scholarly journals Development of bioactive and biocompatible ceramic composites based on potassium polytitanate

2019 ◽  
Vol 13 (2) ◽  
pp. 149-156
Author(s):  
Ángel Villalpando-Reyna ◽  
Dora Cortés-Hernández ◽  
Jose Granjeiro ◽  
Marcelo Prado ◽  
Alexander Gorokhovsky ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Negative Control ◽  
Calcium Titanate ◽  
In Vitro Cytotoxicity ◽  
Apatite Formation ◽  
Potassium Polytitanate

Bioactive and biocompatible composites were successfully prepared by reactive sintering of mixtures of a crystalline titanate precursor and 45S5 Bioglass?. The polytitanate/glass precursor ratios were 20/80, 40/60, 60/40 or 80/20 (wt.%). The powder mixtures were uniaxially pressed and heat treated at 1000 ?C for 1 h. During sintering, intensive interactions between raw materials occurred. The formed main crystalline phases were: potassium hexatitanate (K2Ti6O13), calcium titanate (CaTiO3), calcium silicate (CaSiO4) and sodium-calcium silicate (Na6Ca3Si6O18). Additionally, a Si-rich glassy phase was also observed. The mechanism of apatite formation indicated that both crystalline and amorphous phases play important roles in this process. A homogeneous apatite layer was formed on Si-OH, Ti-OH-rich interfaces. In vitro bioactivity was assessed using simulated body fluid (SBF K-9). The in vitro cytotoxicity behaviour was evaluated using a human osteoblastlike cells model and compressive strength by ASTM C-773 standard. All the composites demonstrated high bioactivity as cytotoxicity assays indicated a biocompatibility similar to that of the negative control. The samples showed high cell adherence and elongation cell characteristics similar to those observed on biocompatible systems. The compressive strength of the sintered samples decreased as the polytitanate content precursor was increased. The results obtained indicate that these materials are highly promising composites for medical applications.

Apatite-Forming Ability of Organic-Inorganic Hybrids Prepared from Calcium Silicate and Glucomannan

2007 ◽  
Vol 361-363 ◽  
pp. 567-570
Author(s):  
Yasuyuki Morita ◽  
Toshiki Miyazaki ◽  
Eiichi Ishida ◽  
Chikara Ohtsuki
Keyword(s):  
Calcium Silicate ◽  
Body Fluid ◽  
Organic Polymer ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Living Body ◽  
Bioactive Ceramics ◽  
Previously Treated

So-called bioactive ceramics are used for bone-repairing owing to attractive features such as direct bone-bonding in living body. However, there is limitation on clinical applications due to their inappropriate mechanical properties performances such as higher brittleness and lower fracture toughness than natural bone. To overcome this problem, hybrid materials have been developed by modification of calcium silicate, that is basic component of bioactive ceramics, with organic polymer. It is known that bioactive ceramics bond to bone through bone-like apatite layer which is formed on their surfaces by chemical reaction with body fluid. We attempted preparation of bioactive organic-inorganic hybrids from Glucomannan that is a kind of complex polysaccharide, and calcium silicate. Hybrids were prepared from glucomannan and tetraethoxysilane (TEOS). They were treated with 1M (=mol·m-3) CaCl2 aqueous solution for 24 hours. Then ability of apatite formation on the hybrids was examined in vitro using simulated body fluid (SBF, Kokubo solution). Surface structure of the specimens was examined by thin-film X-ray diffraction (TF-XRD), scanning electron microscopic (SEM) observation. The hybrids with TEOS:Glucomannan= 1:1 to 4:1 in mass ratio formed the apatite in SBF within 3 or 7 d, when they were previously treated with CaCl2 solution.

Protein Precipitation In Vitro as a Measure of Chemical-induced Cytotoxicity: An EDIT Sub-programme

2001 ◽  
Vol 29 (3) ◽  
pp. 309-324
Author(s):  
Apolonia Novillo ◽  
Barbro Ekwall ◽  
Argelia Castaño
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Exposure Period ◽  
Negative Control ◽  
In Vitro Cytotoxicity ◽  
Protein Precipitation ◽  
In Vitro Toxicity ◽  
Human Cell Lines ◽  
Response Curves

As a priority area of the Evaluation-Guided Development of In Vitro Toxicity and Toxicokinetic Tests (EDIT) programme, an in vitro protein precipitation (PP) assay was used on the 50 reference chemicals of the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) project, to confirm and extend the MEIC results. Dose–response curves were generated for only 30 of the chemicals, and the concentrations causing 10% (EC10) and 50% (EC50) protein precipitation versus the positive control were chosen as endpoints. The number of chemicals with a positive response increased to 46 when a new endpoint, the minimum effect concentration (MEC) that induces protein precipitation with respect to the negative control, was used. When the results were correlated with in vitro cytotoxicity in human cell lines, a similarly good correlation was found between the various endpoints of the PP assay at 5 hours and the 24-hour IC50 average cytotoxicity in human cell lines, even though the number of chemicals included in the correlation was larger for the MEC. Using the prediction error, the endpoint that gave the best correlation between the PP assay and human cell cytotoxicity was once more found to be the 5-hour MEC, and this was chosen for the PP assay. The sensitivity of the PP assay is lower than that of the in vitro cell-line cytotoxicity assay, possibly due to its shorter exposure period and because precipitation is the ultimate event in the sequence of a protein disturbance. It is expected that earlier denaturation steps would give better sensitivity. However, this simple, inexpensive and rapid assay could be useful in the early stages of testing chemicals.

Preparation and Characterization of Calcium Silicate Slag Based Lightweight Wall Materials

2012 ◽  
Vol 512-515 ◽  
pp. 110-114 ◽  
Author(s):  
Lei Hou ◽  
Jin Hong Li ◽  
Ling Xin Tong
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Calcium Silicate ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Potassium Feldspar ◽  
Water Soluble ◽  
Silicate Slag ◽  
Calcium Silicate Slag ◽  
Wall Materials

Potassium feldspar (KAlSi3O8) can be used to extract potassium to solve the shortage of water soluble potash resources in China, but it will produce large amount of calcium silicate slag. Resource recycling from calcium silicate slag can be realized by synthesising wall materials. In this research， calcium silicate slag based lightweight wall materials have been successfully prepared by calcium silicate hydrates (CSH), lime and fly ash through autoklave process. Furthermore, the wall materials are charactered by strength determination, X-ray diffraction (XRD) analysis, and Scanning electron microscopy (SEM) analysis. The results show that the compressive strength is mainly influenced by the lime/fly ash mass ratio (L/F), CSH content and water/solid ratio (W/S). The compressive strength of 21.1-23.9 MPa and density of 0.87-0.91 g/cm3 are achieved respectively with the L/F value of 0.82-1.00, CSH content of 70 % and W/S of 0.9. The main hydrate product of wall materials is 11Å tobermorite [Ca5(OH)2Si6O16•4H2O], which is partly formed from the phase transformation of CSH, and partly produced by the reaction among raw materials during the process of autoclaving. The tobermorite is easy formed at low L/F value and it has a contribution to the low density for its flake-like structure that make the materials porous.

scholarly journals Improved bioactivity of GUMMETAL®, Ti59Nb36Ta2Zr3O0.3, via formation of nanostructured surfaces

2018 ◽  
Vol 9 ◽  
pp. 204173141877417 ◽  
Author(s):  
Shiva Kamini Divakarla ◽  
Seiji Yamaguchi ◽  
Tadashi Kokubo ◽  
Dong-Wook Han ◽  
Jae Ho Lee ◽  
...  
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Cell Attachment ◽  
Cell Number ◽  
Calcium Titanate ◽  
Apatite Formation ◽  
X Ray ◽  
Nanostructured Surfaces ◽  
Implant Integration

The leading reason for implant revision surgery globally is lack of implant integration with surrounding bone. A new titanium alloy GUMMETAL® (Ti59Nb36Ta2Zr3O0.3) is currently used in biomedical devices and has a Young’s modulus that is better matched to bone. The surface was subject to NaOH, CaCl2, heat and water treatment (BioGum) after which the surfaces were evaluated using atomic force microscope, scanning electron microscope, X-ray diffractometer and elemental analysis using energy dispersive X-ray. To demonstrate enhanced bone bonding ability and cytocompatibility, apatite formation in simulated body fluid and in vitro stem cell attachment, proliferation and cytoskeleton organisation were examined. The formation of a ~200 nm nanoscale needle-like calcium titanate network on the surface following treatment was revealed and upon soaking in simulated body fluid, the formation of a ~5 µm layer of apatite. Metabolic activity of rat bone marrow stem cells on BioGum was increased in comparison to control and the cell number appeared greater, with more elongated morphology as early as 2 h post-seeding. This positions the modification as a simple and potentially universal technology for the improvement of implant integration.

Preparation of Porous Hydroxyapatite as Synthetic Scaffold Using Powder Deposition and Sintering and Cytotoxicity Evaluation

2013 ◽  
Vol 747 ◽  
pp. 123-126 ◽  
Author(s):  
Eko Pujiyanto ◽  
Alva Edy Tontowi ◽  
Muhammad Waziz Wildan ◽  
Widowati Siswomihardjo
Keyword(s):  
Compressive Strength ◽  
Mercury Porosimetry ◽  
Chemical Properties ◽  
Vero Cells ◽  
In Vitro Cytotoxicity ◽  
Mixed Powder ◽  
Porous Hydroxyapatite ◽  
Powder Deposition ◽  
Synthetic Scaffold

This study prepared porous hydroxyapatite (porous HA) as synthetic scaffold and find out chemical properties, porosity, compressive strength and cytotoxicity properties. Porous HA was prepared by powder deposition and sintering from HA-PMMA mixed powder. Porous HA characterizations were conducted by XRD, XRF, SEM-EDX and mercury porosimetry analysis. In vitro cytotoxicity testing of porous HA was conducted by MTT method using vero cells. Porous HA has porosity on the interval 62.79 to 69.67% and compressive strength on the interval 1.53 to 3.71 MPa. Optimal porous HA has porosity is 62.79% with compressive strength is 3.71 MPa. Mercury porosimetry analysis showed that optimal porous HA has interconnective porosity up to 88.25% with pore size on the interval 0.05-355 μm and median pore is 52.64 μm. There was no significantly difference in the death percentage of vero cells caused HA powder and optimal porous HA (p= 0.158) but concentration of optimal porous HA were significantly effect on the percentage of vero cells death (p=0.003).

scholarly journals Wood Bottom Ash and GeoSilex: A By-Product of the Acetylene Industry as Alternative Raw Materials in Calcium Silicate Units

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 489
Author(s):  
Manuel Angel Felipe-Sesé ◽  
Luis Pérez-Villarejo ◽  
Eulogio Castro ◽  
Dolores Eliche-Quesada
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Calcium Silicate ◽  
Building Materials ◽  
Raw Materials ◽  
Bottom Ash ◽  
Weight Ratio ◽  
Experimental Program ◽  
Environmental Costs

The main objective of this research was to obtain calcium silicate units from alternative raw materials, such as the bottom ashes from the combustion of wooden boards (WBA), as a source of silica, and GeoSilex (G), a by-product with low energy and environmental costs generated in the manufacture of acetylene, as a source of lime. Once the raw materials were physically, mineralogically and chemically characterized, calcium silicate units were obtained by mixing different amounts of WBA residue (90–20 wt%) and G by-product (10–80 wt%). The mixtures were compressed at 10 MPa and cured in water for 28 days. The calcium silicate units were subjected to a wide experimental program that included the determination of physical properties (bulk density, apparent porosity and water absorption), mechanical properties (compressive strength), and thermal properties (thermal conductivity). Optimum values are obtained for calcium silicate units that contain a 1/1 WBA/G weight ratio, which have an optimal amount of SiO2 and CaO for the cementation reaction. The 50WBA-50g units have compressive strength values of 46.9 MPa and a thermal conductivity value of 0.40 W/mK. However, all calcium silicate units obtained comply with the European Standard EN 771-2: 2011 to be used as structural building materials.

scholarly journals Effect of the Bis-Dimethylamino Benzydrol Coinitiator on the Mechanical and Biological Properties of a Composite

2017 ◽  
Vol 28 (6) ◽  
pp. 744-748
Author(s):  
Bruna Fortes Bittencourt ◽  
John Alexis Dominguez ◽  
Luís Antonio Pinheiro ◽  
Paulo Vitor Farago ◽  
Elizabete Brasil dos Santos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Biological Properties ◽  
In Vitro Cytotoxicity ◽  
3T3 Fibroblasts ◽  
Post Test ◽  
Ft Ir ◽  
Fibroblastic Cells

Abstract To examine the effect of the alternative coinitiator 4,4’bis dimethylamino benzydrol (BZN) in degree of conversion (DC), mechanical and biological properties of experimental composites. The coinitiator BZN was used in three concentrations (0.2, 0.5 and 1.2%), and the coinitiator DMAEMA was used as control at the same concentrations as above. The molar concentration of camphorquinone (CQ) and coinitiators was kept constant (1:1). The composites were manipulated and submitted to microhardness test (VHN), flexural and compressive strength (in MPa), elastic modulus (GPa), DC (FT-IR) and in vitro cytotoxicity (against 3T3 fibroblastic cells) of the experimental resins. Data were subjected to two-way ANOVA and Tukey post-test (α=0.05). The experimental composite resin with BZN showed higher DC values compared to control DMAEMA groups. For the mechanical properties, microhardness values were higher in BZN groups; flexural strength and elastic modulus were similar between all the groups. Compressive strength for groups BZN0.5 and DMAEMA0.5 were not statistically different, being the lowest values attributed to group BZN0.2. The experimental resins with BZN and DMAEMA were considered nontoxic against 3T3 fibroblasts. The inclusion of the coinitiator BZN in experimental composites was considered nontoxic against 3T3 fibroblast cells, without compromising DC and mechanical properties.

scholarly journals Laboratory testing of hemolytic properties of materials that come in contact with blood: Comparative application testing method’s two variants according to the standard ASTM F756 in accordance with ISO 10993-4

2010 ◽  
Vol 64 (2) ◽  
pp. 149-156
Author(s):  
Katarina Pavlovic ◽  
Vojislav Bozanic ◽  
Jasna Stanojevic ◽  
Vesna Milicevic ◽  
Bojan Ilic
Keyword(s):  
Incubation Time ◽  
Direct Contact ◽  
Raw Materials ◽  
Osmotic Shock ◽  
Negative Control ◽  
The Other ◽  
Raw Material ◽  
Comparative Approach ◽  
Laboratory Equipment

The presence of hemolytic material in contact with blood may produce increased levels of blood cell lysis and increased levels of plasma hemoglobin. This may induce toxic effects or other effects which may stress the kidneys or other organs. In this paper two variants of in vitro method and obtained results? comparison were presented for testing of hemolytic properties of six raw materials (Polipropylene Moplen EP 540 P, Policarbonate colorless 164 R-112, Policarbonate brown 164 R-51918, Polietylene NG 3026 K, Polietylene NG - Purell GB 7250, Polietylene VG - Hiplex 5502) for medical device manufacturing and one raw material (Polietylen NG granulate) used for infusion solutions?s plastic bottles manufacturing. One of method?s variants relies on raw material direct contact with swine blood and the other on extract of the material contact with swine blood. Both method?s variants imply reading of the absorbance of the supernatant after tubes were incubated and centrifuged. According to values obtained and using the standard curve free hemoglobin concentration is determined and based on this percentage hemolysis of raw material. Positive and negative controls were used in both variants where water for injection (WFI) was used as positive control in which partial or complete hemolysis of erythrocytes occurs due to osmotic shock and phosphate buffer saline was used as negative control with no hemolytic property. In this paper comparison of results obtained by both method?s variants for testing of seven raw materials was presented, while these conclusions can not be used neither for all materials, nor for all applications without preliminary testing using both variants and then choosing more sensitive and more reliable one. It was shown and stated in the paper as well that incubation time being 3, 15 or 24 h, had no impact on the variant?s with direct contact sensitivity. This comparative approach was used for drawing conclusions in terms of suitability for application of one or the other method?s variant, as well as for defining relevant incubation time and finally for choosing more sensitive and more reliable variant for assessment of hemolytic properties of raw materials. Variant with direct contact was chosen from the aspect of less complexity regarding necessary laboratory equipment which makes it economically more favorable and fit for the purpose.

Sign in / Sign up

Export Citation Format

Share Document