield strength of the LSRCMS samples can be predicted by the Gibson-Ashby model. Further, we prove the structural stability of our novel design by finite element analysis. Our results illustrate that our novel SLM-fabricated porous Ti6Al4V scaffolds based on an LSRCMS are a promising material for bone implants, and are potentially applicable to the field of bone defect repair.