Porous Ti Scaffolds Research Articles

Potential assessment in laser powder bed fusion of bionic porous Ti scaffolds concerning compressive behavior, porosity, and surface roughness

The fabrication of cellular structures with biocompatible materials for implants has increased in recent years because of human aging and traffic road accidents. Laser powder bed fusion or Selective laser melting (SLM) can fabricate various load-bearing implants with mass customization in design and manufacturing. This work involves a manufacturability study in selective laser melting of biomedical Ti alloy implant plug for Osteoarthritis patients. The investigation involved the control variables like laser power (175,185,195) watt, scanning speed (1100,1250,1400) mm/s, and hatch spacing (0.065,0.0725,0.08) mm alongwith output responses such as Compressive yield strength, Elastic modulus, porosity, and surface roughness. The experiments were performed using Box Behnken design in Response surface modelling for collaborative optimization. The results were explicitly explained with an in-depth process physics supported with Characterization involving Scanning electron microscopy, Electro-dispersive spectroscopy, X-ray diffraction, micro-computed tomography, optical profilometry analyses, and process schematics. The optimal setting with laser power (195 W), scanning speed (1100 mm/s), and hatch spacing (0.068 mm) yielded high compressive yield strength (22.41 MPa), near trabecular bone Elastic modulus (0.891GPa), controlled porosity formation (29.32 %), and optimal surface roughness (3.647 μm). Topography resulted in a prominent lack of fusion pores because of low energy density levels, whereas the optimal settings produced around 15 % improvement from design of experiments data.

Effect of Interbody Implants on the Biomechanical Behavior of Lateral Lumbar Interbody Fusion: A Finite Element Study

Porous titanium interbody scaffolds are growing in popularity due to their appealing advantages for bone ingrowth. This study aimed to investigate the biomechanical effects of scaffold materials in both normal and osteoporotic lumbar spines using a finite element (FE) model. Four scaffold materials were compared: Ti6Al4V (Ti), PEEK, porous titanium of 65% porosity (P65), and porous titanium of 80% porosity (P80). In addition, the range of motion (ROM), endplate stress, scaffold stress, and pedicle screw stress were calculated and compared. The results showed that the ROM decreased by more than 96% after surgery, and the solid Ti scaffold provided the lowest ROM (1.2-3.4% of the intact case) at the surgical segment among all models. Compared to solid Ti, PEEK decreased the scaffold stress by 53-66 and the endplate stress by 0-33%, while porous Ti decreased the scaffold stress by 20-32% and the endplate stress by 0-32%. Further, compared with P65, P80 slightly increased the ROM (<0.03°) and pedicle screw stress (<4%) and decreased the endplate stress by 0-13% and scaffold stress by approximately 18%. Moreover, the osteoporotic lumbar spine provided higher ROMs, endplate stresses, scaffold stresses, and pedicle screw stresses in all motion modes. The porous Ti scaffolds may offer an alternative for lateral lumbar interbody fusion.

Functionalized 3D-printed porous titanium scaffold induces in situ vascularized bone regeneration by orchestrating bone microenvironment

Titanium (Ti) and its alloys have been extensively explored for treating load-bearing bone defects. However, high-stress shielding, weak osteogenic activity, and insufficient vascularization remain key challenges for the long-term clinical outcomes of Ti-based implants. Herein, inspired by structural and functional cues of bone regeneration, a silicon-doped nano-hydroxyapatite (nSiHA)/titanium dioxide (TiO2) composite coating with a hierarchical micro/nano-network structure is constructed on the surface of a 3D-printed porous Ti scaffold via a combined strategy of acid-alkali (AA) treatment and electrochemical deposition technique, which not only endows the scaffold with excellent osteoinduction ability but can also effectively immobilize and release vascular endothelial growth factor (VEGF). The results of the in vitro cell experiments show that the functionalized Ti scaffold significantly promotes osteogenesis in bone marrow mesenchymal stem cells (BMSCs) and angiogenesis in human umbilical vein endothelial cells (HUVECs) by activating the extracellular signal-regulated protein kinase (ERK) and HIF-1α signaling pathways. After being implanted into a rat femoral condyle defect model, the functionalized Ti scaffold can induce in situ vascularized bone regeneration by orchestrating the two coupled processes of angiogenesis and osteogenesis. These findings indicate that the functionalized Ti scaffold has great potential in bone tissue regeneration and is a promising candidate for load-bearing bone defect repair.

Combined Effects of Polydopamine-Assisted Copper Immobilization on 3D-Printed Porous Ti6Al4V Scaffold for Angiogenic and Osteogenic Bone Regeneration

Numerous studies have demonstrated that biological compounds and trace elements such as dopamine (DA) and copper ions (Cu) could be modified onto the surfaces of scaffolds using a one-step immersion process which is simple, inexpensive and, most importantly, non-cytotoxic. The development and emergence of 3D printing technologies such as selective laser melting (SLM) have also made it possible for us to fabricate bone scaffolds with precise structural designs using metallic compounds. In this study, we fabricated porous titanium scaffolds (Ti) using SLM and modified the surface of Ti with polydopamine (PDA) and Cu. There are currently no other reported studies with such a combination for osteogenic and angiogenic-related applications. Results showed that such modifications did not affect general appearances and microstructural characteristics of the porous Ti scaffolds. This one-step immersion modification allowed us to modify the surfaces of Ti with different concentrations of Cu ions, thus allowing us to fabricate individualized scaffolds for different clinical scenarios. The modification improved the hydrophilicity and surface roughness of the scaffolds, which in turn led to promote cell behaviors of Wharton’s jelly mesenchymal stem cells. Ti itself has high mechanical strength, therefore making it suitable for surgical handling and clinical applications. Furthermore, the scaffolds were able to release ions in a sustained manner which led to an upregulation of osteogenic-related proteins (bone alkaline phosphatase, bone sialoprotein and osteocalcin) and angiogenic-related proteins (vascular endothelial growth factor and angiopoietin-1). By combining additive manufacturing, Ti6Al4V scaffolds, surface modification and Cu ions, the novel hybrid 3D-printed porous scaffold could be fabricated with ease and specifically benefited future bone regeneration in the clinic.

On-Growth and In-Growth Osseointegration Enhancement in PM Porous Ti-Scaffolds by Two Different Bioactivation Strategies: Alkali Thermochemical Treatment and RGD Peptide Coating.

A lack of primary stability and osteointegration in metallic implants may result in implant loosening and failure. Adding porosity to metallic implants reduces the stress shielding effect and improves implant performance, allowing the surrounding bone tissue to grow into the scaffold. However, a bioactive surface is needed to stimulate implant osteointegration and improve mechanical stability. In this study, porous titanium implants were produced via powder sintering to create different porous diameters and open interconnectivity. Two strategies were used to generate a bioactive surface on the metallic foams: (1) an inorganic alkali thermochemical treatment, (2) grafting a cell adhesive tripeptide (RGD). RGD peptides exhibit an affinity for integrins expressed by osteoblasts, and have been reported to improve osteoblast adhesion, whereas the thermochemical treatment is known to improve titanium implant osseointegration upon implantation. Bioactivated scaffolds and control samples were implanted into the tibiae of rabbits to analyze the effect of these two strategies in vivo regarding bone tissue regeneration through interconnected porosity. Histomorphometric evaluation was performed at 4 and 12 weeks after implantation. Bone-to-implant contact (BIC) and bone in-growth and on-growth were evaluated in different regions of interest (ROIs) inside and outside the implant. The results of this study show that after a long-term postoperative period, the RGD-coated samples presented higher quantification values of quantified newly formed bone tissue in the implant’s outer area. However, the total analyzed bone in-growth was observed to be slightly greater in the scaffolds treated with alkali thermochemical treatment. These results suggest that both strategies contribute to enhancing porous metallic implant stability and osteointegration, and a combination of both strategies might be worth pursuing.

A Novel Design of Temporomandibular Joint Prosthesis for Lateral Pterygoid Muscle Attachment: A Preliminary Study.

Introduction: In temporomandibular joint (TMJ) replacement operation, due to the condylectomy, the lateral pterygoid muscle (LPM) lost attachment and had impact on the mandible kinematic function. This study aimed to design a novel TMJ replacement prosthesis for LPM attachment and to verify its feasibility by preliminary in vitro and in vivo experiments.Materials and Methods: An artificial TMJ prosthesis designed with a porous structure on the condylar neck region for LPM attachment was fabricated by a 3D printed titanium (Ti) alloy. A rat myoblast cell line (L6) was tested for adhesion and biocompatibility with porous titanium scaffolds in vitro by cell counting Kit-8 (CCK-8), scanning electron microscope (SEM), flow cytometry (FCM), real-time quantitative polymerase chain reaction (RT-qPCR), immunocytofluorescense, western blotting, etc. The porous titanium scaffolds were further embedded in the rat intervertebral muscle to analyze muscle growth and biomechanical strength in vivo. The novel artificial TMJ prosthesis was implanted to reconstruct the goat's condyle and LPM reattachment was analyzed by hard tissue section and avulsion force test.Results: L6 muscle cells showed good proliferation potential on the porous Ti scaffold under SEM scanning and FCM test. In RT-qPCR, immunocytofluorescense and western blotting tests, the L6 cell lines had good myogenic capacity when cultured on the scaffold with high expression of factors such as Myod1 and myoglobin, etc. In the in vivo experiment, muscles penetrated into the porous scaffold in both rats and goats. In rat's intervertebral muscle implantation, the avulsion force was 0.716 N/mm2 in 4 weeks after operation and was significantly increased to 0.801 N/mm2 at 8 weeks (p < 0.05). In goat condylar reconstruction with the porous scaffold prosthesis, muscles attached to the prosthesis with the avulsion force of 0.436 N/mm2 at 8 weeks, but was smaller than the biological muscle-bone attachment force.Conclusion: The novel designed TMJ prosthesis can help LPM attach to its porous titanium scaffold structure area for future function.

Bio-surface coated titanium scaffolds with cancellous bone-like biomimetic structure for enhanced bone tissue regeneration

In view of the fact that titanium (Ti)-based implants still face the problem of loosening and failure of the implants caused by the slow biological response, the low osseointegration rate and the implant bacterial infection in clinical application, we designed a cancellous bone-like biomimetic Ti scaffold using the template accumulated by sugar spheres as a pore-forming agent. And based on a modified surface mineralization process and mussel-like adhesion mechanism, a silicon-doped calcium phosphate composite coating (Van-pBNPs/pep@pSiCaP) with Vancomycin (Van)-loaded polydopamine (pDA)-modified albumin nanoparticles (Van-pBNPs) and cell adhesion peptides (GFOGER) was constructed on the surface of Ti scaffold for mimicking the extracellular matrix (ECM) microenvironment of natural bone matrix to induce greater tissue regeneration. The in vitro study demonstrated that this porous Ti scaffold with functional bio-surface could distinctly facilitate cell early adhesion and spreading, and activate the expression of α2β1 integrin receptor on the cell membrane through promoting the formation of focal adhesions (FAs) in bone marrow stromal cells (BMSCs), thus mediating greater osteogenic cell differentiation. And it could also effectively inhibit the adhesion and growth of Staphylococcus epidermidis, exhibiting good antibacterial properties. Moreover, the Van-pBNPs/pep@pSiCaP-Ti scaffolds showed enhanced in vivo bone-forming ability due to the contributions of bioactive chemical components and the natural cancellous bone-like macrostructure. This work offers a promising structural and functional bio-inspired strategy for designing metal implants with desirable ability of osteoinduction synergistically with antibacterial efficacy for promoting bone regeneration and infection prevention simultaneously. Statement of significanceThis manuscript describes a new method for making porous Ti scaffolds with a natural cancellous bone-like structure. Besides, a functional bio-surface was constructed on the bionic structure, mimicking some of the functions of the collagen-rich organic matrix and inorganic CaP nanocrystallites of native ECM of bone in chemical components and biological activities. This interconnected inter-pore opening structure encouraged the migration of cells among open macro-pores within the scaffold. In addition, the functionalized surface not only improved early cell adhesion, spreading, stimulated greater osteogenic differentiation of bone-forming cells, but also endowed the scaffold with excellent antibacterial effect. The biomimetic metal implant with multiple biomedical functions designed in this study has a great clinical application potential. This study represents a feasible method for the preparation of biomimetic structure of metal implants and the improvement of their surface biological activity.

Bifunctional Bio-Surface Decorated Bone-Grafting Titanium Material with Cancellous Bone-Like Biomimetic Structure for Enhanced Bone Tissue Regeneration

In view of the fact that titanium (Ti)-based implants still face the problem of loosening and failure of the implants caused by the slow biological response, the low osseointegration rate and the implant bacterial infection in clinical application, we designed a cancellous bone-like biomimetic Ti scaffold via using the template accumulated by sugar spheres as pore-forming agent. And based on a modified surface mineralization process and mussel-like adhesion mechanism, a silicon-doped calcium phosphate composite coating (Van-pBNPs/pep@pSiCaP) with Vancomycin (Van)-loaded polydopamine (pDA)-modified albumin nanoparticles (Van-pBNPs) and cell adhesion peptides (GFOGER) was constructed on the surface of Ti scaffold for mimicking the extracellular matrix (ECM) microenvironment of natural bone matrix to induce greater tissue regeneration. The in vitro study demonstrated that this porous Ti scaffold with functional bio-surface could distinctly facilitate cell early adhesion and spreading, and activate the expression of α2β1 integrin receptor on the cell membrane through promoting the formation of focal adhesions (FAs) in bone marrow stromal cells (BMSCs), thus mediating greater osteogenic cell differentiation. And it could also effectively inhibit the adhesion and growth of Staphylococcus epidermidis, exhibiting excellent antibacterial properties. Moreover, the Van-pBNPs/pep@pSiCaP-Ti scaffolds showed enhanced in vivo bone-forming ability due to the contributions of bioactive chemical components and the natural cancellous bone-like macrostructure. This work offers a promising structural and functional bio-inspired strategy for designing metal implants with desirable ability of osteoinduction synergistically with antibacterial efficacy for promoting bone regeneration and infection prevention simultaneously.

Micromechanical Measurements and Biocompatibility of the High Porosity Ti Scaffold Made with Saccharose as a Space Holder

The paper presents mechanical properties of the porous Ti scaffold made with saccharose as a space holder. The Ti scaffolds had the porosity of 50, 60 and 70% and were made using 100 and 325 mesh Ti as a scaffold material. The pores were established using saccharose spherical space holder particles of 0.7–0.9 mm in diameter. The local mechanical properties of the Ti scaffold have been measured using nanoindenter. Several loading-unloading characteristics of the thin scaffold walls in the microscale have been measured. It has been observed that Ti scaffolds have very high mechanical properties measured in the microscale that are correlated with partial scaffold oxidation and a formation of TiO2, which took place during the production stages. The scaffold is composed mainly of Ti oxide and the structure has been identified by XRD as well as XPS. The highest mechanical properties have scaffolds composed of 100 mesh Ti particles, compared to 325 mesh Ti. The microscale tests measurements are rather slightly affected by the pore presence and are under influence of Ti particles. The MTT test shows slightly higher proliferation of NHost cells on porous Ti scaffold in comparison to the reference Ti sample.

A Mussel-Inspired Persistent ROS-Scavenging, Electroactive, and Osteoinductive Scaffold Based on Electrochemical-Driven In Situ Nanoassembly.

Conductive polymers are promising for bone regeneration because they can regulate cell behavior through electrical stimulation; moreover, they are antioxidative agents that can be used to protect cells and tissues from damage originating from reactive oxygen species (ROS). However, conductive polymers lack affinity to cells and osteoinductivity, which limits their application in tissue engineering. Herein, an electroactive, cell affinitive, persistent ROS-scavenging, and osteoinductive porous Ti scaffold is prepared by the on-surface in situ assembly of a polypyrrole-polydopamine-hydroxyapatite (PPy-PDA-HA) film through a layer-by-layer pulse electrodeposition (LBL-PED) method. During LBL-PED, the PPy-PDA nanoparticles (NPs) and HA NPs are in situ synthesized and uniformly coated on a porous scaffold from inside to outside. PDA is entangled with and doped into PPy to enhance the ROS scavenging rate of the scaffold and realize repeatable, efficient ROS scavenging over a long period of time. HA and electrical stimulation synergistically promote osteogenic cell differentiation on PPy-PDA-HA films. Ultimately, the PPy-PDA-HA porous scaffold provides excellent bone regeneration through the synergistic effects of electroactivity, cell affinity, and antioxidative activity of the PPy-PDA NPs and the osteoinductivity of HA NPs. This study provides a new strategy for functionalizing porous scaffolds that show great promise as implants for tissue regeneration.

Designing bioactive porous titanium interfaces to balance mechanical properties and in vitro cells behavior towards increased osseointegration

Titanium implant failures are mainly related to stress shielding phenomenon and the poor cell interaction with host bone tissue. The development of bioactive and biomimetic Ti scaffolds for bone regeneration remains a challenge which needs the design of Ti implants with enhanced osseointegration. In this context, 4 types of titanium samples were fabricated using conventional powder metallurgy, fully dense, dense etched, porous Ti, and porous etched Ti. Porous samples were manufactured by space holder technique, using ammonium bicarbonate particles as spacer in three different ranges of particle size (100–200 μm, 250–355 μm and 355–500 μm). Substrates were chemically etched by immersion in fluorhydric acid at different times (125 and 625 s) and subsequently, were characterized from a micro-structural, topographical and mechanical point of view. Etched surfaces showed an additional roughness preferentially located inside pores. In vitro tests showed that all substrates were biocompatible (80% of cell viability), confirming cell adhesion of premioblastic cells. Similarly, osteoblast showed similar cell proliferation rates at 4 days, however, higher cell metabolic activity was observed in fully dense and dense etched surfaces at 7 days. In contrast, a significant increase of alkaline phosphatase enzyme expression was observed in porous and porous etched samples compared to control surfaces (dense and dense etched), noticing the suitable surface modification parameters (porosity and roughness) to improve cell differentiation. Furthermore, the presence of pores and rough surfaces of porous Ti substrates remarkably decreased macrophage activation reducing the M1 phenotype polarization as well M1 cell marker expression. Thus, a successful surface modification of porous Ti scaffolds has been performed towards a reduction on stress shielding phenomenon and enhancement of bone osseointegration, achieving a biomechanical and biofunctional equilibrium.

Mechanical behaviors and porosity of porous Ti prepared with large-size acicular urea as spacer

Porous Ti scaffolds with average pore size of 600 µm and porosity ranging from 31.1 to 61.2% were successfully prepared by powder metallurgy technology employing large size acicular urea as space holder. Results indicated that the porosity (P) of porous Ti could be determined accurately by added spacer content (Sc) in the green-pressing because the relationship could be formulated as P = aSc + b, where a and b are constants. The compressive strength and structural stiffness were in the range of 50–332 MPa and 0.6–3.7 GPa, respectively. Moreover, the dependence between relative porosity and relative strength, along with the dependence between relative density and relative Yong’s modulus were formulated. Our research can provide helpful information to fabricate porous Ti with desirable structure and mechanical properties by spacer method.

Evidence for Fast Lithium-Ion Diffusion and Charge-Transfer Reactions in Amorphous TiO x Nanotubes: Insights for High-Rate Electrochemical Energy Storage.

The charge-storage kinetics of amorphous TiO x nanotube electrodes formed by anodizing three-dimensional porous Ti scaffolds are reported. The resultant electrodes demonstrated not only superior storage capacities and rate capability to anatase TiO x nanotube electrodes but also improved areal capacities (324 μAh cm-2 at 50 μA cm-2 and 182 μAh cm-2 at 5 mA cm-2) and cycling stability (over 2000 cycles) over previously reported TiO x nanotube electrodes using planar current collectors. Amorphous TiO x exhibits very different electrochemical storage behavior from its anatase counterpart as the majority of its storage capacity can be attributed to capacitive-like processes with more than 74 and 95% relative contributions being attained at 0.05 and 1 mV s-1, respectively. The kinetic analysis revealed that the insertion/extraction process of Li+ in amorphous TiO x is significantly faster than in anatase structure and controlled by both solid-state diffusion and interfacial charge-transfer kinetics. It is concluded that the large capacitive contribution in amorphous TiO x originates from its highly defective and loosely packed structure and lack of long-range ordering, which facilitate not only a significantly faster Li+ diffusion process (diffusion coefficients of 2 × 10-14 to 3 × 10-13 cm2 s-1) but also more facile interfacial charge-transfer kinetics than anatase TiO x.

The effect of 3D-printed Ti6Al4V scaffolds with various macropore structures on osteointegration and osteogenesis: A biomechanical evaluation

A properly designed porous scaffold can accelerate the osseointegration process, and the use of computer-aided design (CAD) and additive manufacturing (AM) techniques has the potential to improve the traditional porous scaffold approach. In this study, we evaluate the effect of porous Ti6Al4V (Ti) with different pore structures on osteointegration and osteogenesis. Porous Ti scaffolds with different pore structures based on four commercially available implants were designed and manufactured by CAD and selective laser melting (SLM). Micro-CT showed that SLM was able to produce Ti scaffolds with different pore structures. The mechanical properties evaluated by finite element analysis and compression tests indicated that the four porous scaffolds in our study were mechanically adapted, despite their different mechanical properties. Then, we used 3D-printed porous discs to culture human bone marrow mesenchymal stem cells (hBMMSCs), the main seed cells of bone tissue engineering. The results showed no significant difference among the four groups in cell morphology, viability and proliferation. In addition, four groups showed a comparable mineralization ability even though Ti-g had a higher alkaline phosphatase activity (ALP). In vivo tests in a rabbit model showed that all four groups were suitable for new bone ingrowth and integration. These findings indicate that the four different pore structures in the Ti scaffolds provided good osteointegration and osteogenesis.

糖球造孔法制备三维多孔钛支架及性能表征

糖球造孔法制备三维多孔钛支架及性能表征

Dual properties of zirconia coated porous titanium for a stiffness enhanced bio-scaffold

Porous titanium (Ti)-based scaffolds are a promising approach for achieving stiffness reduction. To be used as a biomaterial, porous Ti scaffolds (P-Ti) must have suitable wear and corrosion resistance and the generation of either metallic wear debris or Ti ion release should be insignificant throughout a large timescale. The present study combines a porous structure appropriate for cell ingrowth with a physically and chemically stable thin-film coating to create a load-bearing bio-inspired scaffold. The as-designed zirconia-coated P-Ti (Z-P-Ti) was made via a hydrothermal process, followed by a sol-gel method. Mechanical tests were conducted primarily on P-Ti, and chemical stability tests were conducted on Z-P-Ti. The biocompatibility test results correlated with cell mitigation into Z-P-Ti were compared with those for reference surfaces. The results show that Z-P-Ti is load-bearable with an increased surface hardness and roughness. 3T3 cell morphology and viability assessed using the live/dead cell staining protocol show a significant enhancement of cell affinity on the surface of Z-P-Ti. The combination of porous Ti, a load-bearable structure, and biocompatible zirconia coating makes the designed biomaterial promising for many applications, such as vertebral discs.

Construction of surface HA/TiO2 coating on porous titanium scaffolds and its preliminary biological evaluation

A simple approach to fabricating hydroxyxapatite/titanium dioxide (HA/TiO2) coating on porous titanium (Ti) scaffolds was developed in the present study. Surface TiO2 layer was firstly formed on porous Ti scaffolds with multi-scale pores by acid-alkali (AA) treatment. The outer HA layer was then formed on the TiO2 layer by subsequent pulse electrochemical deposition (ED) technique. All the three main process parameters, i.e. deposition times, current density and mass transfer mode affected the properties of the HA coating notably. Under the conditions of 90 deposition cycles, −10mA/cm2 of pulse current density and stirring, a thin layer of homogeneous and nanorod-like HA sediments was formed on the substrate surface of porous Ti scaffolds. The results of protein adsorption and cellular experiments showed that compared to the single TiO2 surface, the HA/TiO2 surface allowed more adsorption of serum proteins and further enhanced the alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts.

Ti scaffolds with tailored porosities and mechanical properties using porous polymer templates

This study proposes a simple, useful approach to produce three-dimensionally macrochanneled titanium (Ti) scaffolds with tailored porosities and mechanical properties using porous polylactic acid (PLA) templates that can be prepared by conventional solid freeform fabrication (SFF) technique. Specifically, methylcellulose (MC) polymer was used as a binder since it could effectively bind coarse Ti particles and remain chemically stable inert in organic solvents used to dissolve PLA polymer. A Ti slurry-filled PLA was immersed in chloroform to remove the PLA template, followed by sintering at 1300°C for 3h in a vacuum. The use of a relatively small amount of a MC binder and removal of the PLA template in solvent enabled the construction of straight Ti frameworks and macrochannels in a 3-D periodic pattern without severe impurity contamination. This tightly controlled porous structure enabled the achievement of high compressive strengths without a catastrophic failure, while the compressive strength increased from ~72MPa to 121MPa with a decrease in overall porosity from ~75vol% to ~67vol%. In addition, the porous Ti scaffolds showed good biocompatibility, which was assessed by in vitro cell tests in terms of attachment, proliferation, and differentiation of MC3T3-E1 cells.

Rapid direct deposition of TiH2 paste for porous Ti scaffolds with tailored porous structures and mechanical properties

We herein demonstrate the utility of the rapid direct deposition of a titanium hydride (TiH2) paste for the production of porous titanium (Ti) scaffolds with tailored porous structures and mechanical properties. In particular, methylcellulous (MC) polymer was used as the binder, since it can rapidly solidify in acetone through solvent extraction, thus enabling deposited green filaments to have high structural integrity. In addition, TiH2 powder was used as the Ti source because of its smaller particle size than commercial Ti powder and conversion to Ti metal through a two-step dehydrogenation process. The uses of fine TiH2 powder and MC binder allowed for the creation of three−dimensionally interconnected periodic macrochannels with sizes of ∼165 ± 14 × 167 ± 25 μm. The produced Ti scaffold had a porosity of ∼42 ± 7 vol % and a reasonably high compressive strength of 48 ± 15 MPa. In addition, the porosity and mechanical properties of porous Ti scaffolds could be tailored simply by adjusting the initial distances between deposited green TiH2/MC filaments. All of the porous Ti scaffolds produced with various porosities showed good in vitro biocompatibility.

An improved polymeric sponge replication method for biomedical porous titanium scaffolds

Biomedical porous titanium (Ti) scaffolds were fabricated by an improved polymeric sponge replication method. The unique formulations and distinct processing techniques, i.e. a mixture of water and ethanol as solvent, multiple coatings with different viscosities of the Ti slurries and centrifugation for removing the extra slurries were used in the present study. The optimized porous Ti scaffolds had uniform porous structure and completely interconnected macropores (~365.1μm). In addition, two different sizes of micropores (~45.4 and ~6.2μm) were also formed in the skeleton of the scaffold. The addition of ethanol to the Ti slurry increased the compressive strength of the scaffold by improving the compactness of the skeleton. A compressive strength of 83.6±4.0MPa was achieved for a porous Ti scaffold with a porosity of 66.4±1.8%. Our cellular study also revealed that the scaffolds could support the growth and proliferation of mesenchymal stem cells (MSCs).