Bioactive Ceramic Materials Research Articles

SYNTHESIS AND CHARACTERIZATION OF HYDROXYAPATITE-COLLAGEN-CHITOSAN (HA/Col/Chi) COMPOSITE BY USING EX-SITU WET PRECIPITATION METHOD

Hydroxyapatite (HA) was included mineral of apatite is a bioactive ceramic material and biocompatible, which has similarity with the nature of the bone chemical structure. The synthesis of hydroxyapatite (HA) by using wet precipitation method consists of calcination, hydration, HA synthesizes, and thermal treatment. The solution 0.3 M (NH4)2.HPO4 was dropped on the suspension of 0.5 M Ca(OH)2 from tutut (Bellamya javanica) shells. While collagen is extracted from the waste fish (Later calcarifer) scales by the following acid and alkali extraction methods. Synthesis of HA/Col/Chi composite by using ex-situ wet precipitation method that has been formed from 2 ml collagen of 2%, 2 ml chitosan of 2% mixed with 2 gram of HA powder was dissolved in 20 ml of an ethanol solution at room temperature. The spectrum of HA/Col/Chi composite by FTIR showed the presence of functional groups of HA, collagen, chitosan, and indicate the presence of molecular interactions between -OH, -COOH, -NH2 on collagen chains and -OH, -NH2 on chitosan, and there is an interaction between HA, amide I, and amide II in collagen. X-Ray Diffraction Analysis of HA/Col/Chi composite showed the single phase of HA. Analysis element components of HA showed that the Ca/P ratio obtained is 1.98. In the HA analysis by scanning electron microscopy showed the formation of HA in the presence of agglomeration and has an irregular shape. In addition, has a size of 2.76 - 6.48 µm. Keywords: Bellamya javanica, chitosan, collagen, ex-situ, hydroxyapatite, Lates calcarifer

Antibacterial activity of agricultural waste derived wollastonite doped with copper for bone tissue engineering

Bioactive ceramic materials with metal ions generation brought great attention in the class of biomaterials development and widely employed as a filler material for bone tissue regeneration. The present study aimed to fabricate calcium silicate based ceramic material doped with copper metal particles by sol–gel method. Rice straw of agricultural waste was utilized as a source material to synthesize wollastonite, then wollastonite was doped with copper to fabricate copper doped wollastonite (Cu–Ws) particles. The synthesized materials were subjected to physio-chemical characterization by TEM, DLS, FTIR, XRD and DSC analysis. It was found that the sizes of the WS particles was around 900nm, while adding copper the size was increased upto 1184nm and the addition of copper to the material sharpening the peak. The release of Cu ions was estimated by ICP analysis. The anti-bacterial potentiality of the particles suggested that better microbial growth inhibition against E. coli (Gram negative) and S. aureus (Gram positive) strains from ATCC, in which the growth inhibition was more significant against S. aureus. The biocompatibility in mouse Mesenchymal Stem cells (mMSC) showed the non-toxic effect up to 0.05mg/ml concentration while the increase in concentration was found to be toxic to the cells. So the particles may have better potential application with the challenging prevention of post implantation infection in the field of bone tissue engineering (BTE).

Optimization of Sintering Conditions for Improvement of Mechanical Property of a-Tricalcium Phosphate Blocks

Bioactive ceramic materials have been under research as bone substitute for several decades. To repair the high-load bearing bones, mainly cortical bones, there is a need for the substitute to possess comparable mechanical strength to cortical bone, of which the compressive strength ranges between 100 and 230 MPa. Two prevailing bone repairing material, β-tricalcium phosphate (β-TCP, β-Ca3(PO4)2) and hydroxyapatite (HAp: Ca10(PO4)6(OH)2) have been widely researched and sintered into dense blocks to meet the mechanical requirements. α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2), a high temperature polymorph of β-TCP, received relatively less attention and α-TCP dense sintered blocks have not been reported yet. In this research, we fabricated α-TCP dense blocks by sintering under various temperatures (1150-1400 °C) and the highest compressive strength was around 230 MPa.

Studies on Preparation and Characterization of 45S5 Bioactive Glass Doped with (TiO2 + ZrO2) as Bioactive Ceramic Material

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.

Studies on Preparation and Characterization of 45S5 Bioactive Glass Doped with (TiO2 + ZrO2) as Bioactive Ceramic Material

Studies on Preparation and Characterization of 45S5 Bioactive Glass Doped with (TiO2 + ZrO2) as Bioactive Ceramic Material

Various Parameters Affecting the Synthesis of the Hydroxyapatite Powders by the Wet Chemical Precipitation Technique

Hydroxyapatite (HA) is the most well-known mineral among the bioactive ceramic materials. HA crystals can be described as the calcium and phosphorus source that provides the sufficient density and strength of the bone as well as the bioactivity. Wet chemical precipitation technique has practical advantages such as simplicity of the experimental stages, low reaction temperatures, and the possibility of controlling the chemical composition and microstructure properties of the final product with harmless by-products. Therefore in this study, HA powders were synthesized by the wet chemical precipitation technique where calcium hydroxide (Ca(OH)2) was used as the calcium source precursor while orthophosphoric acid (H3PO4) as the phosphorus source precursor. There are several factors -such as the pH value of the reaction solution, dropping rate of the acid solution into the alkaline solution, temperature of the reaction solution, the stirring rate, etc.- that play role in the wet chemical precipitation process and some of these parameters were investigated in this work. Each of these factors individually may influence the crystal and/or amorphous phases that are obtained at the end of the process. Preparation and reaction of the precursor solutions, aging of the final solution and precipitation, filtrating and washing, drying and eventually heat treating the precipitation are the main steps that were carried out throughout the synthesis process. X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transform Infrared Spectroscopy (FTIR) characterization studies were applied in order to determine the chemical, microstructural and molecular bonding properties of the powders produced.

Structural characterization and in vitro bioactivity assessment of SiO2–CaO–P2O5–K2O–Al2O3 glass as bioactive ceramic material

The potassium based bioactive glasses have shown a better biocompatibility than soda containing bioactive glasses. Therefore, we have prepared a bioactive glass system containing potassium oxide and substituted with Al2O3 for further enhancement of bioactivity, physico-chemical properties, mechanical strength as well as its behavior to human osteosarcoma cells. The prepared bioactive glasses have a general formula, 42SiO2–34CaO-6P2O5–(18−x) K2O, where x=0, 0.5, 1, 1.5 and 2.5mol% of Al2O3. The in-vitro bioactivity of these samples was assessed by immersion in SBF solution for different time periods under physiological conditions. The formation of hydroxy carbonate apatite (HCA) layer on the surface of the glass samples after SBF treatment was confirmed by FTIR, XRD and SEM. The partial substitution of Al2O3 for K2O in glass demonstrated a significant increase in mechanical properties such as compressive strength and elastic modulus, respectively. The cytotoxicity, cell viability, proliferation, apoptosis and cell attachment were assessed using human osteosarcoma U2-OS cell lines. The cell culture studies demonstrated that the samples containing high concentration of Al2O3 showed a cytotoxic nature against cell lines. But the blood compatibility showed that all the samples were tolerant. Finally, this study clearly concludes that the optimization of Al2O3 in present potash based bioactive glasses would be potential biomaterials for biomedical applications.

Comparative evaluation of the biological properties of bone bioimplants Tutoplast® and bioactive ceramic material "Syntekost" when implanted in the middle ear in the experiment.

Comparative evaluation of the biological properties of bone bioimplants Tutoplast® and bioactive ceramic material "Syntekost" when implanted in the middle ear in the experiment.

Application of carbonaceous template for porous structure control of ceramic composites based on synthetic wollastonite obtained via Spark Plasma Sintering

The consolidation of highly porous nanostructured wollastonite powders was conducted via Spark Plasma Sintering (SPS) technique, and porous composite materials of high mechanical strength were obtained (Young׳s modulus over 60MPa). Peculiarities of structural parameters variation of studied materials under SPS conditions within the temperature interval 800–1000°С are described. The procedure of porous structure control of CaSiO3 composites, allows obtaining of hierarchically porous silica framework from nano- to microsized pores through a poreforming agent (carbonaceous template), is suggested. Obtained silicate composites are classified as bioactive ceramic materials, which are prospective for application in medical practice.

The physicochemical characterization and in vivo response of micro/nanoporous bioactive ceramic particulate bone graft materials

In this study, the physicochemical characteristics of calcium phosphate based bioactive ceramics of different compositions and blends presenting similar micro/nanoporosity and micrometer scale surface texture were characterized and evaluated in an in vivo model. Prior to the animal experiment, the porosity, surface area, particle size distribution, phase quantification, and dissolution of the materials tested were evaluated. The bone regenerative properties of the materials were evaluated using a rabbit calvaria model. After 2, 4, and 8weeks, the animals were sacrificed and all samples were subjected to histologic observation and histomorphometric analysis. The material characterization showed that all materials tested presented variation in particle size, porosity and composition with different degrees of HA/TCP/lower stoichiometry phase ratios. Histologically, the calvarial defects presented temporal bone filling suggesting that all material groups were biocompatible and osteoconductive. Among the different materials tested, there were significant differences found in the amount of bone formation as a function of time. At 8weeks, the micro/nanoporous material presenting ~55%TCP:45%HA composition ratio presented higher amounts of new bone regeneration relative to other blends and a decrease in the amount of soft tissue infiltration.

Processing of a multi‐layer polyetheretherketone composite for use in acetabular cup prosthesis

ABSTRACTThe hydroxyapatite polyetheretherketone (HAPEEK) as a non‐degradable bioactive polymer composite material with coating of hydroxyapatite (HA) as a bioactive ceramic material can enhance the osteointegration of carbon fiber reinforced polyetheretherketone (CFRPEEK) as a non‐degradable bioinert polymer composite. This study describes the joining process of CFRPEEK and HAPEEK beam components and coating process of HA on the HAPEEK substrate to achieve the multi‐layer PEEK composite for use in the application of acetabular cup prosthesis. The CFRPEEK and HAPEEK components were ultrasonically welded while the HA was plasma sprayed on the HAPEEK substrate. Ultrasonic welding parameters (length and direction of the energy directors at the interface, welding time, and pressure) were investigated by single cantilever beam and lap shear tests to achieve the optimum bonding strength of CFRPEEK and HAPEEK components. Plasma spraying parameters (e.g., surface speed, powder feed, current, primary gas flow, and system voltage) were altered to achieve the good adhesion of HA coating on the HAPEEK substrate, which was evaluated by scratch test. The results showed that the proposed multi‐layer composite was successfully processed by carrying out the ultrasonic welding and plasma spraying coating processes. The outcomes of this study could be used to develop a non‐metal acetabular cup prosthesis using the proposed multi‐layer composition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40915.

A new method of fabricating robust freeform 3D ceramic scaffolds for bone tissue regeneration

Fabrication of three-dimensional (3D) scaffolds with appropriate mechanical properties and desired architecture for promoting cell growth and new tissue formation is one of the most important efforts in tissue engineering field. Scaffolds fabricated from bioactive ceramic materials such as hydroxyapatite and tricalcium phosphate show promise because of their biological ability to support bone tissue regeneration. However, the use of ceramics as scaffold materials is limited because of their inherent brittleness and difficult processability. The aim of this study was to create robust ceramic scaffolds, which have a desired architecture. Such scaffolds were successfully fabricated by projection-based microstereolithography, and dilatometric analysis was conducted to study the sintering behavior of the ceramic materials. The mechanical properties of the scaffolds were improved by infiltrating them with a polycaprolactone solution. The toughness and compressive strength of these ceramic/polymer scaffolds were about twice those of ceramic scaffolds. Furthermore, the osteogenic gene expression on ceramic/polymer scaffolds was better than that on ceramic scaffolds. Through this study, we overcame the limitations of previous research on fabricating ceramic scaffolds and these new robust ceramic scaffolds may provide a much improved 3D substrate for bone tissue regeneration.

Porosity and solubility of bioactive calcium-phosphate glass ceramic materials for bone endoprosthesis replacement

Questions concerning the solubility of glass ceramic materials based on calcium-phosphate glass in water and solutions simulating the physiological medium of a living organism are examined. The relation between the level, character and size of pores in a material and its solubility is determined. Recommendations for using the new materials in medical practice are made.

Polydimethylsiloxane/Calcium Phosphates Composites: Effect of the Fillers Modification on the Cross-Linking and Surface Energy

A potential approach to achieving the objective of favorably modulating the biological response of implantable biopolymers combined with good mechanical properties is to consider compounding the biopolymer with a bioactive nanocrystalline ceramic biomimetic material with high surface area. In this work, n-HAp (nanohydroxyapatite) and n-α-TCP (nanoα-tricalcium phosphate) powders were modified by silane coupling agent and mixed with poly (dimethyl siloxane) gum so nanocomposites could be achieved. The influence of the introduction of modified and unmodified calcium phosphate particles on the composite thermodynamics parameters of cross-linking, static contact angle and surface energy were investigated. It was found that the dispersion state of modified particles in the silicone matrix was homogeneous. The introduction of fillers into the silicone matrix changed the enthalpy of cross-linking. The addition of unmodified particles led to higher surface energy values, on the other hand, modified particles led to lower surface energy values.

Polyhedral oligomeric silsesquioxane (POSS)–poly(ethylene glycol) (PEG) hybrids as injectable biomaterials

One of the major issues with the currently available injectable biomaterials for hard tissue replacement is the mismatch between their mechanical properties and those of the surrounding bone. Hybrid bone cements that combine the benefits of tough polymeric and bioactive ceramic materials could become a good alternative. In this work, polyhedral oligomeric silsesquioxane (POSS) was copolymerized with poly(ethylene glycol) (PEG) to form injectable in situ cross-linkable hybrid cements. The hybrids were characterized in terms of their mechanical, rheological, handling and in vitro bioactive properties. The results indicated that hybridization improves the mechanical and bioactive properties of POSS and PEG. The Young moduli of the hybrids were lower than those of commercial cements and more similar to those of cancellous bone. Furthermore, the strength of the hybrids was similar to that of commercial cements. Calcium deficient hydroxyapatite grew on the surface of the hybrids after 28 days in PBS, indicating bioactivity. The study showed that PEG–POSS-based hybrid materials are a promising alternative to commercial bone cements.

High surface area sol–gel nano silica as a novel drug carrier substrate for sustained drug release

Among various carrier materials for drug delivery, silica has been found to be significant for loading and sustained release of the drug. In the present study, the antibiotic gentamicin was incorporated in various amounts on to a silica matrix, using a sol–gel subcritical drying route. Crack free silica rods with a length of 1–1.5cm, diameter of 0.5cm and density of 1.35g/cm3 incorporated with gentamicin were obtained. The incorporation of gentamicin into the silica matrix was revealed by FTIR. The adsorption–desorption isotherms and pore size distribution were studied in detail. The drug elution patterns were analysed and show a biphasic mode of release. After the initial burst release, a constant release pattern is observed. A release value above the minimum inhibitory concentration (MIC) is always maintained. The amount of drug released is higher than that of many other bioactive ceramic materials. An attempt has been made to correlate the functional properties with the porosity features.

Mechanical characterization of injection-molded macro porous bioceramic bone scaffolds

Bioactive ceramic materials like tricalcium phosphate (TCP) have been emerging as viable material alternatives to the current therapies of bone scaffolding to target fracture healing and osteoporosis. Both material and architectural characteristics play a critical role in the osteoconductive capacity and strength of bone scaffolds. Thus, the objective of this research was to investigate the sintering temperature effect of a cost-effective manufacturing process on the architecture and mechanical properties of a controlled macro porous bioceramic bone scaffold. In this study the physical and mechanical properties of β-TCP bioceramic scaffolds were investigated as a function of the sintering temperature in the range of 950–1150 °C. Physical properties investigated included bulk dimensions, pore size, and strut thickness; and, compressive mechanical properties were evaluated in air at room temperature and in saline solution at body temperature. Statistically significant increases in apparent elastic modulus were measured for scaffolds sintered at higher temperatures. Structural stiffness for all the specimens was significantly reduced when tested at body temperature in saline solution. These findings support the development of clinically successful bioceramic scaffolds that may stimulate bone regeneration and scaffold integration while providing structural integrity.

Bioactive ceramic composite materials in hydroxyapatite-tricalcium phosphate system

Materials in hydroxyapatite-tricalcium phosphate systems are promising for the use in cell technologies for regeneration of damaged bone tissue. The results of investigations of the influence of the synthesis conditions on the phase composition of materials and the formation of their structure and properties upon baking of powders are given. The parameters of the process of preparation of materials with a desired ratio of phase components are determined, from hydroxyapatite to three-phase materials, containing tricalcium phosphate of α and β modifications. The features of the effect of partial substitution of magnesium for calcium on the phase formation in the studied system are established. The bases of the technology of composite ceramics are developed, including grains from synthesized substances, and investigations of their solubility and biocompatibility are performed.

Polycrystalline coating of hydroxyapatite on TiAl6V4 implant material grown at lower substrate temperatures by hydrothermal annealing after pulsed laser deposition

Hydroxyapatite (HA) is a bioactive ceramic material that mimics the mineral composition of natural bone. This material does not possess acceptable mechanical properties for use as a bulk biomaterial; however, it does demonstrate significant potential for use as a coating on metallic orthopaedic and dental prostheses. Pulsed laser deposition (PLD) of thin films of HA on TiAl6V4 have shown crystalline coatings to be obtained at temperatures of the order of 350-500 degrees C. This condition of high substrate temperature promoted the oxidation of the substrate surface prior to the growth of the HA layer and the oxidation layer degraded the adhesion of the coating to the substrate. In this study, thin films of HA were deposited on TiAl6V4 alloy at a lower temperature of 200 degrees C by PLD and crystallized by a hydrothermal treatment at 100 degrees C. The film was subjected to mechanical as well as cell viability tests in vitro. The thickness, roughness, crystallanity, composition ratio, adhesive strength, and cell adhesion of the film suggest the application of this technique for producing bioactive implants.

Superior in vitro biological response and mechanical properties of an implantable nanostructured biomaterial: Nanohydroxyapatite–silicone rubber composite

A potential approach to achieving the objective of favorably modulating the biological response of implantable biopolymers combined with good mechanical properties is to consider compounding the biopolymer with a bioactive nanocrystalline ceramic biomimetic material with high surface area. The processing of silicone rubber (SR)–nanohydroxyapatite (nHA) composite involved uniform dispersion of nHA via shear mixing and ultrasonication, followed by compounding at sub-ambient temperature, and high-pressure solidification when the final curing reaction occurs. The high-pressure solidification approach enabled the elastomer to retain the high elongation of SR even in the presence of the reinforcement material, nHA. The biological response of the nanostructured composite in terms of initial cell attachment, cell viability and proliferation was consistently greater on SR–5 wt.% nHA composite surface compared to pure SR. Furthermore, in the nanocomposite, cell spreading, morphology and density were distinctly different from that of pure SR. Pre-osteoblasts grown on SR–nHA were well spread, flat, large in size with a rough cell surface, and appeared as a group. In contrast, these features were less pronounced in SR (e.g. smooth cell surface, not well spread). Interestingly, an immunofluorescence study illustrated distinct fibronectin expression level, and stronger vinculin focal adhesion contacts associated with abundant actin stress fibers in pre-osteoblasts grown on the nanocomposite compared to SR, implying enhanced cell–substrate interaction. This finding was consistent with the total protein content and SDS–PAGE analysis. The study leads us to believe that further increase in nHA content in the SR matrix beyond 5 wt.% will encourage even greater cellular response. The integration of cellular and molecular biology with materials science and engineering described herein provides a direction for the development of a new generation of nanostructured materials.