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

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2589 ◽  
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.

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

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.

Influence of the Unit Cell Geometrical Parameter to the Mechanical Properties of Ti6Al4V Open-Porous Scaffolds Manufactured by Selective Laser Melting

2016 ◽  
Vol 851 ◽  
pp. 201-210 ◽  
Author(s):  
Ying Wang ◽  
Ji Min Chen ◽  
Yan Ping Yuan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Pore Size ◽  
Selective Laser Melting ◽  
Geometrical Parameter ◽  
Unit Cell ◽  
Geometrical Parameters ◽  
Porous Scaffolds ◽  
Laser Melting ◽  
Element Analysis

Selective laser melting (SLM) are getting more and more established as reliable methods for producing open-porous scaffolds with accurately controlled pore size, strut size, and porosity. However, the optimal geometrical parameter of the unit cell by SLM remained unclear. In this study, we evaluated the effect of unit geometrical parameters to the mechanical properties of porous scaffolds by finite element analysis method and Mechanical testing method. Six rhombic dodecahedron unit cells were designed with different geometrical parameter and the scaffolds manufactured by SLM using Ti6Al4V. The compression testing results show that the specimens with the same pore size, the elastic modulus and the strength are increased with increasing strut size and the specimens with the same strut size, the elastic modulus and the strength are decreased with increasing strut size. The porosity can be calculated by pore size and strut size. The compression strength of the porous scaffolds is 114MPa~258MPa and the quasi-elastic gradient is 3.18Gpa~8.64Gpa, which are similar to human bone. The simulation values are different from the experiment values but the variation tendency is in accordance.

scholarly journals Development of Biopolymeric Hybrid Scaffold-Based on AAc/GO/nHAp/TiO2 Nanocomposite for Bone Tissue Engineering: In-Vitro Analysis

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1319
Author(s):  
Muhammad Umar Aslam Khan ◽  
Wafa Shamsan Al-Arjan ◽  
Mona Saad Binkadem ◽  
Hassan Mehboob ◽  
Adnan Haider ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Guar Gum ◽  
Porous Scaffolds ◽  
Vitro Assay ◽  
Vitro Analysis ◽  
Nanocomposite 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.

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

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1711 ◽  
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.

IN VITRO EXPERIMENTS ON LASER SINTERED POROUS PCL SCAFFOLDS WITH POLYMER HYDROGEL FOR BONE REPAIR

2011 ◽  
Vol 11 (05) ◽  
pp. 983-992 ◽  
Author(s):  
MING-YIH LEE ◽  
SI-WEN LIU ◽  
JYH-PING CHEN ◽  
HAN-TSUNG LIAO ◽  
WEN-WEI TSAI ◽  
...  
Keyword(s):  
Pore Size ◽  
Bone Repair ◽  
In Vitro Study ◽  
Experimental Results ◽  
Porous Scaffolds ◽  
Immersion Method ◽  
Titration Method ◽  
Polymer Hydrogel ◽  
Loading Methods

Bone defects caused by tumors, diseased infection, trauma or abnormal bone development create a lot of serious health problems. Tissue engineering aims to fabricate tissues or organs using patients' cells for repairing the damaged tissues or organs in clinic. The aim of this study was to design and fabricate polycaprolactone (PCL) scaffolds using the inhouse-built selective laser sintering (SLS) rapid prototyping (RP) machine and combining with polymer hydrogel for in vitro study for bone repair. In this study, three configurations of scaffolds structure (0/45/0/45°, 0/90/0/90°, and 0/45/90/135° patterns) were designed and produced. The compressive modulus, porosity and pore size of porous scaffolds were first determined. In addition, polymer hydrogel was combined with PCL scaffolds with three loading methods (i.e., immersion method, injection method and titration method) to enhance scaffolds surface hydrophilicity for cell proliferation. Mesenchymal stem cells from New Zealand White rabbits were loaded on PCL scaffolds and induced to osteoblasts in vitro. Bone formation was determined by MTS assays, von Kossa stains and ALP activities. The experimental results showed the compressive moduli of scaffolds with 0/45/0/45°, 0/90/0/90°, and 0/45/90/135° patterns was 2 MPa, 3.4 MPa, and 3.75 MPa, respectively. The porosity of scaffolds was 72%, 76%, and 83%, respectively. The ranges of pore size of scaffolds were 350–400 μm, 400–500 μm, and 350–400 μm, respectively. By comparing three kinds of polymer hydrogel loading methods, titration method had the best result. The in vitro experimental results revealed that OD values of MTS tests and ALP activities increased from day 7 to day 21 and von Kossa stain revealed dark brown mineralized tissue, indicating cells could proliferate and differentiate in polymer hydrogel and scaffolds.

Mechanically Enhanced Precipitation of Phase-Inversion Sprayed Polyurethane Scaffold May Be Used to Match Tissue Specific Anisotropy

2009 ◽  
Author(s):  
James P. Kennedy ◽  
Robert W. Hitchcock
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Culture ◽  
Pore Size ◽  
Phase Inversion ◽  
Anisotropy Ratio ◽  
Material Anisotropy ◽  
Polyurethane Scaffold ◽  
Stiffness Anisotropy

Methods of creating a scaffold for tissue engineering that allow for modification of properties such as pore size, porosity, and anisotropy are essential for tissue engineering applications. For example the pore size and material anisotropy have been shown to affect cardiomyocyte elongation and alignment [1]. Phase-inversion spray polymerization (PISP) is a method for rapidly precipitating polymers onto a surface by depositing the polymer solution simultaneously with a nonsolvent, and may be used to create biocompatible scaffolds of engineered morphological and mechanical properties by varying the solubility of the polymer in the nonsolvent [2]. We report here on the fabrication of scaffolds using different nonsolvents and methods of in-process elongation that allow for control of stiffness, anisotropy ratio, porosity, and in vitro cell culture.

In vitro and in vivo characteristics of PCL scaffolds with pore size gradient fabricated by a centrifugation method

Biomaterials ◽  
2007 ◽  
Vol 28 (9) ◽  
pp. 1664-1671 ◽  
Author(s):  
Se Heang Oh ◽  
Il Kyu Park ◽  
Jin Man Kim ◽  
Jin Ho Lee
Keyword(s):  
Pore Size ◽  
Centrifugation Method ◽  
Size Gradient

scholarly journals Electrospun polyester-urethane scaffold preserves mechanical properties and exhibits strain stiffening during in situ tissue ingrowth and degradation

2019 ◽  
Author(s):  
Hugo Krynauw ◽  
Rodaina Omar ◽  
Josepha Koehne ◽  
Georges Limbert ◽  
Neil H Davies ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Performance ◽  
Hydrolytic Degradation ◽  
Material Strength ◽  
Fibre Direction ◽  
Tissue Ingrowth ◽  
Polyester Urethane

AbstractConsistent mechanical performance from implantation through healing and scaffold degradation is highly desired for tissue-regenerative scaffolds, e.g. when used for vascular grafts. The aim of this study was the paired in vivo mechanical assessment of biostable and fast degrading electrospun polyester-urethane scaffolds to isolate the effects of material degradation and tissue formation after implantation. Biostable and degradable polyester-urethane scaffolds with substantial fibre alignment were manufactured by electrospinning. Scaffold samples were implanted paired in subcutaneous position in rats for 7, 14 and 28 days. Morphology, mechanical properties and tissue ingrowth of the scaffolds were assessed before implantation and after retrieval. Tissue ingrowth after 28 days was 83 ± 10% in the biostable scaffold and 77 ± 4% in the degradable scaffold. For the biostable scaffold, the elastic modulus at 12% strain increased significantly between 7 and 14 days and decreased significantly thereafter in fibre but not in cross-fibre direction. The degradable scaffold exhibited a significant increase in the elastic modulus at 12% strain from 7 to 14 days after which it did not decrease but remained at the same magnitude, both in fibre and in cross-fibre direction. Considering that the degradable scaffold loses its material strength predominantly during the first 14 days of hydrolytic degradation (as observed in our previous in vitro study), the consistency of the elastic modulus of the degradable scaffold after 14 days is an indication that the regenerated tissue construct retains it mechanical properties.

scholarly journals Bioactivity and Bone Cell Formation with Poly-ε-Caprolactone/Bioceramic 3D Porous Scaffolds

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2718
Author(s):  
Po-Kai Juan ◽  
Fang-Yu Fan ◽  
Wei-Chun Lin ◽  
Pei-Bang Liao ◽  
Chiung-Fang Huang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Cell Attachment ◽  
Ph Value ◽  
Ceramic Powder ◽  
High Ratio ◽  
Porous Scaffolds ◽  
Alp Activity ◽  
Mg63 Cells ◽  
Human Cancellous Bone

This study applied poly-ε-caprolactone (PCL), a biomedical ceramic powder as an additive (nano-hydroxyapatite (nHA) or β-tricalcium diphosphate (β-TCP)), and sodium chloride (NaCl) and ammonium bicarbonate ((NH4)HCO3) as porogens; these stuffs were used as scaffold materials. An improved solvent-casting/particulate-leaching method was utilized to fabricate 3D porous scaffolds. In this study we examined the physical properties (elastic modulus, porosity, and contact angle) and degradation properties (weight loss and pH value) of the 3D porous scaffolds. Both nHA and β-TCP improved the mechanical properties (elastic modulus) of the 3D porous scaffolds. The elastic modulus (0.15~1.865 GPa) of the various composite scaffolds matched that of human cancellous bone (0.1~4.5 GPa). Osteoblast-like (MG63) cells were cultured, a microculture tetrazolium test (MTT) was conducted and alkaline phosphatase (ALP) activity of the 3D porous scaffolds was determined. Experimental results indicated that both nHA and β-TCP powder improved the hydrophilic properties of the scaffolds. The degradation rate of the scaffolds was accelerated by adding nHA or β-TCP. The MTT and ALP activity tests indicated that the scaffolds with a high ratio of nHA or β-TCP had excellent properties of in vitro biocompatibility (cell attachment and proliferation).

scholarly journals In vitro and in vivo evaluations of the fully porous Ti6Al4V acetabular cups fabricated by a sintering technique

RSC Advances ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 6724-6732 ◽  
Author(s):  
Ji Li ◽  
Wei Li ◽  
Zhongli Li ◽  
Yuxing Wang ◽  
Ruiling Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Total Hip Arthroplasty ◽  
Pore Size ◽  
Hip Arthroplasty ◽  
High Porosity ◽  
Total Hip ◽  
Large Pore ◽  
Large Pore Size

The fully porous Ti6Al4V cup fabricated by the sintered technique showed high porosity, large pore size with good mechanical properties. It may be effective in achieving in vivo stability after the total hip arthroplasty.

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