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 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 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 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).

scholarly journals Physicochemical and in vitro bioactivity studies of bioactive glasses in the SiO2-CaO-MgO-P2O5, SiO2-Na2O-CaO-P2O5 and SiO2-Na2O-CaO-MgO-P2O5 systems

2020 ◽  
Vol 10 (5) ◽  
pp. 492
Author(s):  
Smaiel Herradi ◽  
Sara Bouhazma ◽  
Sanae Chajri ◽  
Imane Adouar ◽  
Souad Rakib ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Sol Gel ◽  
Energy Dispersive ◽  
In Vitro Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vitro Test ◽  
Diffraction Patterns ◽  
The One

<p>Glasses in the quaternary and quinary system SiO<sub>2</sub>-CaO-MgO-P<sub>2</sub>O<sub>5 </sub>(SCMP), SiO<sub>2</sub>-Na<sub>2</sub>O-CaO-P<sub>2</sub>O<sub>5 </sub>(SNCP) and SiO<sub>2-</sub>Na<sub>2</sub>O-CaO-MgO-P<sub>2</sub>O<sub>5 </sub>(SNCMP), have been prepared by using the sol-gel technique. Investigations of structural and bioactive properties of these glasses have been undertaken by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The <em>in vitro</em> bioactivity was assessed by determining the changes in surface morphology and composition after soaking in simulated body fluid (SBF) for up to 30 days at 37°C. X-ray diffraction patterns indicated the formation of hydroxycarbonated apatite layer (HCA) after only one hour for SNCMP glass and after four days for SCMP and SNCP glasses. Furthermore, observed bands of FTIR spectra confirmed the growth of HCA layer during in vitro test.</p><p>Moreover, the dissolution rate has been investigated using energy-dispersive X-ray spectroscopy. The observed EDS patterns confirmed the growth of HCA layer on all samples surfaces during <em>in vitro</em> analysis. On the one hand, we report the existence of Na<sub>2</sub>Ca<sub>2</sub>Si<sub>3</sub>O<sub>9 </sub>(that couple good mechanical strength with satisfactory biodegradability) as a single crystalline phase in the SNCP glass when calcined at 600°C. On the other hand, we have noticed that the coexistence of magnesium and sodium both enhanced the dissolution rate and hindered the crystallization in the SNCMP glass at 600°C.</p>

THE STUDY ON GRANTING BIOACTIVITY OF Ti ALLOY BY SURFACE TREATMENT

2010 ◽  
Vol 17 (02) ◽  
pp. 153-157 ◽  
Author(s):  
N. R. HA ◽  
Z. X. YANG ◽  
G. C. KIM ◽  
K. H. HWANG ◽  
D. S. SEO ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Body Fluid ◽  
Surface Effect ◽  
In Vitro Test ◽  
Ti Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Surface ◽  
Vitro Test

Titanium alloys are superior of biocompatibility, mechanical properties and chemical stability. The biocompatibility of Ti alloy is related to the surface effect between human tissue and implant. Therefore, the purpose of this study is to investigate the bioactivity of Ti alloy by alkali and acid chemical surface treatment; and the biocompatibility of Ti alloy was evaluated by in vitro test. Higher bone-bonding ability and bioactivity of the substrate were obtained by the formation of apatite layers on the Ti alloy in simulated body fluid. The microstructures of apatite layer were investigated by scanning electron microscope (SEM) and the formed phases were analyzed with X-ray diffraction (XRD).

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 Clinical Evaluation of an in Vitro Test for Radiosensitivity of Leukemic Lymphocytes

Blood ◽  
1962 ◽  
Vol 20 (4) ◽  
pp. 432-442 ◽  
Author(s):  
ROBERT SCHREK ◽  
STANLEY L. LEITHOLD ◽  
IRVING A. FRIEDMAN ◽  
WILLIAM R. BEST
Keyword(s):  
Survival Time ◽  
Median Survival ◽  
Median Survival Time ◽  
Leukocyte Count ◽  
In Vitro Test ◽  
X Rays ◽  
X Ray ◽  
Leukocyte Counts ◽  
Vitro Test

Abstract A recently developed slide-chamber method was used to test the radiosensitivity of blood lymphocytes from 80 patients with chronic lymphocytic or lymphosarcoma-cell leukemia. The objective of this study was to determine whether these in vitro tests on sensitivity to x-rays had any clinical significance. Two objective criteria were used to measure the clinical reactions of the leukemic patients. The first was the duration of survival of patients following the in vitro test. The second was the minimal leukocyte count of a patient following x-ray therapy; the minimal count was expressed as a percentage of the count before therapy. The in vitro radiosensitivity was measured by the 10 per cent survival time of lymphocytes irradiated with 1000 r. Blood lymphocytes from non-leukemic individuals were highly radiosensitive with indices of 1.1 to 2.2 days. In initial tests, the lymphocytes of 61 leukemic patients had the same high sensitivity to x-rays as lymphocytes from non-leukemic individuals. In contrast, the lymphocytes of 19 leukemic patients were radioresistant to irradiation with indices of 2.5 to 11 days. The 61 patients with radiosensitive lymphocytes had a median survival time of 22 months after the in vitro test. In contrast, the 19 patients with radioresistant lymphocytes had a median survival time of only 4 months. Clinical x-ray therapy caused a greater decline in leukocyte counts in patients with radiosensitive lymphocytes than in those with radioresistant cells. A significant index of 0.60 was obtained for the correlation of in vitro radiosensitivity of lymphocytes and the in vivo decrease in leukocyte counts of patients after x-ray therapy. It is concluded that an in vitro finding of radioresistant lymphocytes is correlated with a poor response of the leukocyte count to x-ray therapy and a short survival time of the patient.

In Vitro Study of Microplasma Sprayed Hydroxyapatite Coatings in Simulated Body Fluid

2009 ◽  
Vol 79-82 ◽  
pp. 815-818 ◽  
Author(s):  
Qiu Ying Zhao ◽  
Ding Yong He ◽  
Xiao Yan Li ◽  
Jian Min Jiang
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Carbonate Apatite ◽  
In Vitro Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Hydroxyapatite Coatings ◽  
Vitro Test

Hydroxyapatite (HA) coatings were deposited onto Ti6Al4V substrate by microplasma spraying (MPS) in the current research. The morphology, phase compositions, and percentage of crystallinity of the coatings were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction. An in vitro evaluation by soaking the coatings in simulated body fluid (SBF) for up to 14 days was conducted aiming at the evaluation of their bioactivity. Results from the present investigation suggest that microplasma sprayed HA coatings exhibited certain roughness, pores, and microcracks. Thermal decomposition existed in the coatings where HA, α-TCP，β-TCP, amorphous phases, and CaO-exclusive impurities were observed. The in vitro test indicated that HA coatings deposited by MPS possessed better bioactivity and stability. A layer of carbonate-apatite covered most of the coating surface, which did not exhibit significant spalling after incubation in SBF.

Preparation of the Nano-Hydroxyapatite/Chitosan/Konjac Glucomannan Composite as a Novel Degradable Drug Delivery System

2008 ◽  
Vol 569 ◽  
pp. 357-360
Author(s):  
Gang Zhou ◽  
Yu Bao Li ◽  
Soo Wohn Lee
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Konjac Glucomannan ◽  
In Vitro Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Vitro Test

Nano-hydroxyapatite (n-HA)/chitosan (CS)/konjac glucomannan (KGM) composite was prepared by integrating composition and molding. Then, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the physical, chemical and degradable properties of the composite before and after in simulated body fluid (SBF). Moreover, study in vitro test for drug delivery revealed that the amount of released pentoxifylline (1-[5-oxohexyl]-3,7-dimethylxanthine)(PTX) reached a plateau and equaled 80% of the drug loaded in an implant. The newly develop n-HA/CS/KGM composite may serve as a good degradable biomaterial for implantable drug delivery system (IDDS) in bone tissue engineering.

Sign in / Sign up

Export Citation Format

Share Document