Bioceramics Development and Applications

Objective. The aim of the present study is to prepare a 3D porous silk fibroin scaffold with a hierachical structure that can meet the demands for bone tissue engineering. Materials and Methods. 3D fibroin scaffold was prepared by the methods of partial dissolution in acid solution and freeze drying fibroin solution. Results. The nets were composed of a mesh of randomly oriented fibers that ranged between 10 μm and 30 μm in diameter. Branchpoints and three dimensional open spaces were distributed throughout the structure with an average pore size of about 177.9 ± 40.0 μm. Conclusion. With the methods of non-woven silk fibroin net preparation and frozen-dried technics, it is possible to prepare a 3D porous silk fibroin scaffold with hierachical fine structure.

In an ideal synthetic bone substitute, the material should be partly or totally resorbed with time and replaced by host bone. A combination of calcium-phosphate (CaP) and calcium sulphate (CaS) will lead to resorption of the sulphate and allow bone ingrowth. Chondroadherin (CHAD) as a noncollagenous cartilage protein may play an important role in the regulation of chondrocyte growth and proliferation. Adding CHAD to a bone substitute may play a role in speeding up the bone integration. To explore the release of CHAD, pellets of material were placed in PBS for up to 14 days. Supernatant absorbance was measured in a UV-Vis spectrophotometer. Results showed a steady release of CHAD most notable especially within the first hour. To explore bone integration with the combined material, pellets were implanted in a bone harvest chamber bilaterally in rabbit tibia. After 2 and 3 weeks, tibiae were harvested and prepared for histology evaluation. Results showed that the number of osteoclast cells was higher in specimens containing CHAD than those without, but there is no significant difference. A trend of increasing new bone area and new bone contacting implanted material was found at 2 weeks and at 3 weeks with CHAD. Changes of dosage and material composition should be considered in further studies.

The microporous materials, Zeolite A and ZSM-5 were hydrothermally synthesized and their H₂S adsorption was studied. The obtained samples were put into a separable glass flask filled with H₂S gas, and the change in concentrations of H₂S was measured for 1–48 h at rt. Then the samples were taken out and put into a pyrolysis plant attached to gas chromatography-mass spectroscopy to determine the amount of H₂S desorbed from samples. The amount of H₂S adsorbed on Zeolite A was found to be larger than that on ZSM-5. That is 46% of H₂S was desorbed from Zeolite A when heated at 400°C, while 24% of H₂S was desorbed from ZSM-5. The adsorption/desorption behavior of H₂S from zeolite materials could be interpreted by the electrostatic interaction between H₂S and adsorbent.

We developed a novel thermal spraying technology for a silver-containing hydroxyapatite (Ag-HA) coating with antibacterial activity to reduce the incidence of implant-associated infections. In this study, we determined the concentration of Ag ions that show antibacterial activity in fetal bovine serum (FBS) and antibacterial activity of the Ag-HA coating in FBS. The minimum inhibitory concentration (MIC) of Ag ions for several bacteria in FBS was in the range of 4.0–7.9 ppm. When 10 ppm Ag were added (as AgNO₃ solution), 0.01 ppm of free Ag ions was detected. As the MIC of Ag ions approached the concentration that enabled formation of free Ag ions in FBS, the antibacterial activity of added Ag can be attributed to the free Ag ions. The Ag-HA coating showed strong antibacterial activity in FBS as well; the Ag concentration in FBS was 26 ppm for the antibacterial test of the Ag-HA coating. Because the Ag-HA coating can release sufficient free Ag ions in FBS, we observed that the Ag-HA coating shows a strong antibacterial effect in the biological medium studied.

Imogolite is a naturally occurring aluminosilicate clay mineral with a nanotube structure. In this study, synthetic imogolite nanotubes were applied to cell culture and the properties as scaffold were compared with those of a conventional culture dish and the carbon nanotube scaffold. The surface characteristics of the imogolite scaffold were drastically changed with the amount of imogolite on the dish. Human osteoblast-like cells (SaOS2) on imogolite scaffolds showed a widely spreading morphology and a high functional expression. Particularly, the scaffold with the large amount of imogolite provided the suitable environments of topography, roughness, wettability and protein adsorption ability for widely spreading morphology and differentiation of osteoblasts. Imogolite retains various positive factors as scaffolds for osteoblastic proliferation and differentiation and is expected for the application to bone tissue engineering.

In this study, magnetite nanoparticles (MNPs) with series of size varying from 8nm to 103nm were synthesized by a chemical co-precipitation and an oxidation-precipitation method to aim for finding the optimum particle size which has high heating efficiency in the applied magnetic field (9.6–23.9 kA·m⁻¹, 100kHz). Their in vitro heating efficiencies in agar phantom, at a MNPs concentration of 58mg Fe·ml⁻¹, were measured in the applied field. The temperature increase (∆T) of the agar phantom at 30s was 9.3°C for MNPs of 8nm, exhibiting a high heating efficiency in a field intensity of 9.6kA·m⁻¹. The ∆T of agar was 55°C for MNPs of 24nm and 25°C for MNPs of 8nm in a field intensity of 23.9kA·m⁻¹. The excellent heating efficiency for MNPs of 24nm might be a combined effect of relaxation loss and hysteresis loss of the magnetic particles.

An inert titanium surface was treated with the BIO treatment (developed by the company Lasak, Ltd.), i.e. its surface area was increased by mechanical and chemical treatment with blasting and exposure to HCl and NaOH. The treated surface was provided with thin layers of calcium phosphate OCP (Octacalcium Phosphate) or ACP (Amorphous Calcium Phosphate) by means of precalcification (using a supersaturated SCS2 solution). In vitro tests in SBF (Simulated Body Fluid) under dynamic conditions have shown that precalcified layers have the ability to induce development of HAp (Hydroxyapatite) on the surface much faster than BIO surfaces without such layers. The OCP crystals are well adhesive but cytotoxicity tests have shown that a bioactive layer prepared in this manner is slightly toxic. The ACP prepared ultrasonically is incorporated directly into the TiO₂ gel and thus does not increase implant's dimension and moreover ACP is not toxic (confirmed by cytotoxicity tests).

Apatite-polymer hybrids have been attractive as novel bone-bonding bioactive bone substitutes with mechanical performances analogous to those of natural bone. It is shown that carboxyl group (COOH) can induce the apatite nucleation in an environment of simulated body fluid (SBF). In the present study, we fabricated porous hyaluronic acid gels abundant in COOH group and investigated their apatite formation ability in SBF. Hyaluronic acid has been attractive for bone- and cartilagerepairing materials due to high biological compatibility. We attempted the preparation of bioactive organic-inorganic hybrids from Hyaluronic acid. It has been attractive for bone- and cartilage-repairing materials due to high biological compatibility. It is known that divinyl sulfone is a candidate of cross-linker to bridge the hydroxyl groups. The hydroxyl group of hyaluronic acid side chains were bridged by divinyl sulfone. Porous hyaluronic acid gels stable in aqueous environment were obtained by appropriate crosslinking. They formed the apatite on their surfaces in SBF, when they were priorly treated with CaCl₂ aqueous solution. In addition, trehalose, a kind of disaccharide, is found to increase the pore size of the porous hyaluronic acid. This suggests that the pore size and porosity can be controlled by addition of trehalose during fabrication of the scaffolds.

Many micro pores were formed on the surface of a titanium (Ti) plate by sulfuric acid treatment, then apatite nuclei were precipitated in the pores of the Ti plate by direct heating of the plate by using electromagnetic induction in a simulated body fluid (SBF). When the Ti plate was soaked in SBF, amorphous calcium phosphate thin film covered the whole surface within 6 h and it grew into hydroxyapatite within 12 h. The hydroxyapatite layer showed high adhesive strength to the Ti plate due to a mechanical interlocking effect between hydroxyapatite grown in the micro pores and the Ti plate.

Synthetic hydroxyapatite was modified with zinc and strontium by two methods: ion exchange and co‑precipitation synthesis. Hydroxyapatite and metal modified hydroxyapatite samples were characterized by XRD, ICP-OES, and FTIR-DRS. BSA adsorption experiments were accomplished during 24 hours using 1.0 mg/mL of protein. UV spectrometry was used to quantify the protein at 278 nm. The results suggest that metal presence on the surface or in the bulk of hydroxyapatite improves the protein adsorption efficiency. FTIR-DRS showed that the protein main secondary structure α-Helix is involved in the adsorption process.

This study proposed a new strategy for preparing self-assembling one-dimensional HAp nanorods into organized superstructures. We employed glass of a few specific compositions in the system Na₂O-CaO-SiO₂ because it may yield Si-OH groups on the surface when soaked in an aqueous system, and their formation is one of the key factors to induce apatite nucleation. A nanometer-scale rod array of HAp having preferred orientation to the c-axis was successfully prepared simply by soaking the soda-lime silica glass substrates in Na₂HPO₄ aqueous solution at 80°C. Those HAp rods grew up perpendicularly to the glass surface, and the crystallites covered glass surface uniformly, resulting in "dental enamel-like" rod array structure. The present procedure is significant as it allows to design biomimetic materials and therapeutic agents with applicable both the biomedical and material science fields because the nano-textured HAp crystals exhibit a hierarchical architecture and may provide specific cell attachment and proliferation with controlled planes of growth and nano- and micrometer-scale topography.

Discs of poly carbonate urethane (PCU) were coated with a thin layer of calcium phosphate (CaP) by a biomimetic process at temperatures of 28°C and 37°C. The coating morphology was analyzed by SEM. Contact angle analysis was used to assess surface wettability. Human osteoblasts (HOBs) were cultured on uncoated and CaP-coated PCU discs for up to 14 days. Cell metabolism, structure, and morphology were analyzed and compared with the wettability of each sample group. HOBs proliferated and grew on uncoated and CaP-coated samples, but a greater cell metabolism was observed for uncoated samples at early time points in cell culture. A more even dispersion of HOBs across the disc surface, attributable to the increased surface wettability, was seen for CaP-coated samples.

First, electrospinning of colloidal solution consisting of titanium isopropoxide/poly(vinyl acetate) zinc nanoparticles has been achieved to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 600°C has been revealed to produce TiO₂ nanofibers containing ZnO nanoparticles; ZnO-doped TiO₂ nanofibers. The formed ZnO nanoparticles have been exploited as seeds to outgrow ZnO branches around the TiO₂ nanofibers using a hydrothermal technique. As anode in lithium ion battery, the prepared nanostructure exhibited a high rate capacity of 1232mAhg⁻¹.

Bioceramics based on calcium phosphate have been widely used due to their excellent biocompatibility and bioactivity as well as chemical composition. Sponge replica method has been developed because of its interconnected pores which are similar to cancellous bone. Porous Biphasic Calcium Phosphate (BCP) scaffold was fabricated with the synthesized powder by the replica method. BCP slurry was coated 3 times and then PU was burnt out at 800°C. The scaffolds were prepared infiltrated with PCL slurry and sintering at 1200°C for 3 hours to improve the compressive strength. Bending strength and relative density were measured. Microstructures of the composites were observed using SEM. The biocompatibility and one cell morphology of the fabricated porous body were investigated by MTT assay and SEM observation.

Porous titanium (Ti) metal with a structure similar to that of human cancellous bone was fabricated by selective laser melting (SLM) process. SEM observation showed that the core part of the walls of the porous body was completely melted by the laser beam and weakly bonded with small Ti particles on its surface. These Ti particles were joined with the core part by heating above 1000°C, with remaining micro cavities on their surfaces. Tensile strength of the as-prepared solid rod was 530MPa and gradually decreased with increasing temperatures to 400MPa at 1300°C, whereas its ductility increased with increasing temperatures. NaOH treatment formed fine network structure of sodium hydrogen titanate (SHT) on the walls of the porous Ti metal. The SHT was transformed into hydrogen titanates by HCl treatment and finally anatase and rutile by the heat treatment. Thus treated porous Ti metal formed apatite on its surface in simulated body fluid (SBF) within 3 days.

In the present study, to evaluate the effect of pore size on bone ingrowth, we fabricated lotus stem-type titanium implants each with 4 square holes (diagonal length: 500, 600, 900 and 1200μm) by using the rapid prototyping process with selective laser melting. These were then subjected to chemical and heat treatments to induce bioactivity. There were significant differences between bone ingrowth on the bioactive-treated and untreated implants. There were no significant differences for bone ingrowth among all holes in both implants. However, in both implants, the 1200-μm was found to be the best for bone invasion in the early stages of growth. On the other hand, both 500- and 600-μm were found to be suitable for bone ingrowth from 6 weeks to 26 weeks in treated implants. Thus, the simple architecture of the implants allowed effective investigation of the influence of the interconnective pore size on osteconduction.

Current work demonstrates the ability of titanium based implant surfaces to promote human osteoblasts (HOBs) differentiation and matrix production, and enhance osseointegration in vitro. Titanium surface was modified by electrospinning with sol-gel-derived hydroxyapatite (HAp) and successively calcined at various temperatures. After heat-treatment, the crystal structure of the filmed titanium oxide and sol-gel-derived crystalline HAp on titanium's surface was identified using wide-angle X-ray diffraction. Surfaces of three different samples, HAp electrospun and calcined at 600, 700 and 800°C, were investigated in terms of their ability of promotion, adherence, proliferation and differentiation of human HOB cells in vitro up to 6 days. The cells cultured on electrospun and 800°C calcined titanium surfaces showed the best results among three samples in terms of adhesion, growth and proliferation of HOBs. This work would provide a promising alternative for titanium based medical devices since it provides enhancement both on the surface and bulk properties.

Bioactivity and osteoconductivity of calcium phosphates as a function of β-tricalcium phosphate contents, that is, biodegradability, were investigated. Three calcium phosphates, pure hydroxyapatite, biphasic calcium phosphates with different mixing ratios between hydroxyapatite, and β-tricalcium phosphate (60HAp:40β-TCP and 40HAp:60β-TCP in wt.%), were synthesized through the precipitation method using calcium hydroxide and phosphoric acid as starting reactants. After drying, they were sintered at 1100°C for 3 hours, and then bioactivity and osteoconductivity tests were carried out in simulated body fluid (SBF) and calvarial defect of New Zealand white rabbits, respectively. SBF exposure resulted in the deposition of a layer of carbonate apatite crystals on the surfaces of bicalcium phosphates but not on the hydroxyapatite. New bone forming capacity of the biphasic calcium phosphate with 60HAp:40β-TCP granules was the best, whereas that of the pure HAp was the worst. To this end, it can be concluded that the calcium phosphate with moderate biodegradability is good for producing good osteoconductivity.

A biphasic calcium phosphate (BCP) powder is synthesized, mixed with various amounts of naphthalene particles, pressed and sintered at different temperatures to obtain ceramics with isolated macropores (from 3% to 52% of the specimen volume) and residual microporosity resulting from an incomplete sintering (from 2% to 45% of the ceramic matrix volume). Young's modulus is measured on a classical three-point bending setup. A good agreement is found between an existing analytical model and the experimental Young's modulus measurements, on the overall ranges of macro- and microporosity. The Young's modulus variation as a function of macroporosity is also calculated by a finite element method, by simulating the mechanical response of a periodic tri-dimensional repetition of elemental cubes containing various dispersions of macropores. The contribution of the shape and dispersion (in size and location) of the macropores on the decrease of Young's modulus as a function of porosity is simulated. Calculated trends are confirmed by experimental results.

Understanding of interactions between cells and biomaterials is a huge parameter for improving tissue engineering and regenerative medical fields. Many different materials have already been tested (including calcium phosphate ceramics) and it has been established that surface characteristic is a parameter that influences cell responses. The aim of this work was to characterize calcium phosphate discs containing various ratios of HA/β-TCP and specific microstructure. First results show that chemical composition and compression parameters modify surface materials. Secondly, cells were cultured (osteoblast-like cells MC3T3-E1) and morphology, viability, and differentiation were studied. SEM observations, mitochondrial (MTS assay), and alkaline phosphatase activity (ALP) measurements showed that osteoblasts have better viability and a higher rate of differentiation when cultured on dense surface compared to porous surface. The aim of this experiment was to contribute to the knowledge of interactions between osteoblast-like cells and microstructured calcium phosphate bioceramics pellets.

The response of human bone marrow cell to bone ash-derived hydroxyapatite (HA) and tuna bone-derived HA powders was compared. HA ceramics were prepared from the commercial bone ash and waste of tuna bone. HA powders were prepared by soaking the bone ash and tuna bone in 0.1M of NaOH solution at 80°C for 4 hours. Both powders were calcined at 800°C for 1 hour to completely remove organic and were attritor-milled for 24 hours. The bone ash-derived HA (AHA) and tuna bone-derived HA (THA) ceramics were prepared by cold isostatically pressed and sintered 1200°C with a dwell time of 1 hour. A human bone cell line MG-63 cells were used to test biocompatibility of AHA and THA ceramics. Cell suspensions in DMEM containing 10% FBS and 1% penicillin-streptomycin were seeded onto 24-well plate containing THA and AHA ceramics. Cell proliferation was evaluated by MTS assay, and cell morphology was observed by SEM.

The encapsulation and immobilization of biomolecules on solid materials, mesoporous SBA-15, have been studied. Highly ordered hexagonal mesoporous silicates (MPS) with different mean pore sizes have been synthesized using two kinds of triblock copolymers (P123 or L123) as a template. The mixture of tetraethyl orthosilicate (TEOS) and the triblock copolymer (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol)) was stirred and hydrothermally treated at various temperatures to form the MPS structure. Higher temperatures during stirring and hydtrothermal treatment led to the enlargement of pore size. UV-spectrometry was performed to determine the amount of bovine serum albumin (BSA) encapsulated in MPS. It was found that the adsorption processes of BSA on/in MPS could be well described by intraparticle diffusion model.

Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. As a result, neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective.

Amorphous calcium polyphosphate (CPP) has potential as an implantable drug delivery matrix by virtue of a low temperature gelling protocol that has been shown to eliminate burst release and extend drug release time from the matrix. However, a greater understanding of this material's interaction with aqueous environments is needed to more fully exploit this application. Variations in aqueous exposure were assessed using as-made amorphous CPP as well as CPP processed using established low temperature protocols. Solid-state ³¹P-NMR along with thermal and X-ray diffraction analyses were used to track resulting structural changes. Exposure to aqueous environments caused a reduction in CPP chain length that was dependant on gel time and mode of exposure. Significantly, increased gel times or water availability further resulted in crystallization events upon drying, except in the presence of a buffered solution. In general, drug elution studies showed an increase in the burst release of vancomycin from CPP disks gelled for extended periods, with matrix-water interactions appearing to be most influential during the drug loading stage. Overall, this study shows that CPP drug delivery matrices can be produced with tailored properties by closely controlling CPP-water interactions during processing.

In order to establish a reasonable biomimetic condition for compressive strength of bioactive ceramics, the compressive strengths of several commercial bioactive ceramics were measured under various conditions. All specimens except for one of Japanese ceramics, specimen A, showed no significant differences among the conditions, but showed a tendency of decreasing the compressive strength more than 10% in comparison to the dry condition that was conventionally described in product brochures. Further, the specimen A indicated a significant decrease of the compressive strength in 24h soaking conditions. Accordingly, a recommended biomimetic condition would be that specimen would be soaked in PBS after deaeration at 25°C for 24h and measured in air after brief wiping surface liquid.

Recently, the treatments of hepatocellular carcinoma with nano-hydroxyapatite (nano-HAP) particles have been given much attention. In this study, a new kind of nano-HAP particles was prepared by a homogenous method, and these particle diameters and their distribution, crystallization degree, chemical bondings, and morphology were characterized by laser scattering particle analyzer, X-ray diffraction, FTIR spectrum, transmission electron microscope, and electron diffraction. The results showed that the average particle diameter of nano-HAP was 59.9 nm, the prepared nano-HAP was amorphous and having a low crystallization degree. Furthermore, the characteristic absorption peaks of HAP appeared in FTIR spectra and the electron diffraction annuli was also clear. The prepared nano-HAP particles were used for the treatment of hepatocellular carcinoma. The inhibition effect was determined in vitro for three different concentrations by MTT methods. The results demonstrated that the prepared nano-HAP with a size of 59.9 nm most effectively inhibited the proliferation of hepatocellular carcinoma cells and the inhibition rate was more than 70%.

The purpose of this study was to obtain an appropriate geometry of porous hydroxyapatite scaffold for hard tissue formation in most of the pores. Porous cylindrical hydroxyapatite structures with a hollow center as a scaffold were manufactured. The diameter of a hollow center was 2 or 3 mm. Bone marrow cells were obtained from bone shafts of femora of 6-week-old male Fischer 344 rats. The cell/hydroxyapatite composite scaffolds were implanted in dorsal subcutis of 7-week-old male Fischer 344 rats. They were removed 8 weeks postoperatively. Serially sectioned paraffin specimens were made and observed histologically. The ratio of pores including hard tissue to the number of total pores per a square centimeter of the cross-sectional area in the scaffolds was calculated. In the scaffold with a hollow center measuring 2mm in diameter, a new hard tissue formation was observed near the superficies and the number of pores including hard tissue was 260.6 ± 60.8/cm². In the scaffold with a hollow center measuring 3mm in diameter, new hard tissue was observed between superficies and the wall of the hollow center. The number of pores including hard tissue was 589.6 ± 73.3/cm².

Phosphate coating layer was produced on titanium substrates by hydrothermal treatment with zinc phosphate solutions. Phosphatizing reaction produced zinc-titanium-phosphate coating layer on the surface by hydrothermal treatment at 250°C. Ti substrate treated with low concentration of zinc phosphate solution for 14 h was not fully covered by the coating layer. On the other hand, surface coverage on Ti substrate treated with a high concentration of zinc phosphate solution for only 6 h was enhanced completely. SEM and XPS results indicated that the formation of the coating layer was inhibited by surface oxide layer. The coating layer was strongly attached on Ti substrate, moreover, the bonding strength between the coating layer and the Ti substrate was higher than the mechanical strength of binder.

In this article, the mechanical characterization of a monolithic cup made of BIOLOX®delta with a porous ceramic coating for osseointegration is presented. During the coating process, a ceramic slurry is deposited on a green substrate, both slurry and substrate are based on BIOLOX®delta. To achieve a porous coating, organic pore-forming agents were used which are pyrolized in the following sintering process. Porosities of 18 to 47% could be reached depending on the layer thickness. Extensive mechanical investigations were applied on the fabricated cups to verify the suitability of the produced porous layers for biomechanical demands of the interface between bone and dense substrate. The test results showed that coated ceramic cups require comparable push out forces for the disconnection from artificial bone to established metal shells with plasma sprayed titanium coatings.

Profile accuracy of spherical α-TCP ceramics (artificial bone units) was improved by a precision fabrication method named "hydro-casting." Hydro-casting shapes α-TCP slurry into spherical shape by dispensing definite quantity of α-TCP slurry in an oil and fixing the slurry's shape by two-stage gellation. Resulting α-TCP spheres exhibit almost uniform shape and interunit gaps that would establish schematic features of porous body fabricated by "Mosaic-like ceramics fabrication (MLCF)."

Chitosan-γ-glycidoxypropyltrimethoxysilane (GPTMS)-tetraethoxysilane (TEOS) hybrid membranes were prepared by a sol-gel method. Effects of Si(IV) released from them on proliferation and differentiation were examined in terms of cell metabolic activity and alkaline phosphatase (ALP) activity of MG63 osteoblastic cells. The amount of Si(IV) released from the hybrid membranes increased with the TEOS content. Released Si(IV) inhibited cell proliferation, while it promoted cell differentiation. Thus, osteocompatibility of the chitosan hybrid membranes can be controlled due to the amount of Si(IV) released from them as the hybrids in the system chitosan-GPTMS-TEOS are applied for cell culture.

Due to osteoconductivity of hydroxyapatite (HA), HA/polymer composite scaffolds have been investigated for bone tissue engineering by various groups. In scaffold fabrication, electrospinning of ultrafine fibrous scaffolds incorporated with substantial amounts of evenly distributed HA nanoparticles is still a challenge. The problem of nanoparticle agglomeration not only reduces the electrospinning efficiency but also undermines the homogeneity of the distribution of the HA nanoparticles along the fibers. In this study, an approach using ultrasonification was developed so as to electrospin fibrous nanocomposite scaffolds having the carbonated HA (CHA) nanosphere content up to about 15 wt% with minimal agglomeration of CHA nanospheres. SEM and EDX results showed an even distribution of CHA nanospheres while FTIR results further confirmed the presence of CHA within the electrospun fibers. The nanocomposite fibrous scaffolds fabricated through this route could be used in further investigations for bone tissue engineering applications.

Difference in osteoclast responses (i.e., apoptosis, actin ring formation) to tricalcium phosphate (TCP) in culture medium supplemented with zinc and to zinc-containing tricalcium phosphate (ZnTCP) was investigated in this study. On the TCP ceramic, an increase in zinc ion in the culture medium within the range between 0.3 and 6.8 ppm significantly induced an increase in osteoclast apoptosis and a decrease in actin ring formation. However, even a high level of magnesium ion up to 100 ppm in the culture medium or up to 6.8 mol% in the ceramic was unlikely to influence osteoclast activity. There was almost no significant difference in osteoclast apoptosis and actin ring formation between ZnTCP with 1 mol% zinc and magnesium-containing tricalcium phosphate with 1.5 mol% magnesium ceramic which have the same solubility and the same dissolution rate. It is suggested that only an increase in zinc level outside resorption lacuna has an inhibitory effect on osteoclast resorption and that an increase in zinc level inside resorption lacuna could not influence osteoclast activity.

Template-assisted electrohydrodynamic atomisation (TAEA) spraying of nanometer-sized silicon-substituted hydroxyapatite (nanoSiHA) was used to pattern implant surfaces for guided cell growth to improve the repair and regeneration of medical implants. A suspension of nanoSiHA was prepared and characterized. Patterns of pillars and tracks of various dimensions were prepared using the suspension. It was found that the resolution of the pattern was affected by TAEA processing parameters, such as applied voltage, flow rate, distance between needle and substrate, and spray time. Fifteen minutes spraying time provided the most clear and uniform patterned topography with a distance between nozzle and substrate of 50mm and a flow rate of 4μl/min. Therefore, well-defined nanoSiHA patterns can be achieved by TAEA deposition, it thus offers great potential for patterning the surface of medical implants.

Metal nanoparticles play an important role in many different areas such as catalysis, electronics, sensors, and cancer therapy. Silver, in its many oxidation states (Ag⁰, Ag⁺, Ag²⁺, and Ag³⁺), has long been recognized as having an inhibitory effect towards many bacterial strains and microorganisms commonly present in medical and industrial processes. Silver was introduced in various materials including hydroxyapatite due to its biocompatibility. The unique size-dependent properties of nanomaterials make them superior and indispensable. In this work, nanohydroxyapatite/polyvinylpyrrolidone composite was doped with 2 different concentrations of silver nanoparticles prepared by reduction method. Several techniques like TEM, XRD, FT-IR, and SEM with EDS were used to characterize the prepared samples. The bioactivity test (soaking in SBF) at different short time intervals was characterized by using inductively coupled plasma-optical emission spectroscopy (ICP-OES) method. It is demonstrated that silver-doped nanohydroxyapatite obviously improves the bioactivity of the apatite at the early stages of immersion. The antibacterial inhibition over 3 types of bacteria (Staphylococcus aureus, Streptococcus mutans, and Pseudomonas) is under investigation.

Bioactive glasses with chemical composition 0.1 SiO2-0.2 CaO-0.2 Na2O-0.5 P2O5 have been prepared. The dielectric properties of the samples were measured in the frequency range from 100 Hz to 1 MHz and temperatures range from 100 to 370 K (Tg ≈ 400 K). The obtained data were analysed by the means of dielectric permittivity representation and modelled using the Havriliak–Negami equation. Various relaxation parameters were calculated with accuracy. Furthermore, investigation of the temperature dependence of their relaxation time using the Vogel– Tammam–Fulcher (VTF) model shows the weak interaction between alkali ions constituents and molecular networkformers for temperatures up to the glass transition.

Bioactive glasses with chemical composition 0.1 SiO2-0.2 CaO-0.2 Na2O-0.5 P2O5 have been prepared. The dielectric properties of the samples were measured in the frequency range from 100 Hz to 1 MHz and temperatures range from 100 to 370 K (Tg ≈ 400 K). The obtained data were analysed by the means of dielectric permittivity representation and modelled using the Havriliak–Negami equation. Various relaxation parameters were calculated with accuracy. Furthermore, investigation of the temperature dependence of their relaxation time using the Vogel– Tammam–Fulcher (VTF) model shows the weak interaction between alkali ions constituents and molecular networkformers for temperatures up to the glass transition.

The treatment of complicated crown-root fractures of tooth is often compromised by a fracture apical to the gingival margin and/or bone. This makes isolation difficult and compromises the adhesive union which is critical for a successful treatment. In the present case, the fracture line extended from cervical third of labial surface to cervical third of palatal surface sub gingivally which made the case a complicated crown root fracture. The reattachment of fragments would bring the vulnerable joint in the primary stress bearing area and in the subgingival region. Hence the tooth was removed traumatically with the help of periotome and intentional replantation was done which facilitated the attachment of fragments extra orally. Fragments reattachment was reinforced with the intraradicular fiber post and glass ionomer cement. Then the tooth was rotated 1800 to bring the subgingival fracture line to the labial surface where the occlusal load is less. As the amount of extra oral time is a critical factor in the success of reimplantation, the procedure was completed in 20 minutes. The teeth were stabilized with semi rigid splint for 6 weeks. Later full veneer crown was cemented on the tooth. The patient was followed up with clinical examination for mobility test, gingival sulcus depth and radiographic analysis to analyze the integrity of root, the alveolar cortex and the periodontal space for 12 months. The treatment is successful so far and has rendered satisfaction to both the clinician and patient.

The present research is an applied and documental review of the literature through meta-analysis. The statistical population was selected from the field of entrepreneurial performance in small and medium sized enterprises during 2003 to 2013 in which the internal/external effective factors for small/medium incorporates were quantitatively investigated. The findings of frequency distribution Table indicated that only (4) percent of the conducted studies focused on external factors while (96) percent of which were conducted in the internal factors domain. In addition, most of the studies were devoted to the two issues of human resources and research and development which were (26) percent. Moreover, there was no research related to the incorporate size and the status of consultative researchoriented unions and incorporates.

Myanmars mobile network is closing in on nearly 100% population coverage, and is striving for ever increasing geographical coverage. So much so that even future generations of water buffalo in remote areas will be tracked online as part of the “internet of things”, said Lars Erik Tellmann, CEO of Telenor Myanmar.

Recent developments from science and medical science show a growing interest in the anti-inflammatory activity of natural materials. Inflammation is the body’s physiologic response to injurious stimulation and is known to be mediated by various pro-inflammatory cytokines (e.g. TNF-α, IL-1β, IL-6 etc) and iNOS (inducible nitric oxide synthase). Quantum energy living body (QELBY) powder is a fusion of a special ceramic powder with natural clay mineral classified as quantum energy radiating material (QERM). The powder, composed mostly of silicon dioxide, is known to radiate reductive radiant energy. This study was designed to evaluate the anti-inflammatory activities of QELBY powder on RAW 264.7 mouse macrophage cells. QELBY powder was mixed with DMEM media and was allowed to stand for 48 hours. Afterwards, the supernatant was taken and diluted to various concentrations (0,5,10,20,40 μg/ml) prior to use. CCK-8 assay was done to determine the effects on cell viability. In addition, NO assay performed to elucidate the effect of QELBY on the NO production of LPS-stimulated macrophages. Lastly, RT-PCR and Western blot analysis for the detection of the mRNA and protein expressions, respectively, of proinflammatory cytokines and iNOS was made. Results demonstrated that QELBY powder causes both an increase in cell proliferation and a concentration-dependent decrease in NO production. Moreover, the mRNA and protein expressions of pro-inflammatory cytokines and iNOS were also inhibited. Taken together, these show that QELBY powder has anti-inflammatory activity and could therefore be used further in the development of materials that induce such kinds of benefits.

Recent developments from science and medical science show a growing interest in the anti-inflammatory activity of natural materials. Inflammation is the body’s physiologic response to injurious stimulation and is known to be mediated by various pro-inflammatory cytokines (e.g. TNF-α, IL-1β, IL-6 etc) and iNOS (inducible nitric oxide synthase). Quantum energy living body (QELBY) powder is a fusion of a special ceramic powder with natural clay mineral classified as quantum energy radiating material (QERM). The powder, composed mostly of silicon dioxide, is known to radiate reductive radiant energy. This study was designed to evaluate the anti-inflammatory activities of QELBY powder on RAW 264.7 mouse macrophage cells. QELBY powder was mixed with DMEM media and was allowed to stand for 48 hours. Afterwards, the supernatant was taken and diluted to various concentrations (0,5,10,20,40 μg/ml) prior to use. CCK-8 assay was done to determine the effects on cell viability. In addition, NO assay performed to elucidate the effect of QELBY on the NO production of LPS-stimulated macrophages. Lastly, RT-PCR and Western blot analysis for the detection of the mRNA and protein expressions, respectively, of proinflammatory cytokines and iNOS was made. Results demonstrated that QELBY powder causes both an increase in cell proliferation and a concentration-dependent decrease in NO production. Moreover, the mRNA and protein expressions of pro-inflammatory cytokines and iNOS were also inhibited. Taken together, these show that QELBY powder has anti-inflammatory activity and could therefore be used further in the development of materials that induce such kinds of benefits.

Binder-jet 3D printing responses of sea-shell powder based ceramic composites have been evaluated considering the material consolidation mechanisms and mechanical characterisations. Initial experimental printing trials are done manually, varying the composition of the composite powders from 5% to 50% of the seashell powder and the rest plaster. Overall, the seashell and plaster combinations worked well in terms of achieving the necessary green strengths within the binder-jet process conditions. Scanning electron microscopy and 3-point bending results indicated no significant loss of properties at lower levels of the seashell component, but the strength decreased beyond the 25% mark. The optimum levels of seashell powder are found to be within 15-20% by weight in terms of the best compression strengths. Neat sea-shell powder however goes too sticky immediately after the interaction with the binder liquid and does not show evidence of any binding mechanism that can be accelerated.

Tailor made bioceramic scaffolds in combination with the corresponding surface chemistry and biology is of great importance for a successful implantation and rapid osseo-integration. The present study investigates the fabrication of Hydroxyapatite (HA) scaffolds with defined macro porosity by means of powder based 3D-printing. In order to mime natural bone with its elastic collagen structure, the 3D-printed ceramic structures were post-treated by polymeric infiltration. Compressive Strength analysis (CS) confirmed the positive impact of an elastomeric phase on mechanical properties. 3D-printed HA scaffolds in combination with polymer result in biodegradable scaffolds with promising mechanical properties for potential use in regenerative medicine.

The aim of the present investigation was to evaluate the role of TiO2+ZrO2 in the system of 45S5 bioactive glass for improving the bioactivity as well as other physical and mechanical properties of 45S5 bioactive glass. The partial substitution of 1,2,3 and 4 mol% of mixed TiO2+ZrO2 (3:2) for SiO2 in 45S5 bioactive glass system was done by melting route at 1400°Cin a globar rod furnace in air. A comparative study on structural and mechanical properties, as well as bioactivity of the glasses, was reported. The glass properties were determined by XRD, FTIR spectrometry, SEM and the bioactivity of the glass samples were evaluated by in vitro test in simulated body fluid (SBF). Density and compressive strength of glass samples were measured. Results indicate that with the partial substitution of TiO2+ZrO2 for SiO2 in 45S5 bioactive glass system, the mechanical properties of the glasses were found to increase significantly. The glass samples exhibited higher density and compressive strength as compared to their corresponding 45S5 bioactive glass. The in vitro studies of glass samples in SBF had shown that the pH of the solution increased with increasing the time period for immersion during the initial stage of the reaction. This indicated the bioactivity of the samples had increased with increasing duration. On later stages, the decrease in pH of the solution with time had shown that the bioactivity of the samples had decreased.

Melt derived bioactive glasses and sol-gel derived glasses have been extensively investigated and are reported to be bioactive. Investigation of the bioactivity was conducted in different media, like conventional Simulated Body Fluid (c-SBF), Dulbecco's Modified Eagle's Medium (DMEM) and Tris buffer solution. The aim of this work is to investigate and evaluate the in vitro bioactivity assessment of two commonly used bioactive glasses-45S5 and 58S-soaked in DMEM and c-SBF, in order to compare the biological response of both glasses in organic and inorganic environ-ments. For the samples immersed in c-SBF, the onset of apatite formation on the surface of 45S5 grains was slightly delayed in comparison to 58S. After 3 days in DMEM 58S powders revealed the formation of a crystalline HCAp phase on the surface of all grains in contrary to 45S5, where a sparsely developed amorphous apatite phase was developed.

The aim of the present investigation was to evaluate the role of TiO2+ZrO2 in the system of 45S5 bioactive glass for improving the bioactivity as well as other physical and mechanical properties of 45S5 bioactive glass. The partial substitution of 1,2,3 and 4 mol% of mixed TiO2+ZrO2 (3:2) for SiO2 in 45S5 bioactive glass system was done by melting route at 1400°Cin a globar rod furnace in air. A comparative study on structural and mechanical properties, as well as bioactivity of the glasses, was reported. The glass properties were determined by XRD, FTIR spectrometry, SEM and the bioactivity of the glass samples were evaluated by in vitro test in simulated body fluid (SBF). Density and compressive strength of glass samples were measured. Results indicate that with the partial substitution of TiO2+ZrO2 for SiO2 in 45S5 bioactive glass system, the mechanical properties of the glasses were found to increase significantly. The glass samples exhibited higher density and compressive strength as compared to their corresponding 45S5 bioactive glass. The in vitro studies of glass samples in SBF had shown that the pH of the solution increased with increasing the time period for immersion during the initial stage of the reaction. This indicated the bioactivity of the samples had increased with increasing duration. On later stages, the decrease in pH of the solution with time had shown that the bioactivity of the samples had decreased.

Two types of polymer matrix composites were designed to use as bone replacement: PMMA+HA and PMMA+45S5® Blown Fibers. The materials were tested in vivo for 60 days and compared to two control groups: empty bone defect and porous PMMA. The histology results suggest that both materials provide a suitable scaffold for bone growth with the presence of newly formed bone tissue, blood vessels, osteocytes and osteoblasts cells. For a better understanding of the mechanical properties of scaffolds to bear physiological loads when implanted, compressive tests were carried out. The results showed difference in the compressive behaviour of the two composites, PMMA+HA specimens achieved higher values approaching 9.0 MPa of ultimate strength while PMMA+45S5® had values close to 8.0MPa. Both materials are suitable to bone replacement of small size areas.

The pro-angiogenic potential of copper ions could increase the viability of bone forming cells within a bone substitute scaffold, and so hasten healing, by stimulating infiltration of blood vessels into the scaffold. Copper-doped hydroxyapatite with x = 0, 0.5, 0.75 and 1 in the nominal formula Ca10(PO4)6CuxOyHz was prepared by solid state synthesis. Lattice parameters increased as x was increased, consistent with formation of Cu-O species on hydroxyl sites. In FT-IR spectra, the OH stretch (3572 cm-1) and the OH libration (631 cm-1) decreased in intensity as x was increased, and a band at 771-778 cm-1 was assignable to a Cu-O stretch, characteristic of Cu+ bands between 3140 and 3450 cm-1 related to copper-disturbed OH stretching vibrations. In UV visible spectra, bands between 400 and 800 nm were assignable to d-d transitions of Cu2+. Therefore we propose that Cu is present in these materials both as Cu+ and Cu2+.