Addition Of HAp Research Articles

Effect of acidic nano ZSM‐5 modified by hydroxyapatite nanowires on flame‐retardant performance in PLA/IFR composite

AbstractFlame‐retardant polylactic acid (PLA) composites play critical role in construction fields. However, it is urgent to develop flame‐retardant PLA composites since PLA inherent flammability and melt dripping. Herein, we utilize intumescent flame retardant (IFR) with hydroxyapatite nanowires/acidic nano ZSM‐5 (HAP/HN) as synergist to improve the PLA flame‐retardant performance. According to scanning electron microscopy (SEM) observation, HN particles were distributed around with HAP and x‐ray diffraction, Fourier transform infrared spectrum show that the HAP/HN particles were successfully developed with the interaction of hydrogen bonds. The flame‐retardant results of PLA composites showed that the limited oxygen index value increased from 18.0% of neat PLA to 38.2% for HAP/HN sample, moreover the peak heat release rate (pHRR) was lower (~65%) than that of neat PLA (553 kW/m2). In addition, the char yield of PLA/IFR/HAP/HN sample increased from 9.5% to 54.2% for PLA/IFR/HN. SEM results showed that the char surface was smoother and denser with incorporation of HAP/HN. TG‐IR test also demonstrated that the intensity of CO was decreased obviously in gas phase due to the addition of HAP.

Fabrication and properties of hydroxyapatite/chitosan composite scaffolds loaded with periostin for bone regeneration

This paper reports a facile fabrication method of hydroxyapatite/chitosan (HAp/CS) composite scaffold with 3D porous structure without using any chemical cross-linkers. The HAp particles had an urchin-like hollow microstructure and high surface area, which was uniformly dispersed into the pore walls of the HAp/CS scaffold. The addition of HAp can efficiently enhance the mechanical properties and bioactivity of the HAp/CS scaffold. Moreover, periostin was successfully loaded onto the HAp/CS scaffold. When applied to the repair of bone defect in a rat mandibular model, the HAp/CS scaffold loaded with periostin can enhance osteointegration and accelerate bone regeneration. Our research combines periostin with the HAp/CS composite material, which provides a novel strategy to improve bone regeneration and has great application prospect in bone repair fields.

Porcelain Ceramic Tile Manufactured with the Addition of Hydroxyapatite in Ceramic Formulations

In this study, we developed formulations of a clay, kaolin, quartz, talc, and feldspar ceramic coating as a standard formulation, with the addition of Hap to improve the mechanical characteristics of the final product. The addition of Hap will help to fill the gaps in the formulation. Furthermore, it could lower the sintering temperature due to the high presence of calcium oxide in its composition. The main mineralogical phases (mullite, quartz, and anorthite) were identified in the sintered samples by X-ray diffraction. After evaluating the physical–mechanical properties (water absorption, linear shrinkage, apparent porosity, and resistance to flexion), the incorporation of Hap (5% in weight, 10% in weight, and 20% in weight) significantly altered the physical and mechanical properties of the final product, where we obtained, in relation to the standard formulation, an increase of more than 15% in mechanical resistance.

Fibrous PVA Matrix Containing Strontium-Substituted Hydroxyapatite Nanoparticles from Golden Apple Snail (Pomacea canaliculata L.) Shells for Bone Tissue Engineering.

A scaffold that replicates the physicochemical composition of bone at the nanoscale level is a promising replacement for conventional bone grafts such as autograft, allograft, or xenograft. However, its creation is still a major challenge in bone tissue engineering. The fabrication of a fibrous PVA-HA/Sr matrix made of strontium (Sr)-substituted hydroxyapatite from the shell of Pomecea canaliculate L. (golden apple snail) is reported in this work. Since the fabrication of HAp from biogenic resources such as the shell of golden apple snail (GASs) should be conducted at very high temperature and results in high crystalline HAp, Sr substitution to Ca was applied to reduce crystallinity during HAp synthesis. The resulted HAp and HA/Sr nanoparticles were then combined with PVA to create fibrous PVA-HAp or PVA-HA/Sr matrices in 2 or 4 mol % Sr ions substitution by electrospinning. The nanofiber diameter increased gradually by the addition of HAp, HA/Sr 2 mol %, and HA/Sr 4 mol %, respectively, into PVA. The percentage of the swelling ratio increased and reached the maximum value in PVA-HA/Sr-4 mol %, as well as in its protein adsorption. Furthermore, the matrices with HAp or HA/Sr incorporation exhibited good bioactivity, increased cell viability and proliferation. Therefore, the fibrous matrices generated in this study are considered potential candidates for bone tissue engineering scaffolds. Further in vivo studies become an urgency to valorize these results into real clinical application.

Regenerative Engineering of a Biphasic Patient-Fitted Temporomandibular Joint Condylar Prosthesis.

Regenerative medicine approaches to restore the mandibular condyle of the temporomandibular joint (TMJ) may fill an unmet patient need. In this study, a method to implant an acellular regenerative TMJ prosthesis was developed for orthotopic implantation in a pilot goat study. The scaffold incorporated a porous, polycaprolactone-hydroxyapatite (PCL-HAp, 20wt% HAp) 3D printed condyle with a cartilage-matrix-containing hydrogel. A series of material characterizations was used to determine the structure, fluid transport, and mechanical properties of 3D printed PCL-HAp. To promote marrow uptake for cell seeding, a scaffold pore size of 152 ± 68 μm resulted in a whole blood transport initial velocity of 3.7 ± 1.2 mm·s-1 transported to the full 1 cm height. The Young's modulus of PCL was increased by 67% with the addition of HAp, resulting in a stiffness of 269 ± 20 MPa for etched PCL-HAp. In addition, the bending modulus increased by 2.06-fold with the addition of HAp to 470 MPa for PCL-HAp. The prosthesis design with an integrated hydrogel was compared with unoperated contralateral control and no-hydrogel group in a goat model for 6 months. A guide was used to make the condylectomy cut, and the TMJ disc was preserved. MicroCT assessment of bone suggested variable tissue responses with some regions of bone growth and loss, although more loss may have been exhibited by the hydrogel group than the no-hydrogel group. A benchtop load transmission test suggested that the prosthesis was not shielding load to the underlying bone. Although variable, signs of neocartilage formation were exhibited by Alcian blue and collagen II staining on the anterior, functional surface of the condyle. Overall, this study demonstrated signs of functional TMJ restoration with an acellular prosthesis. There were apparent limitations to continuous, reproducible bone formation, and stratified zonal cartilage regeneration. Future work may refine the prosthesis design for a regenerative TMJ prosthesis amenable to clinical translation.

Hydroxyapatite Effect on the Corrosion Rate of AMC Al-Zn by Powder Metallurgy

Al-Zn-based AMC is a light metal, with low density, excellent mechanical and mechanical properties, suitable for use in automotive, electrical, general-purpose electronics, machinery and equipment. However, the development of this alloy is limited by its low hardness and low corrosion resistance, which limits its use in many applications. This corrosion process can cause fitting corrosion and can damage the passive oxide layer that protects the metal from corrosion. This study aimed to increase the corrosion resistance of AMC Al-Zn by adding hydroxyapatite ceramic reinforcement from snail shells in a corrosive medium of 3.5% NaCl solution. The HAp is used as an AMC amplifier. AMC uses Al-Zn alloys with a ratio of 90% to 10% by mass. The variation of HAp enhancer used was 10, 15, 20, 30 and 40% by weight. This AMC was produced by powder metallurgy using 250 KPa compression for 20 min with sintering at 550°C for 2 h followed by slow cooling. The characterization of Al-Zn-based AMCs was performed by electrodynamic polarization testing in 3.5% NaCl solution. From the experimental results, the addition of HAp snail waste at a concentration of 20% by weight with matrix composition Al90-Zn10 is an AMC preparation with optimal corrosion resistance. The corrosion rate of Al90-Zn10/20HAp is 0.01 mmpy, while the corrosion rate of Al90-Zn10/0HAp is 1.15 mmpy. The addition of HAp up to 20% by weight showed the highest micro-hardness (117.90 Hv) while the smallest micro-hardness occurred at AMC Al90-Zn10/0HAp (87.57 Hv). The HAp material could very well be used as an AMC-reinforced biomaterial for biomedical applications.

Effects of different calcium salts on the physicochemical properties of sliver carp myosin

To investigate the effects of different calcium salts on the physicochemical properties of myosin, the intermolecular interactions, particle size, surface hydrophobicity, reactive sulfhydryl group content and rheological properties of sliver carp myosin with the addition of four different kinds of calcium salts (CaCl2, calcium citrate (CC), nano-hydroxyapatite (HAP), tricalcium phosphate (TCP)) during gel processing were measured. The results showed that the addition of CaCl2 promoted the unwinding of α-helix, the increase in hydrophobic interactions, the formation of disulfide bonds of myosin, and increased the viscoelasticity of myosin. While, the addition of calcium citrate (CC) enhanced the hydrophobic interaction between myosin molecules, and the viscoelasticity of CC-added myosin was second only to the CaCl2-added myosin. On the contrary, the addition of HAP and TCP interfered with the hydrophobic interaction between myosin molecules, and greatly reduced the viscoelasticity of myosin. In summary, calcium with high calcium release rate can improve the physicochemical properties of myosin, HAP and TCP with a very low calcium release rate interfered with the formation of myosin gelation. And it could be concluded that the calcium ions played a leading role in the physicochemical properties of myosin, the more calcium ion that the calcium salt can release, the better physicochemical properties the myosin were. Our work may provide an insight into the phenomenon why different kinds of calcium salts differ from each other on affecting the physicochemical properties of myosin during gel processing.

N-Acetyl-Cysteine-Loaded Biomimetic Nanofibrous Scaffold for Osteogenesis of Induced-Pluripotent-Stem-Cell-Derived Mesenchymal Stem Cells and Bone Regeneration

To regenerate bone tissues, we investigated the osteogenic differentiation of induced-pluripotent-stem-cell-derived mesenchymal stem cells (iPSC-MSCs) and bone regeneration capacities using N-acetyl cysteine (NAC)-loaded biomimetic nanofibers of hydroxyapatite/silk fibroin (HAp/SF). The addition of HAp and NAC decreased the diameters of the electrospun fibers and enhanced the mechanical properties of the silk scaffold. The release kinetic curve indicated that NAC was released from NAC/HAp/SF nanofibers in a biphasic pattern, with an initial burst release stage and a later sustained release stage. This pattern of release of NAC encapsulated on the NAC/HAp/SF scaffolds prolonged the release of high concentrations of NAC, thereby largely affecting the osteogenic differentiation of iPSC-MSCs and bone regeneration. Thus, a new silk electrospun scaffold was developed. HAp was used as a separate nanocarrier for recharging the NAC concentration, which demonstrated the promising potential for the use of NAC/HAp/SF for bone tissue engineering.

FTIR spectroscopy characterization and critical comparison of poly(vinyl)alcohol and natural hydroxyapatite derived from fish bone composite for bone-scaffold

This paper presents the interaction comparison of poly(vinyl) alcohol (PVA) with hydroxyapatite derived from Spanish Mackerel (SM) and Whitefin Wolf Herring (WWH) bones, in different processing method. PVA filament and solution casting method illustrated higher crystallinity in the FTIR graph as compared to the PVA pellet and filament extrusion method. Besides, minimal interactions between PVA with glycerol and HAp was observed as well. PVA pellet and solution casting method portrait higher interaction as compared to the PVA filament and extrusion method. As for the HAp of SM and WWH, WWH had higher crystallinity and better cell adhesion with a higher Ca/P ratio while SM had relatively better mechanical strength with Ca/P ratio near to stoichiometric value. The loading of HAp (0, 2.5, 5, 10, 20, 30%) does not affect interactions of PVA/HAp composite in FTIR, and thermal properties in TGA. However, it caused an increase in crystallinity at low HAp loading and decreased at higher loading of HAp above 10%. Upon addition of HAp, tensile strength increased and elongation at break decreased. As the loading of HAp increased, both mechanical properties decreased. Scaffold with WWH composite possessed lower tensile strength and higher elongation at break than SM composite. The result of mechanical properties corresponded to the SEM result. ANOVA analysis justified the effect of HAp variations and loading on the mechanical properties of the composite was prominent.

PGS/HAp Microporous Composite Scaffold Obtained in the TIPS-TCL-SL Method: An Innovation for Bone Tissue Engineering.

In this research, we synthesize and characterize poly(glycerol sebacate) pre-polymer (pPGS) (1H NMR, FTiR, GPC, and TGA). Nano-hydroxyapatite (HAp) is synthesized using the wet precipitation method. Next, the materials are used to prepare a PGS-based composite with a 25 wt.% addition of HAp. Microporous composites are formed by means of thermally induced phase separation (TIPS) followed by thermal cross-linking (TCL) and salt leaching (SL). The manufactured microporous materials (PGS and PGS/HAp) are then subjected to imaging by means of SEM and µCT for the porous structure characterization. DSC, TGA, and water contact angle measurements are used for further evaluation of the materials. To assess the cytocompatibility and biological potential of PGS-based composites, preosteoblasts and differentiated hFOB 1.19 osteoblasts are employed as in vitro models. Apart from the cytocompatibility, the scaffolds supported cell adhesion and were readily populated by the hFOB1.19 preosteoblasts. HAp-facilitated scaffolds displayed osteoconductive properties, supporting the terminal differentiation of osteoblasts as indicated by the production of alkaline phosphatase, osteocalcin and osteopontin. Notably, the PGS/HAp scaffolds induced the production of significant amounts of osteoclastogenic cytokines: IL-1β, IL-6 and TNF-α, which induced scaffold remodeling and promoted the reconstruction of bone tissue. Initial biocompatibility tests showed no signs of adverse effects of PGS-based scaffolds toward adult BALB/c mice.

Photocatalytic activity of TiO2-P25@n-TiO2@HAP composite films for air depollution.

We report on an elaboration of new composite photocatalysts (TiO2-P25@ n-TiO2@HAP) based on grafted size-selected 5-nm titanium-oxo-alkoxo nanoparticles on P25-TiO2 nanoparticles and HAP obtained by co-precipitation of salts. The 5-nm oxo-TiO2 particles were prepared in a sol-gel reactor with rapid reagents micromixing. The photocatalytic test of ethylene degradation, in a continuous-flow fixed-bed reactor, showed an increase of the photocatalytic yield for the composite photocatalysts with an addition of HAP. This result was interpreted by a synergy between adsorption and photo-oxidation.

Mechanical Properties and Corrosion Resistance of Magnesium–Hydroxyapatite Composites Fabricated by Spark Plasma Sintering

Recent studies indicate that biodegradable magnesium alloys and composites are attracting a great deal of attention in orthopedic applications. In this study, magnesium–hydroxyapatite (Mg–HAP) composites with different compositions and grain size were fabricated by a spark plasma sintering (SPS) method. Their mechanical properties and corrosion behavior in a pseudo-physiological environment were investigated by pH measurements and inductivity coupled plasma (ICP) elemental analysis after an immersion test using Hanks’ solution. The results clearly showed that the addition of HAP improved both the mechanical properties and corrosion resistance. The results also indicated that the finer grain size improved most of the properties that are needed in a material for an orthopedic implant. Furthermore, the authors reveal that there is a strong correlation between the compressive strength and the porosity. In order to achieve the same compressive strength as human bone using these fabrication conditions, it is revealed that the porosity should be lower than 1.9%.

Strength and Bioactivity of Hydroxyapatite/White Portland Cement (HAp/WPC) under Simulated Body Fluid (SBF) Solution

In this study, the effects of curing white Portland cement (WPC) and hydroxyapatite mixed with white Portland cement (HAp/WPC) pastes in water and the in vitro biological environment on the compressive strength and bone-like apatite formation were examined. The compressive strength of both WPC and HAp/WPC pastes increased with longer curing periods in water. The compressive strength of WPC and HAp/WPC pastes was 51.88 and 25.67 MPa, respectively, after curing in water for 28 days. The compressive strength of both samples continuously increased during in vitro testing in a simulated body fluid (SBF). After 4 weeks of immersion in a SBF, the strengths of cured WPC and HAp/WPC samples were 59.01 and 28.06 MPa, respectively. It is due to continued hydration of WPC. The addition of HAp to WPC decreased the compressive strength of the sample. Alternatively, it enhanced bone-like apatite formation on the surface of the samples.

Mechanical and corrosion properties of Mg-Zn/HAP/Al2O3 hybrid composite

The effect of HAP and Al2O3 composition with constant of ceramic content of 15 wt. % on mechanical properties, microstructure, and corrosion behavior of degradable Mg-Zn/HAP/Al2O3 hybrid composite developed by powder metallurgy method were investigated. The microstructure was analyzed using an optical microscope and scanning electronic microscope while mechanical properties were evaluated for density and compression strength. Meanwhile, corrosion behavior in Hank Balanced salt solution (HBSS) was studied for 4 h. The addition of HAP and Al2O3 particles has improved the mechanical properties and corrosion properties of Mg-Zn alloy. The results show that 15 wt. % Al2O3 (without HAP) shows the higher density, hardness, and compression. However, the composite consisted of 10 wt. % HAP with 5 wt. % Al2O3 shows the lower corrosion rate.

Surface modification of 316L SS with HAp nano-particles using PMEDM for enhanced Biocompatibility

Abstract Biomaterials had been comprehensively studied for many decades. The main focus was to coat a bioactive film on substrate that enhances its wear resistance, corrosion resistance, life span, cell growth, etc. In our present work, powder mixed electrical discharge machining (PMEDM) was employed on 316L stainless steel well known biomaterial for hip and knee replacement to modify the surface using Hydroxyapatite nano-powder mixed dielectric medium. Indigenously developed setup with pump and stirrer for proper circulation of powder during experimentation was used. The momentous parameters enhancing MER (max. 19.01 mg/min.) were current, pulse-on-time along with the addition of HAp nano-powder in the dielectric fluid. Addition of HAp also improves surface finish (0.340µm) of machined surface. SEM analysis revealed the porosity and presence of powder particles on machined surface while formation of intermetallic compounds and bioactive compounds on machined surface validated using XRD technique. The results confirmed that the modified surface with HAp nano-particles offered better biocompatible properties.

Differentiation of osteoclast precursors on gellan gum-based spongy-like hydrogels for bone tissue engineering

Bone tissue engineering with cell-scaffold constructs has been attracting a lot of attention, in particular as a tool for the efficient guiding of new tissue formation. However, the majority of the current strategies used to evaluate novel biomaterials focus on osteoblasts and bone formation, while osteoclasts are often overlooked. Consequently, there is limited knowledge on the interaction between osteoclasts and biomaterials. In this study, the ability of spongy-like gellan gum and hydroxyapatite-reinforced gellan gum hydrogels to support osteoclastogenesis was investigated in vitro. First, the spongy-like gellan gum and hydroxyapatite-reinforced gellan gum hydrogels were characterized in terms of microstructure, water uptake and mechanical properties. Then, bone marrow cells isolated from the long bones of mice and cultured in spongy-like hydrogels were treated with 1,25-dihydroxyvitamin D3 to promote osteoclastogenesis. It was shown that the addition of HAp to spongy-like gellan gum hydrogels enables the formation of larger pores and thicker walls, promoting an increase in stiffness. Hydroxyapatite-reinforced spongy-like gellan gum hydrogels support the formation of the aggregates of tartrate-resistant acid phosphatase-stained cells and the expression of genes encoding DC-STAMP and Cathepsin K, suggesting the differentiation of bone marrow cells into pre-osteoclasts. The hydroxyapatite-reinforced spongy-like gellan gum hydrogels developed in this work show promise for future use in bone tissue scaffolding applications.

Microstructural and Mechanical Properties of Al<sub>2</sub>O<sub>3</sub>/HAp Composites for Use as Bone Substitute Material

This work involved the development of alumina/hydroxyapatite (Al2O3/HAp) composites for use as bone graft material in maxillofacial reconstruction. The effect of introducing 20 and 30 wt% of hydroxyapatite into the alumina matrix was also investigated. The composites were produced from hydroxyapatite synthesized by the precipitation method, using commercial alumina as a matrix. Samples of the composite material were compacted under 260 MPa of isostatic pressure, followed by sintering at 1200°C/2h and characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diametral compression. The XRD results confirmed the presence of Al2O3 and Ca10(PO4)6(OH)2 – HAp crystalline phases in all composites. The addition of HAp to the alumina matrix inhibited alumina grain growth, reducing intergranular porosity and thus promoting greater densification and mechanical strength of the composites.

Development of Novel Biocomposite Scaffold of Chitosan-Gelatin/Nanohydroxyapatite for Potential Bone Tissue Engineering Applications.

In this study, a three-dimensional chitosan-gelatin/nanohydroxyapatite (ChG/nHaP) scaffold was successfully fabricated and characterized in terms of swelling, degradation, cell proliferation, cell attachment, and mineralization characterizations. The ChG/nHaP scaffold was fabricated with a mean pore size of 100–180 μm. Our results showed that the physicochemical and biological properties of the scaffolds were affected by the presence of HaP. The swelling and degradation characteristics of the ChG scaffold were remarkably decreased by the addition of HaP. On the other hand, the presence of HaP remarkably improved the MC3T3-E1 cell attachment and cell growth in the scaffold membrane. The biocompatible nature of the ChG/nHaP scaffold leads to the development of finely scaled mineral deposits on the scaffold membrane. Thus, HaP played an important role in improving the biological performance of the scaffold. Therefore, the ChG/nHaP scaffold could be applied as a suitable material for bone tissue engineering applications.

Effect of hydrated apple powder on dough rheology and cookies quality

Dietary fiber is a group of food components, which are resistant to human enzymatic digestion. The incorporation of dietary fiber obtained from various sources of fruit and vegetable by-products into the cereal based products such as bread, rolls, cookies, muffins, crackers, cakes and pasta is of growing interest for the food industry. The replacement of wheat flour by dietary fiber from various sources can change physicochemical, textural and organoleptic characteristic of bakery products. Apple pomace is the main by-product produced in the apple fruit processing industry. It is a rich source of carbohydrate, pectin, crude fiber, and minerals. The dietary fiber content in apple pomace ranges between 33 - 35%. The influence of hydrated commercial dietary fiber on wheat dough rheology (5, 10 and 15% flour replacement) and physical and sensory properties of cookies was examined. It was found that addition of HAP significantly increased the rheological properties of dough such as water absorption (from 58.0% to 75.3%), dough stability (from 6.7 min to 11.6 min) and prolonged dough development time (from 3.5 min to 11.0 min) and reduced the mixing tolerance index (from 34.7 BU to 11.9 BU). It was also concluded that hydrated apple powder addition reduced physical properties of cookies such as volume (from 10.4 cm3 to 8.0 cm3), diameter (from 4.7 cm to 4.2 cm), volume index (from 1.35 cm to 1.10 cm) and porosity (from 0.32 to 0.24). Sensory properties (taste, odour, stickiness, firmness and density) of cookies were also analysed. Cookies with addition of hydrated apple powder had fruity taste and odour and showed high overall acceptance. From this study resulted that hydrated apple powder can be used as potentially source of dietary fiber in cookie formulation. Moreover, addition of apple pomace inhibits the use of any other flavouring ingredients because has a pleasant fruity flavour.

A novel pH‐sensitive ceramic‐hydrogel for biomedical applications

Innovations on the field of smart hydrogels are now being held with loads of advantages. With recent progress, smart polymers can now be used on the market for specific target/objectives desired on medicine. However, the field of smart hydrogels has not been fully overviewed on the ground for drug delivery. In this study, a novel pH‐sensitive smart hydrogel for drug delivery was investigated. Polyvinyl‐alcohol (PVA) with polyacrylic acid (PAA) was blended adding synthetic hydroxyapatite (Hap) with freeze‐thawed cycles and its effects were studied in terms of mechanical strength, bioactivity, and drug release profile. Mechanical strength towards compression tests was decreased after addition of Hap and storage modulus (G') increased. Bioactivity was confirmed after 14 days on simulated body fluid (SBF). Improvement of swelling and gel fraction with the addition of Hap throughout the polymer matrix. Moreover, a study was performed with theophylline‐loaded samples for drug‐delivery studies. Copyright © 2015 John Wiley & Sons, Ltd.