scholarly journals In vitro bioactivity of 70 wt.% SiO2 — 30 wt.% CaO sol-gel glass, doped with 1, 3 and 5 wt.% NbF5

2012 ◽  
Vol 10 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Lachezar Radev ◽  
Katia Hristova ◽  
Valery Jordanov ◽  
Maria Fernandes ◽  
Isabel Salvado
Keyword(s):  
Sol Gel ◽  
Active Role ◽  
In Vitro Test ◽  
In Vitro Bioactivity ◽  
Soaking Time ◽  
Vitro Test ◽  
Sbf Solution ◽  
Gel Glasses ◽  
Static Conditions

AbstractThe 70SiO2-30CaO (wt.%) sol-gel glasses doped with 1, 3 and 5 NbF5 (wt.%) were prepared via polystep sol-gel route. The synthesized glasses were characterized by XRD, FTIR and SEM. Changes in 1.5 SBF solutions were measured by ICP-AES. XRD of the glasses stabilized at 700°C for 6 hours proved the presence of niocalite. FTIR was consistent with XRD data. The in vitro bioactivity study of all glasses prepared were carried out by soaking in 1.5 simulated body fluid (1.5 SBF) at 37°C for 6 and 12 days in static conditions. The FTIR reveals the formation of A-type and B-type carbonate containing hydroxyapatite (CO3HA) layer. Changes in 1.5 SBF solutions, after 6 days of soaking, show that the Ca concentration increased significantly, compared to the initial Ca content in the 1.5 SBF solution before in vitro test. After 12 days of immersion, the Ca concentration decreased, i.e., the formation of HA phase consumed Ca from 1.5 SBF solution. For all soaking times, the concentration of P is much lower than that the used 1.5 SBF. Based on these results we suggest that Ca and P play an active role in the future of the glasses. SEM depicts that the different morphology of hydroxyapatite can be formed as a function of soaking time.

scholarly journals In vitro bioactivity of Polyurethane/85S Bioglass composite scaffolds

2013 ◽  
Vol 11 (9) ◽  
pp. 1439-1446 ◽  
Author(s):  
Lachezar Radev ◽  
Darina Zheleva ◽  
Irena Michailova
Keyword(s):  
Sol Gel ◽  
Spherical Particles ◽  
Polymerization Reaction ◽  
In Vitro Test ◽  
In Vitro Bioactivity ◽  
Before And After ◽  
Vitro Test ◽  
Sbf Solution ◽  
Static Conditions

AbstractIn the present work Polyurethane (PU)/Bioglass (BG) composite materials were synthesized with different content of BG (10 and 20 mol.%) as filler. The 85S Bioglass was synthesized via polystep sol-gel method. The chemical composition of BG is 85SiO2-10CaO-5P2O5 (wt.%). The synthesis of PU was carried out by a two-step polyaddition reaction. The 85S BG was added in situ during the polymerization reaction. In vitro bioactivity of the prepared composites was examined in the presence of 1.5 SBF for 7 days in static conditions. The structure of synthesized PU/BG composites before and after in vitro test was determined by XRD, FTIR and SEM. XRD of the samples before in vitro test proved that the phase of γCa2P2O7 in the PU/20BG is visible. FTIR revealed the presence of urethane bond between OH-(from BG) and NCO groups (from PU). Based on FTIR results after in vitro test in 1.5 SBF solutions, A/B-carbonate containing hydroxyapatite (CO3HA) was formed. XRD proved that HA was formed on the surface of the samples, but Ca2P2O7 does not undergo any changes in the 1.5 SBF solution. SEM depicted the nano-HA agglomerated in spherical particles after immersion in 1.5 SBF for 7 days.

scholarly journals Influence of thermal treatment on the structure and in vitro bioactivity of sol-gel prepared CaO-SiO2-P2O5 glass-ceramics

2014 ◽  
Vol 8 (3) ◽  
pp. 155-166 ◽  
Author(s):  
Lachezar Radev
Keyword(s):  
Thermal Treatment ◽  
Calcium Silicate ◽  
Sol Gel ◽  
Glass Ceramics ◽  
In Vitro Test ◽  
In Vitro Bioactivity ◽  
X Ray ◽  
Vitro Test ◽  
Sbf Solution

Nowadays there is a substantial practical interest in the in vitro bioactivity of calcium silicate phosphate (CSP) glass-ceramics and carbonate apatite (CO3HA) formation on their surfaces after in vitro test in simulated body fluid (SBF). The main purpose of the presented article is the evaluation of the chemical composition of the gel with nominal composition 70.59 CaO:28.23 SiO2:1.18 P2O5 (mol.%) on the structure, crystallization behaviour and in vitro bioactivity in SBF solution for 14 and 28 days. The prepared glass-ceramics have been synthesized via a polystep sol-gel method. The structure of the obtaining samples was studied by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). After thermal treatment of the samples XRD confirmed the presence of ?-Ca2SiO4 and Ca15(PO4)2(SiO4)6, and indicated that at 1500?C Ca15(PO4)2(SiO4)6 becomes predominant phase. FTIR revealed the presence of all characteristics bands for calcium silicate phosphate (CSP) bonds. SEM monitors the presence of particles with different morphology. After in vitro test in SBF, FTIR depicted that B-type carbonate containing hydroxyapatite (CO3HA) is preferentially formed on the immersed glass-ceramics. SEMof the precipitated layers showed the presence of HA spheres. The changes in SBF solution after soaking the samples were recorded by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

scholarly journals A novel ceramic material with medical application

2008 ◽  
Vol 2 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Joanna Podporska ◽  
Marta Błażewicz ◽  
Barbara Trybalska ◽  
Łukasz Zych
Keyword(s):  
Body Fluid ◽  
Crystallization Process ◽  
Sol Gel ◽  
Medical Application ◽  
In Vitro Test ◽  
Glass Crystallization ◽  
Complex Shapes ◽  
Different Temperatures ◽  
Vitro Test

Until now the basic methods used in manufacturing of wollastonite have been chemical (melting together with glass crystallization process, chemical coprecipitation) and sol - gel methods. A new and promising way of wollastonite fabrication is controlled pyrolysis of polysiloxane precursors with inorganic fillers. Heat treatment of such mixtures leads to the formation of wollastonite-containing ceramics already at about 1000?C. This is a relatively inexpensive and efficient method which enables to obtain complex shapes of the samples. The aim of this work was to obtain sintered, wollastonite-containing bioceramics and determine its bioactive features. Samples were sintered at three different temperatures: 1000, 1100 and 1200?C. Then the bioactivity of the wollastonite-containing ceramics was investigated by the ?in vitro? test in simulated body fluid. On the basis of the achieved results, it can be assumed that the obtained material possesses bioactive features.

scholarly journals Organic/Inorganic bioactive materials Part III: in vitro bioactivity of gelatin/silicocarnotite hybrids

2009 ◽  
Vol 7 (4) ◽  
pp. 721-730 ◽  
Author(s):  
Lachezar Radev ◽  
Maria Fernandes ◽  
Isabel Salvado ◽  
Daniela Kovacheva
Keyword(s):  
Calcium Phosphate ◽  
Hybrid Materials ◽  
Calcium Phosphates ◽  
Ceramic Powder ◽  
Structure Evolution ◽  
In Vitro Test ◽  
In Vitro Bioactivity ◽  
Bioactive Materials ◽  
Vitro Test

AbstractIn this work we present our experimental results on synthesis, structure evolution and in vitro bioactivity assessment of new gelatin/silicocarnotite hybrid materials. The hybrids were obtained by diluting gelatin (G) and silicocarnotite (S) ceramic powder with G:S ratios of 75:25 and 25:75 wt.% in hot (40°C) water. The hybrids were characterized using XRD, FTIR, SEM/EDS and XPS. FTIR depicts that the “red shift” of amide I and COO− could be attributed to the fact that the gelatin prefers to chelate Ca2+ from S. The growth of calcium phosphates on the surface of the hybrids synthesized and then immersed in 1.5 SBF for 3 days was studied by using of FTIR, XRD and SEM/EDS. According to FTIR results, after an immersion of 3 days, A and B-type CO3HA can be observed on the surface. XRD results indicate the presence of hydroxyapatite with well defined crystallinity. SEM/EDS of the precipitated layers show the presence of CO3HA and amorphous calcium phosphate on the surface of samples with different G/S content when immersed in 1.5 SBF. XPS of the G/S hybrid with 25:75 wt.% proved the presence of Ca-deficient hydroxyapatite after an in vitro test for 3 days.

scholarly journals Evaluation of RSA set-up from a clinical biplane fluoroscopy system for 3D joint kinematic analysis

Joints ◽  
2016 ◽  
Vol 04 (02) ◽  
pp. 121-125 ◽  
Author(s):  
Tommaso Bonanzinga ◽  
Cecilia Signorelli ◽  
Marco Bontempi ◽  
Alessandro Russo ◽  
Stefano Zaffagnini ◽  
...  
Keyword(s):  
Rigid Body ◽  
Kinematic Analysis ◽  
In Vitro Test ◽  
Flexion Extension ◽  
Vitro Test ◽  
Set Up ◽  
Static Conditions ◽  
Biplane Fluoroscopy

Purpose: dinamic roentgen stereophotogrammetric analysis (RSA), a technique currently based only on customized radiographic equipment, has been shown to be a very accurate method for detecting threedimensional (3D) joint motion. The aim of the present work was to evaluate the applicability of an innovative RSA set-up for in vivo knee kinematic analysis, using a biplane fluoroscopic image system. To this end, the Authors describe the set-up as well as a possible protocol for clinical knee joint evaluation. The accuracy of the kinematic measurements is assessed. Methods: the Authors evaluated the accuracy of 3D kinematic analysis of the knee in a new RSA set-up, based on a commercial biplane fluoroscopy system integrated into the clinical environment. The study was organized in three main phases: an in vitro test under static conditions, an in vitro test under dynamic conditions reproducing a flexion-extension range of motion (ROM), and an in vivo analysis of the flexionextension ROM. For each test, the following were calculated, as an indication of the tracking accuracy: mean, minimum, maximum values and standard deviation of the error of rigid body fitting. Results: in terms of rigid body fitting, in vivo test errors were found to be 0.10±0.05 mm. Phantom tests in static and kinematic conditions showed precision levels, for translations and rotations, of below 0.1 mm/0.2º and below 0.5 mm/0.3º respectively for all directions. Conclusions: the results of this study suggest that kinematic RSA can be successfully performed using a standard clinical biplane fluoroscopy system for the acquisition of slow movements of the lower limb. Clinical relevance: a kinematic RSA set-up using a clinical biplane fluoroscopy system is potentially applicable and provides a useful method for obtaining better characterization of joint biomechanics.

In Vitro Bioactivity of AISI 316L Stainless Steel Coated with Hydroxyapatite-Seeded 58S Bioglass

MRS Advances ◽  
2019 ◽  
Vol 4 (57-58) ◽  
pp. 3133-3142 ◽  
Author(s):  
Jorge López-Cuevas ◽  
Juan Carlos Rendón-Angeles ◽  
Juan Méndez-Nonell ◽  
Héctor Barrientos-Rodríguez
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Sol Gel ◽  
Aisi 316L ◽  
In Vitro Bioactivity ◽  
Aisi 316L Stainless Steel ◽  
Gel Technique ◽  
Static Conditions ◽  
Steel Substrates

ABSTRACTAISI 316L stainless steel substrates were coated with hydroxyapatite [HAp, Ca10(PO4)6(OH)2]-seeded 58S bioglass, and then their in vitro bioactivity was evaluated by soaking in a simulated body fluid (SBF). The bioglass was prepared via the sol-gel technique and nanometric HAp single crystals were obtained by hydrothermal synthesis. The coatings had bioglass/HAp weight ratios of 100/0, 90/10 or 80/20. The in vitro bioactivity tests were carried out under static conditions at 37 °C and pH = 7.25, for time periods ranging from 1 to 21 days. The results showed that the HAp-seeding significantly accelerates the formation of a HAp layer at the bioglass-coated steel surface during the bioactivity tests.

Effect of magnesium content on the in vitro bioactivity of CaO-MgO-SiO2-P2O5 sol-gel glasses

1999 ◽  
Vol 9 (2) ◽  
pp. 515-518 ◽  
Author(s):  
M. Vallet-Regí ◽  
A. J. Salinas ◽  
J. Román ◽  
M. Gil
Keyword(s):  
Sol Gel ◽  
Magnesium Content ◽  
In Vitro Bioactivity ◽  
Gel Glasses

scholarly journals Collagen/silicocarnotite composites, cross-linked with chondroitin sulphate: In vitro bioactivity

2011 ◽  
Vol 5 (3) ◽  
pp. 161-170 ◽  
Author(s):  
Lachezar Radev ◽  
Vladimir Hristov ◽  
Irena Michailova ◽  
Maria Fernandes ◽  
Isabel Salvado
Keyword(s):  
Inductively Coupled Plasma ◽  
Chondroitin Sulphate ◽  
Atomic Emission ◽  
Red Shift ◽  
Structure Evolution ◽  
In Vitro Test ◽  
In Vitro Bioactivity ◽  
Before And After ◽  
Vitro Test

In this work we present the experimental results on synthesis, structure evolution and in vitro bioactivity of collagen- silicocarnotite-chondroitin sulphate composites. The obtained samples were synthesised by mixing collagen (C) and silicocarnotite (S) powder with C:S ratio of 75:25 and 25:75 wt.% in the presence of chondroitin sulphate (ChS). Collagen was diluted in 5M CH3COOH before mixing. The obtained materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) before and after in vitro test in 1.5 simulated body fluid. XRD of synthesized samples showed that before immersion carbonate containing hydroxyapatite (CO3HA) were formed in situ in the composites. FTIR depicts the presence of HPO4 2- and the 'red shift' of COO- and SO3 - from ChS was also observed. This 'red shift' could be attributed that the ChS prefers to chelate Ca2+ from partially dissolved S powder. SEM of the prepared samples show the presence of nanosized hydroxyapatite (HA) whiskers and flower-like HA assemblies. After in vitro test, XRD proved the presence of HA with well-defined crystallinity. According to the FTIR results B-type CO3HA can be observed. SEM of the precipitated layers show the presence of HA spheres. Inductively coupled plasma atomic emission spectroscopy results lead to a conclusion that after in vitro test of the prepared composites silicon containing carbonate substituted hydroxyapatite (Si-CO3HA) may be formed on the surface of the immersed samples.

scholarly journals Sol-gel bioactive glass-ceramics Part II: Glass-ceramics in the CaO-SiO2-P2O5-MgO system

2009 ◽  
Vol 7 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Lachezar Radev ◽  
Vladimir Hristov ◽  
Irena Michailova ◽  
Bisserka Samuneva
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Static Condition ◽  
Ceramic Materials ◽  
Molar Ratio ◽  
In Vitro Test ◽  
X Ray Diffraction ◽  
Vitro Test ◽  
Good Agreement

AbstractCeramics, with basic composition based on the CaO-SiO2-P2O5-MgO system with different Ca+ Mg/P+Si molar ratio (R), were prepared via polystep sol-gel technique. The structure of the obtained ceramic materials has been studied by XRD, FTIR spectroscopy, and SEM. X-ray diffraction showed the presence of akermanite and HA for the sample with R = 1.68 and Mg substituted β-TCP and silicocarnotite for the sample with R = 2.16, after thermal treatment at 1200°C/2 h. The obtained results are in good agreement with FTIR. In vitro test for bioactivity in static condition proved that the carbonate containing hydroxyapatite (CO3HA) can be formed on the surface of the synthesized samples. CO3HA consisted of both A- and B-type CO 32− ions. SEM micrographs depicted different forms of HA particles, precipitated on the surface after soaking in 1.5 simulated body fluid (SBF).

The 1100 C Thermoluminescence Peak as a Probe in Bioactivity Study of the 58S Sol-Gel Bioactive Glass

2011 ◽  
Vol 493-494 ◽  
pp. 49-54 ◽  
Author(s):  
George S. Polymeris ◽  
Ourania Menti Goudouri ◽  
Konstantinos M. Paraskevopoulos ◽  
George Kitis
Keyword(s):  
Bioactive Glass ◽  
Time Scale ◽  
Immersion Time ◽  
Sol Gel ◽  
Glow Peak ◽  
In Vitro Bioactivity ◽  
Effective Application ◽  
Peak Intensity ◽  
Sbf Solution

Results of the present study provide strong indications towards the effective application of the 110oC Thermoluminescence (TL) peak in discriminating between different bioactive responses for the case of the 58S bioactive glass. The in vitro bioactivity of this glass in the form of powder in SBF solution was tested for various immersion times, ranging between 0 and 6 days. This TL peak is ubiquitously present in all 58S samples, for all immersion times. The intensity of the110oC TL peak was proven to be very sensitive to the different bioactive responses, indicating a strongly decreasing pattern with increasing immersion time in SBF, easily identifying thus the loss of silica. This loss is reflected to the decrease of the 110oC TL peak intensity, which appears to be fast even for the shorter immersion times. The 110oC TL glow peak intensity and sensitization could also be yielding a time scale regarding the beginning of some among the several stages included in the bioactivity sequence.

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