Tricalcium phosphate/hydroxyapatite (TCP/HA), hydroxyapatite (HA), chitosan and calcium sulphate (CaSO4) were studied and evaluated for possible bone tissue engineered construct acting as good support for osteogenic cells to proliferate, differentiate, and eventually spread and integrate into the scaffold. Surface morphology visualized by SEM showed that scaffold materials with additional fibrin had more cell densities attached than those without, depicting that the presence of fibrin and collagen fibers were truly a favourite choice of cells to attach. In comparison of various biomaterials used incorporated with fibrin, TCP/HA had the most cluster of cells attached.
A mixture with different compositions of HA and TCP were synthesize in this work by precipitation method using Ca(NO3)2 4H2 and (NH4)2HPO4 as the starting materials. A mixture with HA and TCP phases in different ratios were produced. The powders were sintered from 1000 degrees C to 1250 degrees C. The phase compositions of the mixtures were then studied via XRD. This work shows that the pH value determines the different phase compositions of the HA-TCP mixture. Chemical analyses were carried out by FTIR. The microstructure was observed under SEM.
Hydroxyapatite is a calcium phosphate bioceramic that has been shown by many authors to be biocompatible with bioactive properties. It is widely accepted as the best synthetic material available for surgical use as a bone graft substitute. HA granules produced by AMREC-SIRIM from local materials underwent 5 types of sterilisation techniques with different ageing periods. Samples were tested for chemical and phase composition and microbial contamination before and after being sterilised. From the microbiological tests done, none of the unsterilised positive control yielded a positive culture. Results from X-Ray diffraction studies found that all the sterilisation techniques did not chemically degrade or structurally change the HA granules significantly.
Hydroxyapatite (HA) has been increasingly used in biomedical applications due to its biocompatibility with living tissues. However, its use is limited to low load bearing areas due to the poor mechanical properties compared to bone. The aim of this project is to improve the mechanical properties of synthetic HA by optimising the processing method and also by using a phosphate based glass as a sintering aid to develop Glass Reinforced Hydroxyapatite (GR-HA). A phosphate based glass containing CaO, P2O5 and CaF2 was incorporated into HA at 2.5wt% and 5wt% additions during the milling process prior to sintering at 1300°C. The flexural strength mean values for GR-HA ranged from 80MPa to 110MPa. Pure HA exhibited a much lower flexural strength mean value ranging from 66MPa to 79MPa. The improved mechanical properties were associated with the occurrence of residual stress as a result of decomposition of HA to b-Tricalcium Phosphate (TCP) and in 5wt% GRHA to a-Tricalcium Phosphate (TCP).
Hydroxyapatite (HA) powder was synthesized via wet method using calcium nitrate hydrate (Ca(NO3)2.H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) as raw materials. Powder obtained was milled using various milling speed ranging from 250 to 400 r.p.m. and sintered at 1300°C for 2hrs. Due to the nature of HA powder that decomposed at high temperature, XRD technique have been used in this work to determine the phase composition of the HA powder and also the crystallite size. The unmilled sample was used as the control group. Results show that sufficient heat supply generated from the milling process, initiates the decomposition of HA phase into ȕ-tricalcium phosphate (ȕ-TCP). Decomposition of HA starts to occur at the milling speed of 300 rpm, i.e the formation of ȕ-TCP was occurred at lower sintering temperature. It was believed that the decomposition of HA was associated with the formation of an intermediate phase, oxyapatite. Moreover, the crystallinity and particle size of the produced powder is very much affected by the milling speed and the stability of the HA. All milled powders possess spherical shape particle.
Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering.
The incorporation of magnesium ions into the calcium phosphate structure is of great interest for the development of artificial bone implants. This paper investigates the preparation of magnesium-doped biphasic calcium phosphate (Mg-BCP) via sol gel method at various concentrations of added Mg. The effect of calcinations temperature (ranging from 500 degrees C to 900 degrees C) and concentrations of Mg incorporated into BCP has been studied by the aid of XRD, TGA and infrared spectroscopy (IR) in transmittance mode analysis. The study indicated that the powder was pure BCP and Mg-BCP with 100% purity and high crystallinity. The results also indicated that beta-tricalcium phosphate (beta-TCP) phase can be observed when the powder was calcined at 800 degrees C and above.
Tricalcium phosphate ceramic microcarrier has been developed and introduced to a new possibility for the culture of anchorage dependent animal cells of DF1. It was observed that the number of attached cells was increased with shorter time for both spinner vessel and stirred tank (ST) bioreactor. For those bioreactors, the total viable cell number that had been obtained is about 1.2 x 10(5) cell/ml.
Porous calcium phosphate ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Their high surface area leads to excellent osteoconductivity and resorbability providing fast bone ingrowths. Porous calcium phosphate can be produced by a variety of methods. This paper discusses briefly fundamental aspects of porous calcium phosphate for biomedical applications as well as various techniques used to prepare porous calcium phosphate.
This paper chronicled the development of a locally produced bone graft substitute based on calcium phosphate bioceramics called "GranuMaS--from concepts to clinics, and finally to its successful commercialization all within 5-year duration. It was a Prioritized Research (PR) collaborative project of 5 institutions namely SIRIM, ANM, USM, UKM and IIUM, funded by MOSTI to the amount of approximately RM2.5 millions under RM8. This paper also highlighted the requirements needed in terms of technical expertise/manpower, facilities and infrastructure, and government/institutional supports, as well as the challenge faced in developing and commercializing such product.
Ceramic materials play key role in several biomedical applications. One of them is bone graft which is use in treating bone defect which caused by injury or osteoporosis. Calcium phosphates based ceramic are preferred as bone grafts in hard tissue engineering because of their chemical compositions are similar to the composition of human bone, superior bioresorbable and bioactivity. In this study, β-tricalcium phosphate (β-TCP) ceramic was synthesized by using sol-gel method. Phosphorous pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as calcium and phosphate precursors. The effects of calcination temperature on the synthesis powder were studied using the XRD, SEM-EDS and FTIR techniques. It was found that calcination temperature greatly influence the purity of the synthesized powders. The β-TCP was the dominant phase with the formation of α-TCP at calcination temperature from 600 to 800°C. Pure β-TCP was obtained at calcination of 900°C. As the temperature increased to 1000°C, the β-TCP was decomposed to for calcium phosphate oxide (CPO). The sol-gel method has some advantages over other methods, mainly its simplicity and ability to produce pure β-TCP at lower calcination temperature.
Phase composition of calcium phosphate ceramic is a characteristic directly related to the biological response of implants due to the differences in mechanical and biochemical properties of these compounds. The biodegradation rate of biphasic calcium phosphate (BCP) can be controlled by altering the HA to β-TCP ratios. In this study the crystalline phase evolution of BCP synthesized via precipitation from aqueous solution of (NH4)2PO4 titrated into heated solution of Ca (NO3)2 was evaluated. The resulting powder was fabricated into porous scaffold using polyurethane foam method. Bulk powders were sintered from 700 - 1400°C to determine the most significant sintering temperature to obtain a stable and well crystallize BCP phases. The porous scaffolds were then sintered at selected temperature and the effects of various sintering times from 5,7,9,11,13 and 15 h were investigated. Bulk powders were characterized by dilatometer, IR analysis and XRD and porous scaffolds were analyzed by XRD and SEMEdx. RIR method was performed to show that the HA to β-TCP ratios were increased with increasing of sintering time and reached the maximum HA value at 11h. It is found that, the possibilities to manipulate the HA to β-TCP ratios in BCP porous scaffold by just controlling the sintering time of the scaffold without controlling the starting powder characteristics.
β-tricalcium phosphate (β-TCP) powders were synthesized by using various particles sizes (40 nm – 780 μm) calcium carbonate (CaCO3) and phosphoric acid (H3PO4) at room temperature (25 ˚C). The synthesized powders were characterized by using X-Ray Diffraction (XRD) method. The purity of β-TCP powders were determined from XRD pattern while the crystallite size of β-TCP powders were calculated by using Scherrer equation. Results shows that the purity of β-TCP powders were ranged from 20.33 % to 81.94 % while the crystallite size of β- TCP powders were ranged from 0.04391 μm to 0.06751 μm. From this work, particle size of CaCO3 will influenced the purity but not the mean crystallite size of synthesized β-TCP.
A process to produce calcium phosphate biomaterial was done using an organic based diethylhexyl phosphoric acid (DEHPA) as its starting material. The gel obtained from this reaction was used to study calcium phosphate transformation using in-situ XRD with temperature ranges from room temperature to 1300 o C. The results obtained from this analysis show the following phase transformation sequence gel > β-Ca2P2O7 > β-TCP + HA > α-TCP + HA. β-Ca2P2O7 was formed at 400 o C and the sample when heated up to 1000 o C, peaks of β- TCP and HA appeared showing the transformation of the β-Ca2P2O7 phase. When the sample was heated up further to 1200 o C, β-TCP transformed into α-TCP.
A major weakness of current orthopedic implant materials, for instance sintered hydroxyapatite (HA), is that they exist as a hardened form, requiring the surgeon to fit the surgical site around an implant to the desired shape. This can cause an increase in bone loss, trauma to the surrounding tissue, and longer surgical time. A convenient alternative to harden bone filling materials are injectable bone substitutes (IBS). In this article, recent progress in the development and application of calcium phosphate (CP)-based composites use as IBS is reviewed. CP materials have been used widely for bone replacement because of their similarity to the mineral component of bone. The main limitation of bulk CP materials is their brittle nature and poor mechanical properties. There is significant effort to reinforce or improve the mechanical properties and injectability of calcium phosphate cement (CPC) and this review resumes different alternatives presented in this specialized literature.
Introducing CO2 flux as the carbonate source had an effect on the carbonate content of carbonate apatite (CAp) synthesized by solid state reaction. The reactants were CaCO3 and beta-tricalcium phosphate (β-TCP) and the heat treatment in air was performed at 1250ºC followed by instant cooling in CO2 flux for temperatures ranging from 800ºC room temperature (RT) . The influence of CO2 flux at various temperature drop differences in the cooling process (1250ºC RT, 1250ºC–500ºC, 1250ºC–600ºC, 1250ºC–700ºC, and 1250ºC–800ºC) was tested to optimize the carbonation degree and subsequent effects on the physical and mechanical properties of CAp. Thermally treated samples revealed an increasing degree of carbonation, achieving a maximum of 5.2 wt% at the highest (1250ºC RT) and a minimum of 2.7 wt% at the lowest (1250ºC–800ºC) temperature drop differences, respectively. This showed that the carbonate content was correlated with the increase in exposure to CO2 flux. However, consistent compressive strength, tensile strength, density and porosity were observed against increasing temperature drop differences which indicated that the degree of carbonation exerted no influence on the physical and mechanical properties of CAp. This method enabled the synthesis of solid state CAp simply by exposing calcium phosphate mixtures to CO2 flux. It also allowed the control of carbonate content for desired medical applications.
This paper presents the development of novel alternative injectable calcium phosphate cement (CPC) composites for orthopaedic applications. The new CPC composites comprise β-tri-calcium phosphate (β-TCP) and di-calcium phosphate anhydrous (DCPA) mixed with bovine serum albumin (BSA) and incorporated with multi-walled carbon nanotubes (MWCNTs) or functionalized MWCNTs (MWCNTs-OH and MWCNTs-COOH). Scanning electron microscopy (SEM), compressive strength tests, injectability tests, Fourier transform infrared spectroscopy and X-ray diffraction were used to evaluate the properties of the final products. Compressive strength tests and SEM observations demonstrated particularly that the concomitant admixture of BSA and MWCNT improved the mechanical properties, resulting in stronger CPC composites. The presence of MWCNTs and BSA influenced the morphology of the hydroxyapatite (HA) crystals in the CPC matrix. BSA was found to act as a promoter of HA growth when bounded to the surface of CPC grains. MWCNT-OH-containing composites exhibited the highest compressive strengths (16.3 MPa), being in the range of values for trabecular bone (2-12 MPa).
Various materials have been used as scaffolds to suit different demands in tissue engineering. One of the most important criteria is that the scaffold must be biocompatible. This study was carried out to investigate the potential of HA or TCP/HA scaffold seeded with osteogenic induced sheep marrow cells (SMCs) for bone tissue engineering.
Widespread deforestation has resulted in soil degradation that is often linked to environmental and ecological changes. Rehabilitation of degraded forest is essential to prevent further degradation of the soil. Abundance of soil microbiota could serve as an essential biological indicator of soil health for rehabilitation success. An investigation was conducted to study the relationship between cellulolytic, nitrogen-fixing and phosphate-solubilizing microbial counts and age of rehabilitated forest. A random sampling design was used to obtain four replicates of five composite soil of 0–10 cm depth soil samples of 4, 9, 14 and 19-year-old rehabilitated forest. Three selective media: Congo red cellulose, nitrogen-free malate and calcium phosphate media were used for the enumerations of cellulolytic, nitrogen-fixing and phosphate-solubilizing microbes, respectively. Cellulolytic and phosphate-solubilizing microbes were counted based on the formation of clearing zones, while nitrogen-fixing microbes were based on the formation of blue halo on the respective media. There was positive linear relationship between age of the rehabilitated forest and microbial count. These findings revealed that the potentials of cellulolytic, nitrogen-fixing and phosphate-solubilizing microbial populations could be used as biological indicators of forest soil rehabilitation.