Crystalline Calcium Phosphate Research Articles

Tendon Biomineralization

Due to understandable difficulties with obtaining research materials from humans, bio mineralogical studies were carried out on chicken and beef tendons. Those were chosen as material where biomineralization phenomena occur in a similar fashion as in human tendons. Tendons that were studied were both young and older, at various ages, located both near their connection with bone and with muscle. In the studies, binocular microscopy, polarizing microscopy, and scanning microscopy with EDS chemical analysis attachment were used. It was concluded that tendons undergo progressive mineralization with age. Its early stages are element –mostly calcium and phosphorus–substitutions into the biological structures of collagen that builds tendons. It develops in areas of tendon microinjuries. That mineralization can be discovered only using precise chemical methods because it’s virtually invisible under the microscope, even in great magnifications. In older tendons, especially in places where they connect with bone, but also in muscle areas, the highest level of tendon mineralization with weakly crystalline calcium phosphates of mineralogical properties of hydroxyapatite is observed.

Stabilisation of amorphous calcium phosphate in polyethylene glycol hydrogels

Acellular polymer-calcium phosphate composites are promising bone graft materials. Hydrogels are suitable for providing a temporary matrix, while calcium phosphate minerals serve as ion depots for calcium and phosphate required for de novo bone formation. Crystalline calcium phosphates are stable under biological conditions and are commonly used in such scaffolds. However, the low solubility of these phases reduces the availability of free ions and potentially obstructs the remodelling necessary for the formation of mineralised tissue. Here, we investigate two different strategies to stabilise amorphous calcium phosphates in a synthetic polyethylene glycol-based hydrogel matrix.In vitro experiments mimicking an injectable application showed that amorphous calcium phosphate (ACP) of variable stability was formed in the hydrogel matrices. In additive-free composites, ACP transformed into brushite within minutes. Citrate or zinc additives were found to stabilise the formed ACP phase to different degrees. In the presence of citrate, ACP was stable for at least 2 h before it transformed into hydroxyapatite within 3–20 days. Partial calcium substitution with zinc (Zn/Ca = 10%) produced zinc-doped ACP of high stability that did not show signs of crystallisation for at least 20 days.The presented methods and findings open new possibilities for the design of novel injectable synthetic bone graft materials. The possibility to produce ACP with tailorable stability promises great potential for creating temporary scaffolds with good osteogenic properties. Statement of significanceSynthetic hydrogel-calcium phosphate (CaP) composites are promising biomaterials to replace human- and animal-derived bone scaffolds. Most reported hydrogel-CaP composite materials employ crystalline CaP phases that lack the osteoinductive properties of autograft. Stabilising amorphous calcium phosphates (ACP) could overcome this limitation, readily delivering calcium and phosphate ions and facilitating remodelling into new bone tissue. The design of synthetic hydrogel-ACP scaffolds, however, requires more understanding of the mineralisation processes in such matrices. This study presents a model system to characterise the complex mineral formation and transformation processes within a hydrogel matrix. We demonstrate a facile route to produce self-mineralising injectable synthetic hydrogels and prove two different strategies to stabilise ACP for different periods within the formed composites.

Bioactivity behavior of Ag2O or CuO doped in glass systems of Na2O–CaF2–P2O5 and Na2O–CaO–P2O5 and their glass–ceramic derivatives assessed by FTIR, X-ray diffraction and SEM measurements

Glasses from the two systems (Na2O–CaF2–P2O5) and (Na2O–CaO–P2O5) doped with 0.2% CuO or Ag2O were prepared by melting annealing technique. Samples from the glasses were thermally heat treated to convert them to their glass–ceramic derivatives. FTIR spectra of the glasses and glass–ceramics were examined before and after immersion in SBF for 2 weeks at 37 °C to justify the spectral changes correlated with the bioactivity behavior of the tested samples. X-ray diffraction was utilized to identify the formed crystalline phases in the glass–ceramics upon thermal heat treatment. The crystalline phases are identified to be dependent on the chemical composition of the base glass and consisting of sodium phosphate and calcium phosphate crystalline phases beside combined sodium calcium fluoride phosphate crystalline phases and the sharing of the dopants. FTIR spectra after immersion indicate the appearance of two far-IR peaks which are characteristic for calcium phosphate or hydroxyapatite. SEM investigations confirm the bioactivity behavior through the appearance of the rounded or nodular-shaped crystalline phase. The optical and PL spectra indicate the complete transparency of the glasses in the visible except of interference of UV absorption band due to trace ferric ions impurities.

A "best fit" approach for synergistic surface parameters to guide the design of candidate implant surfaces.

Human bone resorption surfaces can provide a template for endosseous implant surface design. We characterized the topography of such sites using four synergistic parameters (fractal dimension, lacunarity, porosity, and surface roughness) and compared the generated values with those obtained from two groups of candidate titanium implant surfaces. For the first group (n = 5/group): grit-blasted acid etched (BAE), BAE with either discrete calcium phosphate crystal deposition or nanotube formation, machined titanium with nanotubes, or a nanofiber surface; each measured synergistic parameter was statistically compared with that of the resorbed bone surface and scored for inclusion in a "best fit" analysis. The analysis informed changes that could be made to a candidate implant surface to render it a closer "best fit" to that of the resorbed bone surface. In a second group of either titanium or titanium alloy implants their micro-topography, created by dual acid etching, was the same for each material substrate; but their nanotopographic complexity was changed by varying the degree of calcium phosphate crystalline deposits. These implants were also used in vivo where bone anchorage was tested using a tensile disruption test; and the "best fit" of synergistic parameters coincided with the best biological outcome for both titanium and titanium alloy implants. In conclusion, the four chosen synergistic parameters can be used to guide the sub-micron surface design of candidate implants, and our "best fit" approach is capable of identifying the surfaces with the best biological outcomes. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2165-2177, 2019.

MTA HP Repair stimulates in vitro an homogeneous calcium phosphate phase coating deposition.

BackgroundTo study the mineralization capacity in vitro of the bioceramic endodontic material MTA HP Repair.Material and MethodsBioactivity evaluation in vitro was carried out, by soaking processed cement disk in simulated body fluid (SBF) during 168 h. The cement surface was studied by Fourier transform infrared spectroscopy (FT-IR), field emission gun scanning electron microscopy (FEG-SEM) and energy dispersive X-ray analysis (EDX). Release to the SBF media of ionic degradation products was monitored using inductively coupled plasma atomic emission spectroscopy (ICP-AES).ResultsFT-IR showed increasing formation of phosphate phase bands at 1097, 960, 607 and 570 cm-1 with prolonged SBF soaking. FEG-SEM analysis reveals that HP produces a effectively surface covering consisting in homogeneous spherical phosphate phase aggregates with an average diameter of 0.5-1.0 µm. EDX analysis comparing un-treated (hydrated), 24 h and 72 h SBF treated surfaces of MTA HP Repair revealed phosphate deposition after 24 h, with high phosphorous/silicon element ratio signal measured after 24 h, indicating a very high phosphate phase deposition for this material.ConclusionsThe study shows that MTA HP Repair produces a quick and effective bioactive response in vitro in terms of crystalline calcium phosphate surface coating formation. The high bioactive response of MTA HP Repair makes it an interesting candidate for endodontic use as repair cement. Key words:Bioactive endodontic cements, bioactive response, MTA HP Repair.

Investigation of citric acid-assisted sol-gel synthesis coupled to the self-propagating combustion method for preparing bioactive glass with high structural homogeneity

In this research, the mechanism of an efficient strategy for the synthesis of 58S bioglass with high structural homogeneity by a citric acid assisted sol-gel route was investigated. This is an interesting approach to prepare bioactive glass via the sol-gel method with application potential in bone tissue engineering and also for the development of new biomedical devices. Herein, 58S bioglass was synthesized by two routes: conventional sol-gel method (CSG) and citric acid assisted sol-gel route coupled to the self-propagating combustion method (SPC). The effects of citric acid on the temperature required for 58S vitreous consolidation, long- and short-range ordering were investigated by several analysis techniques. Results suggested that citric acid molecules serve as an effective molecular template formed by molecular network raised from intermolecular forces, especially the hydrogen bonds, resulting from the chemical interactions between the COOH and hydroxyl groups (water, ethanol, POH, SiOH). In this scenario, citric acid controls the phase segregation during the drying and combustion steps of the gel in the SPC method by establishing chemical interactions (hydrogen bonds) with the superficial silanol groups present on the small-sized silica nanoparticles present in the sol governing their growth. Besides these mentioned features, the self-propagating combustion behavior exhibited by the nitrate-citrate in the SPC xerogel during the combustion step allowed the removal of the organic load and the consolidation of the vitreous structure at a temperature considerably lower than the sample obtained by the CSG method. Consequently, the SPC method leads to the formation of a glass structure with high homogeneity for the 58S, whereas the conventional sol-gel method produces a matrix enriched with calcium phosphate crystalline nuclei - glass-ceramic.

Effect of Crystalline Calcium Phosphate Coatings Prepared in an Aqueous Solution on Corrosion Resistance of Bioabsorbable Magnesium Alloy

Bioabsorbable magnesium (Mg) alloy was anodized in 1.0 M NaOH solution. Then the anodized Mg alloy was immersed in an aqueous solution with three times concentration of Ca2+and HPO42-in comparison with those of biological environment to improve its corrosion resistance. The whole surface of Mg alloy was successfully coated with crystalline calcium phosphate (CaP) within 1 day. The CaP coated Mg alloys showed high corrosion resistance in SBF.

Tailored disorder in calcite organization in tergite cuticle of the supralittoral isopod Tylos europaeus Arcangeli, 1938

The crustacean cuticle forms skeletal elements consisting of chitin-protein fibrils reinforced by amorphous and crystalline calcium carbonate and phosphate minerals. The edges of skeletal elements are of particular interest. They are subject to repeated strain and stress because they form transitions to the arthrodial membranes connecting them. These allow for relative movements of skeletal elements. In this study, we investigate structure, chemical composition, mineral organization and local mechanical properties of the anterior and posterior edges of the tergite cuticle in the conglobating beach isopod Tylos europaeus and compare these with the protective dorsal region of the tergites.The distribution of mineral phases at the edges resembles that of dorsal regions of the tergites. At the transition with the unmineralized arthrodial membrane the calcite containing distal exocuticle is replaced by epicuticular material and the subjacent cuticular layers containing amorphous calcium carbonate become enriched with amorphous calcium phosphate. At the edges, the local elastic modulus and hardness values are significantly lower compared to dorsal regions of the tergite cuticle, for both, the calcite and the amorphous mineral containing layers. The calcite within the tergite cuticle is assembled in different texture patterns: (i) almost random co-orientation, (ii) almost single crystalline calcite, and (iii) a graded organization. Calcite organization and co-orientation strength is highly variable, not only on very few tens of micrometres, but also between regions with different skeletal functionality. Our results show that besides structure and composition, patterns of calcite organization contribute to the hierarchical architecture and functionality of biological composites.

Corrosion resistance of glucose-induced hydrothermal calcium phosphate coating on pure magnesium

Glucose-induced composite coatings containing crystalline calcium phosphate and Mg(OH)2 interlayer were prepared on pure Mg substrate through hydrothermal deposition from alkaline solution. Surface composition, morphology and corrosion resistance of the coatings were characterized through XRD, FTIR, SEM, XPS, electrochemical and hydrogen evolution measurements. Results reveal that calcium phosphate coatings were composed of dicalcium phosphate anhydrous, calcium-deficient hydroxyapatite and hydroxyapatite. Corrosion resistance of pure Mg specimens was improved by the formation of such a calcium phosphate coating. The findings provide a novel strategy to design calcium phosphate conversion coatings with satisfactory corrosion resistance for biodegradable Mg implants.

Targeted Nanoparticle Binding to Hydroxyapatite in a High Serum Environment for Early Detection of Heart Disease

The impact of the protein-rich in vivo environment on targeted binding of functionalized nanoparticles has been an active field of research over the past several years. Current research aims at better understanding the nature of the protein corona and how it may be possible for targeted binding to occur even in the presence of serum. Much of the current research focuses on nanoparticles targeted to particular cell receptors or features with the aim of cellular uptake. However, similar research has not been performed on nanoparticles that are targeted to non-protein disease features, such as hydroxyapatite (HA). HA is a crystalline calcium-phosphate mineral that is present in large quantities in bone, and in smaller quantities in diseased cardiovascular tissue in cases of atherosclerosis or various stenoses. Our work aims to gain a better understanding of the behavior of PEGylated, peptide-coated superparamagnetic iron oxide nanoparticles (SPIONs) in a biologically-relevant high-protein environment (50% serum). We first determined that specific binding to HA occurs at significantly higher rates than non-specific binding in the absence of serum protein. We then examined nanoparticle interactions with serum proteins, including determination of the relative quantities of protein in the hard vs. soft protein corona. Finally, we examined specific and non-specific binding of targeted SPIONs in 50% serum, and determined that targeted binding may still occur with significant (p < 0.05) selectivity. We hypothesize that this may be because the nature of the binding interactions between the peptides and the HA are, by definition, less specific than the protein-protein interactions required for nanoparticles to bind to specific cells or cell features. These results suggest that these targeted SPIONs may be further developed for use in early detection of heart diseases such as atherosclerosis and aortic stenosis.

Amorphous Calcium Phosphate Formation and Aggregation Process Revealed by Light Scattering Techniques

Amorphous calcium phosphate (ACP) attracts attention as a precursor of crystalline calcium phosphates (CaPs) formation in vitro and in vivo as well as due to its excellent biological properties. Its formation can be considered to be an aggregation process. Although aggregation of ACP is of interest for both gaining a fundamental understanding of biominerals formation and in the synthesis of novel materials, it has still not been investigated in detail. In this work, the ACP aggregation was followed by two widely applied techniques suitable for following nanoparticles aggregation in general: dynamic light scattering (DLS) and laser diffraction (LD). In addition, the ACP formation was followed by potentiometric measurements and formed precipitates were characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The results showed that aggregation of ACP particles is a process which from the earliest stages simultaneously takes place at wide length scales, from nanometers to micrometers, leading to a highly polydisperse precipitation system, with polydispersity and vol. % of larger aggregates increasing with concentration. Obtained results provide insight into developing a way of regulating ACP and consequently CaP formation by controlling aggregation on the scale of interest.

Interaction of calcium, phosphorus and natural organic matter in electrochemical recovery of phosphate

To address the issues of eutrophication and the potential risk of phosphorus (P) shortage, it is essential to remove and recover P from P-containing streams to close this nutrient cycle. Electrochemical induced calcium phosphate (CaP) precipitation was shown to be an efficient method for P recovery. However, the influence of natural organic matter (NOM) is not known for this treatment. In this paper, the behavior of NOM and its effect on CaP precipitation was studied. In contrast to studies where NOM hindered CaP precipitation, results show that the interaction of NOM with CaP improves the removal of P, independent of the types of NOM. The P removal at the average increased from 43.8 ± 4.9% to 58.5 ± 1.2% in the presence of 1.0 mg L−1 NOM. Based on the yellow color of the CaP product, NOM is co-precipitated. The bulk solution pH with and without buffers has totally different effects on the precipitation process. Without buffer, CaP precipitates on the cathode surface in a wide pH range (pH 4.0–10.0). However, the precipitation process is completely inhibited when the bulk solution is buffered at pH 4.0 and 6.0. This is probably due to neutralization of OH− by the buffers. Regardless of the presence or absence of NOM and solution pH, the recovered products are mainly amorphous CaP unless the electrolysis time was increased to seven days with 4.0 A m−2, in which crystalline CaP formed. These findings advance our understanding on the interaction of Ca, P and NOM species for the application of electrochemical method for P recovery from real wastewater.

Twin-screw granulation: Understanding the mechanical properties from powder to tablets

Granulation is a technique commonly used before tabletting because it solves powder handling problems and ensures uniform filling of the compression dies. However, granulation can have an adverse impact on powder transformation into a tablet; i.e. tabletability.The aim of this work is to examine the effect of continuous wet granulation using twin-screw granulator (TSG) on the tabletability of the granulated materials. Also, the study investigates the mechanisms that dictate the change in tabletability after wet granulation using TSG.Granules and tablet properties were characterised using a range of mechanical and X-ray analysis techniques. It was found that wet granulation using TSG has an impact on the tabletability of the granulated pharmaceutical excipients. The presented work suggests that there is a correlation between the yield pressure, plastic and elastic work of the primary powder and the percentage of change in tabletability after granulation. The study found that plastically deformable materials like microcrystalline cellulose (MCC) experience a significant reduction of tabletability (up to 67%) when granulated compared with the direct compression of its powder. On the other hand, brittle materials like crystalline mannitol C160 or calcium phosphate dibasic anhydrous maintain their tabletability after twin-screw granulation.The presented results show that the granule size of microcrystalline cellulose and mannitol 100 SD does not affect tabletability for the range studied. However increasing the strength of granules was found to cause reduction of the tabletability. On the other hand, the granule size of mannitol C160 and calcium phosphate dibasic anhydrous did affect its tabletability.

Bioactivity Treatment for Co-Cr-Mo Alloy by Precipitation of Low Crystalline Calcium Phosphate Using Simulated Body Fluid with Alkalinized Condition

Bioactivity Treatment for Co-Cr-Mo Alloy by Precipitation of Low Crystalline Calcium Phosphate Using Simulated Body Fluid with Alkalinized Condition

Effects of current density, bicarbonate and humic acid on electrochemical induced calcium phosphate precipitation

Phosphorus (P) removal and recovery from sewage as calcium phosphate (CaP) by chemical precipitation is a widely used method. To avoid the addition of chemicals to increase the pH of the bulk solution and the need for a further separation step in conventional chemical precipitation process, we developed an electrochemical method, which can locally increase the pH near a Ti cathode. The separation of product and liquid then happens simultaneously by accumulating CaP at the electrode surface. The current density plays a crucial role in this system. A current density of 19 A/m2 results in the formation of crystalline CaP rather than amorphous CaP, but it does not enhance the removal of P in 24 h. Moreover, the current efficiency decreases with increasing current density. Furthermore, the increased H2 production at high current density may push the precipitated CaP back to the bulk solution, resulting in its dissolution. In the presence of bicarbonate (1–5 mM) or humic acid (1–20 mg/L), the removal of P was higher. This is probably due to the inhibited CaP precipitation in the bulk solution which in turn leaves more Ca and P ions available for the local precipitation on the cathode. However, bicarbonate at high concentration (10 mM) dropped P removal from 52 to 25%. This is caused by competition of carbonate and phosphate with the free Ca2+ ions and also by buffering the producted hydroxide ions at the cathode. The study shows that P can be removed as CaP by electrochemical precipitation at low current densities at common concentrations of bicarbonate and humic acid.

Trivalent chromium incorporated in a crystalline calcium phosphate matrix accelerates materials degradation and bone formation in vivo

Remodeling of calcium phosphate bone cements is a crucial prerequisite for their application in the treatment of large bone defects. In the present study trivalent chromium ions were incorporated into a brushite forming calcium phosphate cement in two concentrations (10 and 50 mmol/mol β-tricalcium phosphate) and implanted into a femoral defect in rats for 3 and 6 month, non-modified brushite was used as reference. Based on our previous in vitro findings indicating both an enhanced osteoclastic activity and cytocompatibility towards osteoprogenitor cells we hypothesized a higher in vivo remodeling rate of the Cr3+ doped cements compared to the reference. A significantly enhanced degradation of the modified cements was evidenced by micro computed tomography, X-ray and histological examinations. Furthermore the formation of new bone tissue after 6 month of implantation was significantly increased from 29% to 46% during remodeling of cements, doped with the higher Cr3+ amount. Time of flight secondary ion mass spectrometry (ToF-SIMS) of histological sections was applied to investigate the release of Cr3+ ions from the cement after implantation and to image their distribution in the implant region and the surrounding bone tissue. The relatively weak incorporation of chromium into the newly formed bone tissue is in agreement to the low chromium concentrations which were released from the cements in vitro. The faster degradation of the Cr3+ doped cements was also verified by ToF-SIMS. The positive effect of Cr3+ doping on both degradation and new bone formation is discussed as a synergistic effect of Cr3+ bioactivity on osteoclastic resorption on one hand and improvement of cytocompatibility and solubility by structural changes in the calcium phosphate matrix on the other hand. Statement of SignificanceWhile biologically active metal ions like strontium, magnesium and zinc are increasingly applied for the modification of ceramic bone graft materials, the present study is the first report on the incorporation of low doses of trivalent chromium ions into a calcium phosphate based biomaterial and testing of its performance in bone defect regeneration in vivo. Chromium(III)-doped calcium phosphate bone cements show improved cytocompatibility and both degradation rate and new bone formation in vivo are significantly increased compared to the reference cement. This important discovery might be the starting point for the application of trivalent chromium salts for the modification of bone graft materials to increase their remodelling rate.

Identification and quantification of plasma calciprotein particles with distinct physical properties in patients with chronic kidney disease

Calciprotein particles (CPP) are solid-phase calcium-phosphate bound to serum protein fetuin-A and dispersed as colloids in the blood. Recent clinical studies indicated that serum CPP levels were increased with decline of renal function and associated with inflammation and vascular calcification. However, CPP assays used in these studies measured only a part of CPP over a certain particle size and density. Here we show that such CPP are mostly artifacts generated during processing of serum samples in vitro. The native CPP in fresh plasma are smaller in size and lower in density than those artifactual CPP, composed of fetuin-A carrying amorphous and/or crystalline calcium-phosphate, and increased primarily with serum phosphate levels. We have identified several physicochemical factors that promote aggregation/dissolution of CPP and transition of the calcium-phosphate from the amorphous phase to the crystalline phase in vitro, including addition of anti-coagulants, composition of buffer for sample dilution, the number of freeze-thaw cycles, the speed for sample freezing, and how many hours the samples were left at what temperature. Therefore, it is of critical importance to standardize these factors during sample preparation in clinical studies on CPP and to investigate the biological activity of the native CPP.

Studies of Bone-Bonding Ability and Antibacterial Properties of Ag+, Cu2+ or Zn2+ ions Doping within Hench’s Bioglass and Glass-Ceramic Derivatives

Derived Hench’s bioglasses with specific ionic dopants Ag+, Cu2+, or Zn2+ have been prepared. The bone-boding ability or bioactivity behavior for the prepared glasses and their glass-ceramic derivatives has been investigated after immersion in phosphate solution for two weeks. Collective Fourier transform infrared absorption spectra (FTIR) and scanning electron microscopic (SEM) studies were conducted in order to study the in-vitro bioactivity behavior. X-ray diffraction (XRD) analysis was carried out to identify the crystallized phases upon thermal heat treatment through a two-step regime. The glasses and their glass-ceramic derivatives were tested to study their antibacterial or antifungal efficiency responding to the doped metal ions. FTIR spectra revealed the generation of two split peaks at about 560 and 605 cm−1, after immersion in (0.2 M) sodium phosphate solution (Na3PO4), signifying the formation of a crystalline calcium phosphate phase, leading to hydroxyapatite formation. SEM examinations show characteristic rounded or nodular microcrystals for hydroxyapatite which support the FTIR data. X-ray diffraction analysis indicated crystallization of the main soda-lime silicate phase (1Na2O.2CaO.3SiO2) besides a secondary silicon phosphate phase (SiO2.P2O5) in the studied glass ceramics. The route of crystallization is discussed on the basis of the presence of 6% P2O5; which facilitates the formation of phase separation and voluminous bulk crystallization of the main soda-lime silicate phase. The introduction of dopants is identified to cause no changes in the precipitated phases, with only minor changes in the percent of the crystalline phases. Experimental data indicate that the glass-ceramic samples are effective in bioactivity and antimicrobial efficiency.

Preliminary studies of PVA/PVP blends incorporated with HAp and β-TCP bone ceramic as template for hard tissue engineering.

Polyvinylalcohol (PVA) and Polyvinylpyrrolidone (PVP) blend incorporated with hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) is electrospun as nanofibrous composite scaffolds to act as suitable template for bone tissue engineering. Microscopic and spectroscopic characterizations confirm uniform integration of the crystalline calcium phosphate ceramics in the scaffolds. PVA-PVP blends are usually amorphous in nature and addition of phosphate ceramic particles specifically HAp elevates its crystalline behavior which is substantiated by XRD details. Further incorporation of ceramics is confirmed using FT-IR as characteristic PO43- groups for HAp and β-TCP were observed in the distinguished composites. Single glass transition temperature is observed for pure and composite blends indicating the formation of highly miscible blends. Also, addition of these ceramics augments the thermal stability of the blend scaffolds. Biocompatibility of the prepared (PVA: PVP)-HAp and (PVA: PVP)-TCP scaffolds is assessed using MG-63 Osteoblast cell lines in the time interval of 1st, 4th and 7th day. The cell viability percentage for (PVA: PVP)-HAp is high compared to β-TCP added blend composites, reinforcing the fact that scaffolds with good mechanical strength and enhanced porosity supports better cell adhesion.

Effect of Synthesis Temperature and Ca/P Ratios on Specific Surface Area of Amorphous Calcium Phosphate

Amorphous and low crystalline calcium phosphates are prospective candidates for bone implant manufacturing. Amorphous calcium phosphate (ACP) preparation technologies could be improved in terms of specific surface area (SSA) of obtained products. Current study is dedicated to the effect of synthesis temperature and Ca and P molar ratios (Ca/P) on SSA of ACP. Higher SSA can improve bioactivity of biomaterials. ACP was characterized by XRD, FT-IR, SEM and BET N2 adsorption techniques. Spherical nanoparticles (&lt;45 nm in size) were obtained independently of initial Ca/P ratio and synthesis temperature. For the first time comparison of SSA was shown for ACP obtained at different temperatures (0 °C and 20 °C) and Ca/P molar ratios (1.5, 1.67 and 2.2).