Mechanical Properties and In Vitro Behavior of Additively Manufactured and Functionally Graded Ti6Al4V Porous Scaffolds

Bone tissue engineering is an advanced field for treatment of fractured bones to restore/regulate biological functions. Biopolymeric/bioceramic-based hybrid nanocomposite scaffolds are potential biomaterials for bone tissue because of biodegradable and biocompatible characteristics. We report synthesis of nanocomposite based on acrylic acid (AAc)/guar gum (GG), nano-hydroxyapatite (HAp NPs), titanium nanoparticles (TiO2 NPs), and optimum graphene oxide (GO) amount via free radical polymerization method. Porous scaffolds were fabricated through freeze-drying technique and coated with silver sulphadiazine. Different techniques were used to investigate functional group, crystal structural properties, morphology/elemental properties, porosity, and mechanical properties of fabricated scaffolds. Results show that increasing amount of TiO2 in combination with optimized GO has improved physicochemical and microstructural properties, mechanical properties (compressive strength (2.96 to 13.31 MPa) and Young’s modulus (39.56 to 300.81 MPa)), and porous properties (pore size (256.11 to 107.42 μm) and porosity (79.97 to 44.32%)). After 150 min, silver sulfadiazine release was found to be ~94.1%. In vitro assay of scaffolds also exhibited promising results against mouse pre-osteoblast (MC3T3-E1) cell lines. Hence, these fabricated scaffolds would be potential biomaterials for bone tissue engineering in biomedical engineering.

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Porous Calcium Phosphate Ceramic Scaffolds with Tailored Pore Orientations and Mechanical Properties Using Lithography-Based Ceramic 3D Printing Technique

Materials ◽

10.3390/ma11091711 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1711 ◽

Cited By ~ 11

Author(s):

Jung-Bin Lee ◽

Woo-Youl Maeng ◽

Young-Hag Koh ◽

Hyoun-Ee Kim

Keyword(s):

Mechanical Properties ◽

Calcium Phosphate ◽

Processing Parameters ◽

Solid Loading ◽

Periodic Pattern ◽

Regeneration Ability ◽

Porous Scaffolds ◽

Printing Technique ◽

Sbf Solution

This study demonstrates the usefulness of the lithography-based ceramic 3-dimensional printing technique with a specifically designed top-down process for the production of porous calcium phosphate (CaP) ceramic scaffolds with tailored pore orientations and mechanical properties. The processing parameters including the preparation of a photocurable CaP slurry with a high solid loading (φ = 45 vol%), the exposure time for photocuring process, and the initial designs of the porous scaffolds were carefully controlled. Three types of porous CaP scaffolds with different pore orientations (i.e., 0°/90°, 0°/45°/90°/135°, and 0°/30°/60°/90°/120°/150°) were produced. All the scaffolds exhibited a tightly controlled porous structure with straight CaP frameworks arranged in a periodic pattern while the porosity was kept constant. The porous CaP scaffold with a pore orientation of 0°/90° demonstrated the highest compressive strength and modulus due to a number of CaP frameworks parallel to the loading direction. On the other hand, scaffolds with multiple pore orientations may exhibit more isotropic mechanical properties regardless of the loading directions. The porous CaP scaffolds exhibited an excellent in vitro apatite-forming ability in a stimulated body fluid (SBF) solution. These findings suggest that porous CaP scaffolds with tailored pore orientations may provide tunable mechanical properties with good bone regeneration ability.

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Porous polymeric scaffolds for bone regeneration

e-Polymers ◽

10.1515/epoly.2005.5.1.110 ◽

2005 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

Katarzyna Filipczak ◽

Ireneusz Janik ◽

Marek Kozicki ◽

Piotr Ulanski ◽

Janusz M. Rosiak ◽

...

Keyword(s):

Mechanical Properties ◽

Total Porosity ◽

Polymer Chains ◽

Porous Scaffolds ◽

Solvent Casting ◽

Polymeric Scaffolds ◽

Good Biocompatibility ◽

Particulate Leaching ◽

Highly Porous

AbstractSolvent casting/particulate leaching has been used to synthesize highly porous polymeric scaffolds of controlled pore size, based on poly(methyl methacrylate) (PMMA) and poly(ε-caprolactone) (PCL). Obtained structures have a total porosity of c. 60%, with good interconnections between the pores. Porous scaffolds prepared using the greatest size of NaCl particles have the best mechanical properties. Both PMMA- and PCL-based materials can be sterilized by ionizing radiation. In the case of PCL-based scaffolds, irradiation causes cross-linking of polymer chains, which leads to an improvement of the mechanical properties of the scaffold. The compressive elastic modulus for non-porous samples increases with irradiation dose from 1.5 MPa for 0 kGy to 1.9 MPa for 280 kGy. Preliminary in vitro studies indicate good biocompatibility of both materials.

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Additively Manufactured Continuous Cell-Size Gradient Porous Scaffolds: Pore Characteristics, Mechanical Properties and Biological Responses In Vitro

Materials ◽

10.3390/ma13112589 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2589 ◽

Cited By ~ 3

Author(s):

Fei Liu ◽

Qichun Ran ◽

Miao Zhao ◽

Tao Zhang ◽

David Z. Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Pore Size ◽

Cell Size ◽

Porous Scaffolds ◽

Ct Reconstruction ◽

Pore Characteristics ◽

Growth Environment ◽

Size Gradient

Porous scaffolds with graded open porosity combining a morphology similar to that of bone with mechanical and biological properties are becoming an attractive candidate for bone grafts. In this work, scaffolds with a continuous cell-size gradient were studied from the aspects of pore properties, mechanical properties and bio-functional properties. Using a mathematical method named triply periodic minimal surfaces (TPMS), uniform and graded scaffolds with Gyroid and Diamond units were manufactured by selective laser melting (SLM) with Ti-6Al-4V, followed by micro-computer tomography (CT) reconstruction, mechanical testing and in vitro evaluation. It was found that gradient scaffolds were preferably replicated by SLM with continuous graded changes in surface area and pore size, but their pore size should be designed to be ≥ 450 μm to ensure good interconnectivity. Both the Gyroid and Diamond structures have superior strength compared to cancellous bones, and their elastic modulus is comparable to the bones. In comparison, Gyroid exhibits better performances than Diamond in terms of the elastic modulus, ultimate strength and ductility. In vitro cell culture experiments show that the gradients provide an ideal growth environment for osteoblast growth in which cells survive well and distribute uniformly due to biocompatibility of the Ti-6Al-4V material, interconnectivity and suitable pore size.

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In Vitro Degradation of Poly(caprolactone)/nHA Composites

Journal of Nanomaterials ◽

10.1155/2014/802435 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 51

Author(s):

Esperanza Díaz ◽

Iban Sandonis ◽

María Blanca Valle

Keyword(s):

Mechanical Properties ◽

Degradation Products ◽

Degradation Process ◽

Porous Scaffolds ◽

Degradation Behavior ◽

Compressive Properties ◽

Composite Scaffolds ◽

In Vitro Degradation ◽

Poly Caprolactone

The degradation behavior and mechanical properties of polycaprolactone/nanohydroxyapatite composite scaffolds are studied in phosphate buffered solution (PBS), at 37°C, over 16 weeks. Under scanning electron microscopy (SEM), it was observed that the longer the porous scaffolds remained in the PBS, the more significant the thickening of the pore walls of the scaffold morphology was. A decrease in the compressive properties, such as the modulus and the strength of the PCL/nHA composite scaffolds, was observed as the degradation experiment progressed. Samples with high nHA concentrations degraded more significantly in comparison to those with a lower content. Pure PCL retained its mechanical properties comparatively well in the study over the period of degradation. After the twelfth week, the results obtained by GPC analysis indicated a significant reduction in their molecular weight. The addition of nHA particles to the scaffolds accelerated the weight loss of the composites and increased their capacity to absorb water during the initial degradation process. The addition of these particles also affected the degradation behavior of the composite scaffolds, although they were not effective at compensating the decrease in pH prompted by the degradation products of the PCL.

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In Vivo and In Vitro Analyses of Titanium-Hydroxyapatite Functionally Graded Material for Dental Implants

BioMed Research International ◽

10.1155/2021/8859945 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Xinhua Wang ◽

Chengpeng Wan ◽

Xiaoxia Feng ◽

Fuyan Zhao ◽

Huiming Wang

Keyword(s):

Mechanical Properties ◽

Dental Implants ◽

Functionally Graded ◽

Cell Counting ◽

Transcript Levels ◽

Graded Material ◽

Tgf Β1 ◽

Scanning Electron

Purpose. The stress shielding effect caused due to the mechanical mismatch between the solid titanium and the surrounding bone tissue warrants the utilization of a mechanically and biologically compatible material such as the titanium-hydroxyapatite (Ti-HA) functionally graded material (FGM) for dental implants. This study is aimed at fabricating a Ti-HA FGM with superior mechanical and biological properties for dental implantation. Materials and Methods. We fabricated a Ti-HA FGM with different Ti volume fractions (VFs) using HA and Ti powders. Ti-HA was characterized by studying its mechanical properties. Cytotoxicity was examined using a Cell Counting Kit-8 assay and an LDH cell cytotoxicity assay. Scanning electron microscopy was performed on an XL30 environmental scanning electron microscope (ESEM). Alkaline phosphatase (ALP) and transforming growth factor (TGF-β1) expressions were quantitatively monitored using enzyme-linked immunosorbent assay (ELISA) kits. The expressions of TGF-β receptors and ALP genes were measured using real-time polymerase chain reaction. The Ti-HA FGM dental implants were placed in beagle dogs. Microcomputed tomography (CT) and hard tissue slices were performed to evaluate the bone-implant contact (BIC) and bone volume over total volume (BV/TV). Results. The density and mechanical properties of the Ti-HA exhibited various graded distributions corresponding to VF. Based on the results of the Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays, the difference in cytotoxicity between the two groups was statistically nonsignificant ( P = 0.11 ). The ALP and TGF-β1 levels were slightly upregulated. The transcript levels of ALP and TGF-βRI were higher in the Ti-HA groups than in the Ti group at 7 days, whereas the transcript levels of TGF-βRII exhibited no obvious increase. The BIC did not exhibit significant differences between the Ti and Ti-HA FGM groups ( P = 0.0504 ). BV/TV showed the Ti-HA FGM group had better osteogenesis ( P = 0.04 ). Conclusion. Ti-HA FGM contributes to the osteogenesis of dental implants in vivo and in vitro.

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Investigation of Mechanical and Biological Properties of FDM 3D-Printed PLA Scaffolds With Radial Gradient Porosity for Tissue Engineering

10.21203/rs.3.rs-944744/v1 ◽

2021 ◽

Author(s):

Meltem Eryildiz

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Fused Deposition Modeling ◽

Bone Ingrowth ◽

Biological Properties ◽

Porous Scaffolds ◽

Radial Gradient ◽

Fused Deposition ◽

Novel Approach

Abstract Scaffolds with gradient porosity have become very promising candidates for tissue engineering and bone implants because of the combination of better mechanical and biological requirements. In this paper, a novel approach is proposed to design bone scaffolds with gradient porosity similar to the structure of cortical and spongy (cancellous) bones. The radial gradient PLA scaffolds were designed to consist of three different regions with the gyroid infill and, fabricated by Fused deposition modeling (FDM). The biological and mechanical properties of the scaffolds were investigated in vitro. Dense scaffold (G100) had improved mechanical properties but showed decreased bone ingrowth properties. In addition, porous scaffolds provided enhanced biological properties but decreased in mechanical strength (G40-G20). The scaffolds with radial gradient porosity (G100-40-20) gave highest cell proliferation. Because, mean pore size is an important aspect of scaffolds for mimicking bone.

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Characterization and in vitro assessment of three-dimensional extrusion Mg-Sr codoped SiO2-complexed porous microhydroxyapatite whisker scaffolds for biomedical engineering

BioMedical Engineering OnLine ◽

10.1186/s12938-021-00953-w ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Chengyong Li ◽

Tingting Yan ◽

Zhenkai Lou ◽

Zhimin Jiang ◽

Zhi Shi ◽

...

Keyword(s):

Mechanical Properties ◽

Cell Proliferation ◽

Pore Size ◽

Osteogenic Differentiation ◽

Bone Repair ◽

Porous Scaffold ◽

Porous Scaffolds ◽

Sprague Dawley ◽

Active Elements

Abstract Background Large bone defects have always been a great challenge for orthopedic surgeons. The use of a good bone substitute obtained by bone tissue engineering (BTE) may be an effective treatment method. Artificial hydroxyapatite, a commonly used bone defect filler, is the main inorganic component of bones. Because of its high brittleness, fragility, and lack of osteogenic active elements, its application is limited. Therefore, its fragility should be reduced, its osteogenic activity should be improved, and a more suitable scaffold should be constructed. Methods In this study, a microhydroxyapatite whisker (mHAw) was developed, which was doped with the essential trace active elements Mg2+ and Sr2+ through a low-temperature sintering technique. After being formulated into a slurry, a bionic porous scaffold was manufactured by extrusion molding and freeze drying, and then SiO2 was used to improve the mechanical properties of the scaffold. The hydrophilicity, pore size, surface morphology, surface roughness, mechanical properties, and release rate of the osteogenic elements of the prepared scaffold were detected and analyzed. In in vitro experiments, Sprague–Dawley (SD) rat bone marrow mesenchymal stem cells (rBMSCs) were cultured on the scaffold to evaluate cytotoxicity, cell proliferation, spreading, and osteogenic differentiation. Results Four types of scaffolds were obtained: mHAw-SiO2 (SHA), Mg-doped mHAw-SiO2 (SMHA), Sr-doped mHAw-SiO2 (SSHA), and Mg-Sr codoped mHAw-SiO2 (SMSHA). SHA was the most hydrophilic (WCA 5°), while SMHA was the least (WCA 8°); SMHA had the smallest pore size (247.40 ± 23.66 μm), while SSHA had the largest (286.20 ± 19.04 μm); SHA had the smallest Young's modulus (122.43 ± 28.79 MPa), while SSHA had the largest (188.44 ± 47.89 MPa); and SHA had the smallest compressive strength (1.72 ± 0.29 MPa), while SMHA had the largest (2.47 ± 0.25 MPa). The osteogenic active elements Si, Mg, and Sr were evenly distributed and could be sustainably released from the scaffolds. None of the scaffolds had cytotoxicity. SMSHA had the highest supporting cell proliferation and spreading rate, and its ability to promote osteogenic differentiation of rBMSCs was also the strongest. Conclusions These composite porous scaffolds not only have acceptable physical and chemical properties suitable for BTE but also have higher osteogenic bioactivity and can possibly serve as potential bone repair materials.

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Additive Manufacturing and Mechanical Properties of Functionally Graded Medical Ti–35Nb–7Zr–5Ta Porous Scaffolds

Journal of Physics Conference Series ◽

10.1088/1742-6596/1986/1/012036 ◽

2021 ◽

Vol 1986 (1) ◽

pp. 012036

Author(s):

Huihui Cheng

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Functionally Graded ◽

Porous Scaffolds

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Poly(lactide- co -glycolide) porous scaffolds for tissue engineering and regenerative medicine

Interface Focus ◽

10.1098/rsfs.2011.0123 ◽

2012 ◽

Vol 2 (3) ◽

pp. 366-377 ◽

Cited By ~ 235

Author(s):

Zhen Pan ◽

Jiandong Ding

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Regenerative Medicine ◽

Porous Scaffolds ◽

Plga Scaffold ◽

Degradation Rates ◽

Long Time ◽

Facile Fabrication

Porous scaffolds fabricated from biocompatible and biodegradable polymers play vital roles in tissue engineering and regenerative medicine. Among various scaffold matrix materials, poly(lactide- co -glycolide) (PLGA) is a very popular and an important biodegradable polyester owing to its tunable degradation rates, good mechanical properties and processibility, etc. This review highlights the progress on PLGA scaffolds. In the latest decade, some facile fabrication approaches at room temperature were put forward; more appropriate pore structures were designed and achieved; the mechanical properties were investigated both for dry and wet scaffolds; a long time biodegradation of the PLGA scaffold was observed and a three-stage model was established; even the effects of pore size and porosity on in vitro biodegradation were revealed; the PLGA scaffolds have also been implanted into animals, and some tissues have been regenerated in vivo after loading cells including stem cells.

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