Porous calcium aluminate ceramics for bone-graft applications

2002 ◽  
Vol 17 (12) ◽  
pp. 3042-3049 ◽  
Author(s):  
S. J. Kalita ◽  
S. Bose ◽  
A. Bandyopadhyay ◽  
H. L. Hosick
Keyword(s):  
Bone Graft ◽  
Calcium Aluminate ◽  
Volume Fraction ◽  
Cell Attachment ◽  
Average Pore Size ◽  
Average Pore ◽  
Fused Deposition ◽  
Osteoblast Cell Line ◽  
Controlled Porosity

Calcium aluminate scaffolds with controlled porosity were processed for bone-graft applications. Indirect fused deposition process was used to fabricate these structures. Phase analyses were done using x-ray diffraction technique on powdered samples of calcium aluminates at different compositions. Hg porosimetry was used to determine the pore sizes and the pore volumes present in these controlled porosity structures at different calcium aluminate compositions. Cylindrical samples were tested under uniaxial compressive loading as a function of composition and volume fraction porosity (VFP). Samples of 29% and 44% VFP (designed) with average pore size of 300 μm showed compressive strength between 2 and 24 MPa. Cytotoxicity and cell proliferation studies were conducted with a modified human osteoblast cell line (HOB). These materials showed good cell attachment and a steady cell growth behavior with HOB cells during the first three weeks of in vitro analyses.

Fabrication and Characterization of Mechanically Reinforced Collagen Sponge

2005 ◽  
Vol 288-289 ◽  
pp. 385-388
Author(s):  
Yosuke Hiraoka ◽  
Ueda Hiroki ◽  
Yu Kimura ◽  
Yasuhiko Tabata
Keyword(s):  
Cell Attachment ◽  
Average Pore Size ◽  
Collagen Sponge ◽  
Average Pore ◽  
Culture Studies ◽  
Collagen Solution ◽  
Freeze Dried ◽  
Interconnected Pore

This study describes an investigation of collagen sponge mechanically reinforced through the incorporation of poly(glycolic acid)(PGA) fiber. A collagen solution with PGA fiber homogeneously dispersed was freeze-dried, followed by dehydrothermal cross-linking to obtain collagen sponges incorporating PGA fiber. A collagen sponge without PGA fiber was prepared similarly by using the collagen solution. By scanning electron observation, the collagen sponges exhibited isotropic and interconnected pore structures with an average pore size of 180 µm, irrespective of PGA fiber incorporation. As expected, PGA fiber incorporation enabled the collagen sponge to significantly enhance the compression strength. In vitro cell culture studies revealed that the number of L929 fibroblasts initially attached was significantly greater for the collagen sponge incorporating PGA fiber than for the collagen sponge. In vitro cell proliferation studies revealed that the proliferation of cell was higher for the collagen sponge incorporating PGA fiber, by day 21, than the collagen sponge without PGA fiber. It is possible that shrinkage suppression results in the superior cell attachment and proliferation of sponge incorporating PGA fiber. After subcutaneous implantation into the backs of mice, the residual volume of collagen sponge incorporating PGA fiber was significantly large compared with that of collagen sponge. We concluded that the incorporation of PGA fiber is a simple way to reinforce collagen sponge without impairing the biocompatibility.

scholarly journals The Effect of Pore Directionality of Collagen Scaffolds on Cell Differentiation and In Vivo Osteogenesis

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3187
Author(s):  
Miguelangel Moncayo-Donoso ◽  
Gustavo A. Rico-Llanos ◽  
Diego A. Garzón-Alvarado ◽  
José Becerra ◽  
Rick Visser ◽  
...  
Keyword(s):  
Bone Growth ◽  
Cell Attachment ◽  
Average Pore Size ◽  
Bone Matrix ◽  
Osteoblastic Differentiation ◽  
Collagen Scaffolds ◽  
Average Pore ◽  
Native Bone

Although many bone substitutes have been designed and produced, the development of bone tissue engineering products that mimic the microstructural characteristics of native bone remains challenging. It has been shown that pore orientation within collagen scaffolds influences bone matrix formation by the endochondral route. In addition, that the unidirectional orientation of the scaffolds can limit the growth of blood vessels. However, a comparison between the amount of bone that can be formed in scaffolds with different pore orientations in addition to analyzing the effect of loading osteogenic and proangiogenic factors is still required. In this work we fabricated uni- and multidirectional collagen sponges and evaluated their microstructural, physicochemical, mechanical and biological characteristics. Although the porosity and average pore size of the uni- and multidirectional scaffolds was similar (94.5% vs. 97.1% and 260 µm vs. 269 µm, respectively) the unidirectional sponges had a higher tensile strength, Young’s modulus and capacity to uptake liquids than the multidirectional ones (0.271 MPa vs. 0.478 MPa, 9.623 MPa vs. 3.426 MPa and 8000% mass gain vs. 4000%, respectively). Culturing of rat bone marrow mesenchymal stem cells demonstrated that these scaffolds support cell growth and osteoblastic differentiation in the presence of BMP-2 in vitro, although the pore orientation somehow affected cell attachment and differentiation. The evaluation of the ability of the scaffolds to support bone growth when loaded with BMP-2 or BMP-2 + VEGF in an ectopic rat model showed that they both supported bone formation. Histological analysis and quantification of mineralized matrix revealed that the pore orientation of the collagen scaffolds influenced the osteogenic process.

Development of Porous Polymer-Ceramic Composites as Bone Grafts

2002 ◽  
Vol 726 ◽  
Author(s):  
Samar Kalita ◽  
John Finley ◽  
Susmita Bose ◽  
Howard Hosick ◽  
Amit Bandyopadhyay
Keyword(s):  
Pore Size ◽  
Fused Deposition Modeling ◽  
Average Pore Size ◽  
Polymeric Materials ◽  
Ceramic Composites ◽  
Porous Polymer ◽  
Fused Deposition ◽  
Dog Bone ◽  
Osteoblast Cell Line ◽  
Controlled Porosity

AbstractBiomaterials have made significant contributions to the advancement of modern health care and drug delivery industries. The present research is based on development of porous polymerceramic composite scaffolds using polypropylene (PP) polymer and tricalcium phosphate (TCP) ceramic for bone-graft applications. Three dimensionally interconnected controlled porosity scaffolds were fabricated using a fused deposition modeling (FDM) system. First, ceramic and polymeric materials were compounded under high shear using a torque rheometer. Compounded materials were then extruded to a 1.78mm diameter continuous filament using a single screw extruder. These filaments were used as a feedstock material for an FDM 1650 machine for direct fabrication of controlled porosity parts. Hg-porosimetry was done to determine pore size and their distribution in these structures. Tensile properties of neat composites and as received polymer were measured and compared using standard dog bone samples. Uniaxial compression tests were performed on cylindrical porous samples having average pore size of 160 μm and 36 vol% porosity. These samples showed an average ultimate compressive strength of 12.7 MPa. Average compressive modulus was calculated as 263 MPa. Cytotoxicity and cell proliferation studies were conducted with OPC1 modified human osteoblast cell-line. It was found that composite matrices were non-toxic and they showed excellent cell growth with OPC1 cells.

Evaluation of 5% Na2O-Incorporated Calcium Metaphosphate as a Scaffold for Tissue-Engineered Bone Regeneration

2006 ◽  
Vol 309-311 ◽  
pp. 985-988 ◽  
Author(s):  
J.H. Yoon ◽  
J.T. Kim ◽  
Eui Kyun Park ◽  
Shin Yoon Kim ◽  
Chang Kuk You ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Bone Regeneration ◽  
Average Pore Size ◽  
Ectopic Bone Formation ◽  
Cellular Reaction ◽  
Average Pore ◽  
Cellular Attachment ◽  
Ectopic Bone ◽  
Osteogenic Effect

As a part of the effort to develop a suitable scaffold for tissue-engineered bone regeneration, we modified calcium metaphosphate (CMP) ceramic with Na20 and evaluated its efficiency as a scaffold. We incorporate 5% Na20 into pure CMP and prepare for an average pore size of 250 or 450 µm average pore sizes. The incorporation of 5% Na2O caused reduced compressive strength and there was no change in biodegradability. The in vitro cellular attachment and proliferation rate, however, were slightly improved. The 5% Na2O-incorporated macroporous CMP ceramic-cell constructs treated with Emdogain induced ectopic bone formation more effectively than those without Emdogain treatment. These results suggest that the incorporation of 5% Na2O into pure CMP is not effective for improving the physical characteristics of pure CMP but it is positive for improving the cellular reaction and osteogenic effect with the addition of Emdogain.

Determination of Local Mechanical Properties of Si3N4 Based Foams

2014 ◽  
Vol 606 ◽  
pp. 213-216 ◽  
Author(s):  
Zuzana Vilčeková ◽  
Monika Kašiarová ◽  
Magdaléna Domanická ◽  
Miroslav Hnatko ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Resonant Frequency ◽  
Volume Fraction ◽  
Average Pore Size ◽  
Polyurethane Foams ◽  
Average Pore ◽  
Replication Method ◽  
Highly Porous

Local mechanical properties, particularly the hardness and Youngs modulus of highly porous silicon nitride based foams were studied in this work. Silicon nitride foams were prepared using polyurethane foam replication method to obtain appropriate cellular structure suitable for bio-application. Two types of the polyurethane foams were used (with average pore size 0.48 mm and 0.62 mm). Some of these samples were prepared by single or multiple infiltrations. The effects of structures, temperature of calcination, volume fraction of Si3N4 powder and number of the infiltrations on the local mechanical properties were investigated. The Youngs modulus of studied samples range from 12 to 46 GPa at the macroscopic scale measured by resonant frequency technique and from 10 to 28 GPa at the microscopic scale measured by instrumented indentation. Results showed increase of the hardness and Youngs modulus with increasing of the calcination temperature, with increasing of the number of infiltrations and also with increasing of volume fraction of Si3N4 powder in suspension. The results obtained from nanoindentation carry out lower values in comparison with the values measured by resonant frequency technique.

scholarly journals Preparation and Evaluation of Bioactivity of Porous Bioglass Tablets for Bone Tissue Regeneration

2019 ◽  
Vol 1 (3) ◽  
pp. 112-123
Author(s):  
Rohith Kumar R. ◽  
Sangeetha Ashok Kumar ◽  
K. Periyasami Bhuvana
Keyword(s):  
Surface Characterization ◽  
Mechanical Stability ◽  
Average Pore Size ◽  
High Surface ◽  
Bone Tissue Regeneration ◽  
Average Pore ◽  
Hydroxy Apatite ◽  
Sbf Solution

The present study endeavors in the preparation and characterization of semi crystalline 45S5 bioglass (BG) (SiO2-CaO-P2O5) through sol gel process. Dry press mold technique was used in the preparation porous BG tablets to examine the bioactivity through invitro studies. The synthesized BG powder was subjected to structural, morphological and mechanical characterization and the bioactivity was examined in vitro by immersing the BG tablet in the Simulated Body Fluid (SBF) solution. XRD pattern and the SEM micrographs revealed the semi crystalline nature of BG with spherical morphology. The elemental analysis confirms the presence of vital constituents required for Bone regeneration (Calcium, Phosphorous, Silica, and Sodium). The surface characterization of BG tablet reveals the pores structure of average pore size of 240nm which contributed to the high surface activity resulting in formation of carbonated hydroxy apatite (HCAP) when immersed in SBF. The disintegration studies denoted the stabilization period was after 48 of immersion of BG tablets in SBF solution. The compressive strength measurement of the tablet also reveals the higher mechanical stability.

Controlled Porosity Ceramics for Bone Graft Applications

2000 ◽  
Author(s):  
S. Bose ◽  
J. Darsell ◽  
R. Kintner ◽  
K. Feely ◽  
H. L. Hosick ◽  
...  
Keyword(s):  
Pore Size ◽  
Fused Deposition Modeling ◽  
Mechanical Tests ◽  
In Vitro Tests ◽  
Slice Thickness ◽  
Connective Tissues ◽  
Fused Deposition ◽  
Significant Research ◽  
Controlled Porosity

Abstract Significant research has already been done for the development of bioceramic materials with controlled microstructures using inert, bioactive and bioresorbable ceramics. Microporous implants with controlled pore size in the range of 100-600 μm have proven to be osteoconductive. A minimum pore size of 100 μm is necessary for tissue in-growth and to provide blood supply to the connective tissues to keep them viable and healthy. Bone in-growth takes place within the inter-connected pore channels near the surface and maintains its vascularity and long term viability, and the implant serves as a structural bridge or scaffold for bone formation. Controlled porosity ceramic scaffolds were fabricated using indirect fused deposition modeling (FDM), a commercially available rapid prototyping process, with alumina and tricalcium phosphate (TCP) ceramics. Pore size and pore volumes were varied by changing road width, road gap and slice thickness of the polymeric molds. Mechanical tests were conducted to understand the influence of porosity parameters on strength degradation. In vitro tests were carried out with human osteoblast (HOB) cells to understand the effects of porosity parameters on cell growth. The paper describes the effects of porosity on the biocompatibility and bio-mechanical properties of controlled porosity alumina and TCP scaffolds.

scholarly journals In Vitro Performance and Chemical Stability of Lipid-Based Formulations Encapsulated in a Mesoporous Magnesium Carbonate Carrier

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 426
Author(s):  
Caroline Alvebratt ◽  
Tahnee J. Dening ◽  
Michelle Åhlén ◽  
Ocean Cheung ◽  
Maria Strømme ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Oral Absorption ◽  
Physical Adsorption ◽  
Average Pore Size ◽  
In Vitro Digestion ◽  
Magnesium Carbonate ◽  
Resonance Spectroscopy ◽  
Average Pore ◽  
In Vitro Performance

Lipid-based formulations can circumvent the low aqueous solubility of problematic drug compounds and increase their oral absorption. As these formulations are often physically unstable and costly to manufacture, solidification has been suggested as a way to minimize these issues. This study evaluated the physicochemical stability and in vitro performance of lipid-loaded mesoporous magnesium carbonate (MMC) particles with an average pore size of 20 nm. A medium chain lipid was loaded onto the MMC carrier via physical adsorption. A modified in vitro lipolysis setup was then used to study lipid release and digestion with 1H nuclear magnetic resonance spectroscopy. The lipid loading efficiency with different solidification techniques was also evaluated. The MMC, unlike more commonly used porous silicate carriers, dissolved during the lipolysis assay, providing a rapid release of encapsulated lipids into solution. The digestion of the dispersed lipid-loaded MMC therefore resembled that of a coarse dispersion of the lipid. The stability data demonstrated minor degradation of the lipid within the pores of the MMC particles, but storage for three months did not reveal extensive degradation. To conclude, lipids can be adsorbed onto MMC, creating a solid powder from which the lipid is readily released into the solution during in vitro digestion. The chemical stability of the formulation does however merit further attention.

scholarly journals Synthesis of Thermal Polymerizable Alginate-GMA Hydrogel for Cell Encapsulation

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaokun Wang ◽  
Tong Hao ◽  
Jing Qu ◽  
Changyong Wang ◽  
Haifeng Chen
Keyword(s):  
Umbilical Vein ◽  
Average Pore Size ◽  
Three Dimensional ◽  
Cell Encapsulation ◽  
Myocardial Repair ◽  
Average Pore ◽  
Umbilical Vein Endothelial Cells

Alginate is a negative ionic polysaccharide that is found abundantly in nature. Calcium is usually used as a cross-linker for alginate. However, calcium cross-linked alginate is used only forin vitroculture. In the present work, alginate was modified with glycidyl methacrylate (GMA) to produce a thermal polymerizable alginate-GMA (AA-GMA) macromonomer. The molecular structure and methacrylation (%DM) of the macromonomer were determined by1H NMR. After mixing with the correct amount of initiator, the AA-GMA aqueous solution can be polymerized at physiological temperature. The AA-GMA hydrogels exhibited a three-dimensional porous structure with an average pore size ranging from 50 to 200 μm, directly depending on the macromonomer concentration. Biocompatibility of the AA-GMA hydrogel was determined byin vivomuscle injection and cell encapsulation. Muscle injectionin vivoshowed that the AA-GMA solution mixed with initiator could form a hydrogelin situand had a mild inflammatory effect. Human umbilical vein endothelial cells (HUVECs) were encapsulated in the AA-GMA hydrogelsin situat 37°C. Cell viability and proliferation were unaffected by macromonomer concentrations, which suggests that AA-GMA has a potential application in the field of tissue engineering, especially for myocardial repair.

Formation of Calcium Phosphate-Ellagic Acid Composites by Layer by Layer Assembly for Cellular Attachment to Osteoblasts

2012 ◽  
Vol 13 ◽  
pp. 1-17
Author(s):  
Ipsita A. Banerjee ◽  
Karl R. Fath ◽  
Nako Nakatsuka ◽  
Nazmul H. Sarker ◽  
Ipsita A. Banerjee
Keyword(s):  
Calcium Phosphate ◽  
Ellagic Acid ◽  
Liquid Crystalline ◽  
Average Pore Size ◽  
Layer By Layer ◽  
Average Pore ◽  
Assembly Method ◽  
Cellular Attachment ◽  
New Strategy

The quest for new biomaterials to serve as cell scaffolds for applications in tissue engineering is of prime importance. In this work, we investigated microfiber assemblies of Ellagic Acid (EA), a plant polyphenol to serve as scaffolds for attachment and proliferation of osteoblasts. The advantage of Ellagic Acid self-assembling system is its intrinsic ability to order into multiple layers due to its capability to form liquid crystalline assemblies. We prepared ellagic acid-microfiber composites by the layer-by-layer (LBL) assembly method, where collagen (COL), poly-Arginine (poly-R), and calcium phosphate nanocrystals were coated on the surface of ellagic acid microfibers. The attachment of the various layers was confirmed by various spectroscopic and microscopic methods. The samples were found to be porous with an average pore size of 600 nm. The formed microconjugates were biodegradable and supported the growth of human fetal osteoblast (hFOB) cells in vitro. Our findings suggest that this system not only promotes initial cell adhesion but also can be utilized to deliver the vital biological molecule ellagic acid to cells at the scaffold interface and displays a new strategy for the design of biomaterials.

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