Hydroxyapatite Materials Research Articles

Controlled nanoparticle synthesis of Ag/Fe co-doped hydroxyapatite system for cancer cell treatment

Diagnosis of cancer by chemotherapy treatment, severe side effects caused by high dosages of cancer drugs include non-controlled cytotoxicity to bone marrow cells and immune cells. To overcome, we have synthesized nanoparticles with controlled sized hydroxyapatite (nHAp) materials doped and co-doped with silver and iron by co-precipitation, yielding materials that can treat both the infections and malignant tumors with non-cytotoxic nature to normal cells. Spherical and rod like morphologies were observed for the samples with higher Ag+ doping concentrations with average size of 50 ± 5 nm and (75 × 22) ± 5 nm2, whereas higher Ag+/Fe2+ co-doping concentrations yielded samples with spherical, rod-like, and flake-like structures. For samples nHAp and Ag+-nHAp samples were diamagnetic, whereas the Fe2+-nHAp and Ag+/Fe2+ co-doped samples were superparamagnetic. The in vitro biological toxicity study revealed that the Ag+/Fe2+-nHAp nanoparticles are effective for targeting to kill cancerous cells, for example, human cervical cancer (HeLa) cells efficiently while they are non-toxic to normal cells. Applying these nanoparticles for drug delivery system, 5-fluorouracil was loaded in the nanoparticles and studied its release kinetics. In the case of Ag+/Fe2+co-doped nHAp samples, a pulsatile drug release profile was observed, which the drug was released for about a week on varying the Ag+ and Fe2+ concentrations. The 5-fluorouracil release kinetics was well fitted by the first-order model with diffusion. Thus, nHAps co-doped with Ag+/Fe2+ material have the potential to lag the time on delivering the drug at site-specific could be with an application in biomedicine such as to treat malignant tumor without any bacterial side effect.

Влияние имплантации ионов Ag2+ и C+ на поверхностные физико-химические свойства полилактида, гидроксиапатита и композиционных материалов на их основе

Влияние имплантации ионов Ag2+ и C+ на поверхностные физико-химические свойства полилактида, гидроксиапатита и композиционных материалов на их основе

Antibacterial bone substitute of hydroxyapatite and magnesium oxide to prevent dental and orthopaedic infections

Bone substitutes market is growing due to the great demand for bone regenerative therapies. However, most of the actual products available in the market are incapable of inhibiting bacterial colonization, which can lead to tissue infection and possible implant failure. Some bone substitutes are combined with antibiotics to avoid the development of implant-associated infections, but the growing bacterial resistance to antibiotics often makes these products ineffective. Therefore, it is mandatory to develop new and alternative approaches. In the present work, a granular bone substitute of hydroxyapatite was produced, where different percentages of magnesium oxide were introduced. The antibacterial activity and biofilm formation was evaluated towards Staphylococcus aureus and Escherichia coli. The inclusion of magnesium oxide particles reduced bacterial growth and biofilm formation in a concentration-dependent manner, when compared with pure hydroxyapatite materials. Superior antibacterial activity and inhibition of biofilm formation was observed for Staphylococcus aureus with complete eradication when magnesium oxide percentages were equal or above 3 wt%. The materials cytotoxicity was assessed under ISO 10993-5:2009 guidance and through Live/Dead cell marking and none of the produced granules was cytotoxic. In addition, reactive oxygen species production was also evaluated and the results revealed that the exposure to the materials extracts did not induce the formation of reactive oxygen species by cells.

Analytical Characterization and Potential Antimicrobial and Photocatalytic Applications of Metal-Substituted Hydroxyapatite Materials

Four metal substituted hydroxyapatites (HAPs) were prepared and characterized using energy-dispersive X-ray fluorescence, X-ray diffraction, thermal analysis, and transmission electron microscopy. From the evaluation of the potential applications for antimicrobial properties and the photodegradation of methylene blue, it can be concluded that the two applications seem to be competing. Thus, Mn-substituted HAP, which provided the best degradation efficiency for methylene blue from the substituted materials (approximately 88%), has poor antimicrobial potential against most of the studied microbial lines. The Co-substituted HAP showed favorable antimicrobial properties against all the studied lines, including the lowest values for both minimum inhibitory concentration and a minimal concentration for biofilm eradication of 78.1 µg/mL against Pseudomonas aeruginosa, but exhibited a low degradation efficiency for methylene blue (approximately 42%). This can be explained by the properties of the pure material: pure HAP that showed the highest degradation efficiency of methylene blue (93%) but exhibited no antimicrobial efficiency against the studied lines. Thus, from the performed experiments, a single material cannot be recommended for both applications, but rather a specific material should be employed for each potential use: HAP, Mn- or Sn-substituted HAP for photodegradation, and Co-substituted HAP for antimicrobial applications.

Biomimetic Coating of a Titanium Substrate with Silicon-Substituted Hydroxyapatite

Silicon-substituted hydroxyapatite (Si-HA) materials have been synthesized from a model SBF solution with different concentrations of silicon ions. All of the samples prepared from an extracellular fluid solution at different concentrations of silicate ions have been shown to be single-phase and consist of hydroxyapatite. The nature of the silicon-containing reagent (Na2SiO3 or tetraethyl orthosilicate) has no effect on the structure of hydroxyapatite. Analysis of silicon-modified phosphate coatings on titanium substrates indicates that more complete Si-HA deposition occurs on etched samples during the first three days of holding in the model solution. After exposure of Si-HA-coated titanium substrates to a high-power ion beam, further crystal growth and surface regeneration are possible.

Synthesis and structure properties of Se and Sr co-doped hydroxyapatite and their biocompatibility

The aim of this study is to obtain novel selenium and strontium co-doped functional hydroxyapatite (Se–Sr-HA) material, which may play a potential role in inducing new bone formation and inhibiting the recurrence of cancer for osteocarcinoma patients. Se–Sr-HA was successfully synthesized by chemical precipitation method. The physicochemical and structural properties of the co-doped samples were well characterized by X-ray fluorescence spectroscopy, X-ray diffraction (XRD), Rietveld refinement, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and so on. The XRD studies revealed that the characteristic peaks were consistent with hydroxyapatite, and no other phases or impurities were detected. The SEM observations suggested that the doping component reduced the crystallization of the samples and reduced the particle size. Rietveld refinements were performed to show the change of crystal structure after co-doping. It’s found that co-doping increased the lattice parameter a and c. The thermal stability of the co-doped samples related to the actual amount of incorporated ions. In addition, the biocompatibility of Se–Sr-HA samples and their inhibitory effect on osteosarcoma cells also make them have potential applications in biomedical materials.

Facile synthesis of hydroxyapatite nanoparticles mimicking biological apatite from eggshells for bone-tissue engineering.

A facile synthesis of hydroxyapatite (HAp) nanoparticles that mimicked biological apatite by utilizing eggshells as a bio-calcium precursor was presented via the hydrothermal method and with the assistance of cetyltrimethylammonium bromide for bone-tissue engineering. The synthesized HAp was characterized by the X-ray powder diffraction method, Fourier transform infrared spectroscopy, field emission scanning microscopy, energy-dispersive X-ray spectroscopy, and nitrogen adsorption-desorption isotherms. The HAp nanoparticles were produced in film and pellet forms to determine their biomineralization and protein adsorption through in vitro studies in simulated body fluids and minimum essential medium supplemented with fetal bovine serum, respectively. A pure HAp nanocrystalline phase with rod-shaped nanoparticles of 161 nm in mean length and 52 nm in mean diameter was produced. The HAp was revealed to be a carbonated HAp exhibiting A- and B- type CO32- substitutions with CO32- content of 2.14 ± 1.36 wt.%, trace amounts of some important elements (Mg, Na, and K), and Ca/P atomic ratio of 1.54, thereby confirming that the HAp resembled the biological apatite in terms of morphology, structure, and composition. The HAp showed high biomineralization capability with the quick release of a double layer of bone-like apatite after 3 days in SBF and extremely high protein adsorption with 1213 ± 178 μg of proteins adsorbed on the HAp surface after 24 h. The HAp material had high bioactivity and cell affinity (cell adhesion, spreading, and proliferation). Thus, it has potential as a biomaterial for fabrication of BTE scaffolds. To our knowledge, this article is the first detailed study on biological tests of the HAp material derived from eggshells.

Water-gas shift reaction over a novel Cu-ZnO/HAP formulation: Enhanced catalytic performance in mobile fuel cell applications

CuO-ZnO/HAP catalysts were prepared by co-impregnation and tested in the water-gas shift reaction. The prepared samples were thoroughly characterised by a wide number of analytical techniques including N2 physisorption, XRD, DRS, XPS, H2-TPR, N2O chemisorption, CO-TPD, H2-TPD, CO2-TPD, OSCC and OSC techniques. The properties of the synthesised materials were compared with those of a CuO-ZnO/Al2O3 sample. In contrast to the alumina support, the hydroxyapatite seems to favour the deposition of the CuO and ZnO phases exhibiting an intimate contact. Owing to this suitable distribution and the rich surface chemistry of the support, the CO-TPD, H2-TPD and CO2-TPD data point out that, with independence of the adsorbed molecule, the Cu-ZnO/HAP surface results as the most reactive and provide the largest density of the adsorption sites compared to the Cu-ZnO/Al2O3. The OSCC and OSC data, moreover, show that the former provides relatively high reducibility and larger amounts of reactive oxygen atoms. In realistic WGS reaction conditions the Cu-ZnO/HAP system proves to be highly active and exhibits an excellent stability at 250 °C. The reported data also suggest that the sample with the intermediate copper loading (12 wt.%) represents an optimum chemical composition (Cu/Zn = 3) providing the best catalytic performance. Furthermore, while previous research findings consider the Cu-ZnO as less practical for mobile applications, the current study sheds light on its great potential when supported on hydroxyapatite materials. Indeed, besides its higher activity the CuZn(3)/HAP catalyst successfully withstand the shut-down/start-up conditions exhibiting only 14% activity loss after six cycles. This excellent performance is linked to suitable textural, structural and chemical properties, provided by the HAP support, which make the active sites highly sintering-resistant.

Investigation on Anti-Autofluorescence, Osteogenesis and Long-Term Tracking of HA-Based Upconversion Material

Hydroxyapatite (HA) material will be long-standing once implanted in bone tissue of the body. It should be considered to endow the osteogenic HA material with traceable fluorescence to realize a lifelong in vivo tracking. We prepared and utilized lanthanides-doped HA upconversion material, and revealed for the first time that the lanthanides (ytterbium (Yb) and holmium (Ho)) co-doped HA upconversion material was suitable for long-term or lifelong in vivo tracking, the lanthanide ions doped in the HA matrix would not affect the biocompatibility and osteogenesis, and the tissue autofluorescence could be effectively avoided by the HA:Yb/Ho upconversion material. Also the distribution in bone and osteointegration with bone of the HA:Yb/Ho material could be clearly discriminated by its bright fluorescence under NIR irradiation. The upconversion characteristic of the HA:Yb/Ho material provides a feasibility and promising prospect for lifelong in vivo tracking, and has an advantage in revealing the material-tissue interrelation. The material has important clinical application value in addition to its usefulness for scientific investigation.

SYNTHESIS AND CHARACTERIZATION HYDROXYAPATITE FROM CALCIUM OXIDE (CAO) CHICKEN EGG SHELL WITH PRECIPITATION METHOD

Hydroxyapatite is a constituent compound of tissues in the body such as bones and teeth that can be synthesized from eggshells that have high calcium content. Hydroxyapatite is biocompatible so it can be used as a dental implant. The purpose of this research is to utilize eggshell waste to be synthesized into hydroxyapatite material as base material of dental implant. Hydroxyapatite was synthesized from eggshell nanoparticles calcium oxide (CaO) by mixing HCl, NH3 and Na 3 PO 4 solutions using precipitation method. The synthesis was carried out by 4 samples with the molarity of Na 3 PO 4 4 varied samples ie 4M, 5M, 6M and 7M then calcined at 750 ° C for 4 hours. The results of XRD characterization, showed that the highest Hydroxyapatite content was found in the addition of Na 3 PO 4 5M ie 58 wt%. The crystalline morphology of SEM (Scanning Electron Microscopy) characterization shows that the hydroxyapatite sample has a regular structure and uniform crystal size, while the EDS analysis shows the most dominant CaO content with a grade of 55.91%. Article DOI: https://dx.doi.org/10.20319/mijst.2018.42.4045 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.

Chemical Self-Assembly of Multifunctional Hydroxyapatite with a Coral-like Nanostructure for Osteoporotic Bone Reconstruction.

Bone defects/fractures are common in older people suffering from osteoporosis. Traditional hydroxyapatite (HA) materials for osteoporotic bone repair face many challenges, including limited bone formation and aseptic loosening of orthopedic implants. In this study, a new multifunctional HA is synthesized by spontaneous assembly of alendronate (AL) and Fe3O4 onto HA nanocrystals for osteoporotic bone regeneration. The chemical coordination of AL and Fe3O4 with HA does not induce lattice deformation, resulting in a functionalized HA (Func-HA) with proper magnetic property and controlled release manner. The Func-HA nanocrystals have been encapsulated in polymer substrates to further investigate their osteogenic capability. In vitro and in vivo evaluations reveal that both AL and Fe3O4, especially the combination of two functional groups on HA, can inhibit osteoclastic activity and promote osteoblast proliferation and differentiation, as well as enhance implant osseointegration and accelerate bone remodeling under osteoporotic condition. The as-developed Func-HA with coordinating antiresorptive ability, magnetic property, and osteoconductivity might be a desirable biomaterial for osteoporotic bone defect/fracture treatment.

Collection, compilation and evaluation of elemental and isotopic data of calcium carbonate and hydroxyapatite materials and the assessment of their usability to act as reference materials

Collection, compilation and evaluation of elemental and isotopic data of calcium carbonate and hydroxyapatite materials and the assessment of their usability to act as reference materials

First-principles study on the hydroxyl migration from inner to surface in hydroxyapatite

Understanding to the surface structure of hydroxyapatite (HAp) is crucial for the design of HAp-based biomaterials. While most bioactive HAp materials have disordered structures, the ordered surface structures relaxed from HAp crystal are commonly used for studying their interaction with biomolecules. Using a combined approach of molecular dynamics simulated annealing simulations and density functional theory calculations, we proposed a disordered surface structure model for HAp. In this model hydroxyls beneath the surface move outward and cover the exposed calcium ions. The destabilization caused by hydroxyl vacancy is compensated by the stabilization of hydroxyl coverage. The Ca-exposed surface with strong electrophilicity changes into the hydroxyl- and phosphate-covered surface with moderate activity. The new surface model would be useful for regulating the surface activity of HAp-based biomaterials.

A Facile chemical route to synthesize Zn doped hydroxyapatite nanorods for protein drug delivery

Porous and hollow hydroxyapatite (HAp) materials are widely used in the field of protein drug delivery. However, few studies have examined the systematic adsorption and sustained release ability of proteins on the one-dimensional HAp. In this work, undoped HAp and a series of zinc (Zn)-containing hydroxyapatite (ZnHAp) were prepared by a simple hydrothermal process as protein drug carriers. The phase analysis, surface functional groups, morphologies and zeta potentials of the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Nano-ZS Zetasizer. The characterization results were found that the crystal structures and chemical functional groups of ZnHAp were similar to those of HAp. And all samples doped with Zn exhibited a uniform rod-like morphology, while the HAp consisted of nanobelts. When the Zn concentration increased, the particle size and lattice parameter of ZnHAp decreased slightly as well as zeta potential. The protein adsorption and release tests indicated that the prepared ZnHAp had a much higher protein payload and the protein-loading amount of 1ZnHAp reached 115.1 mg/g, which was about 3.786 times that of HAp. Moreover, the ZnHAp had a good protein release ability than HAp, using lysozyme (LYS) as the model drug.

Assessment of shear bond strength of Polycarboxylate cement reinforced by different amounts of Hydroxyapatite

This study was done to assess bond strength of Polycarboxylate cement reinforcedby different amount of Hydroxyapatite. In this study a hydroxyapatite materials wereadded to Polycarboxylate cement at different ratios;10%, 15%, 20%, 25% and 30% (by weight ) and the bond strength was detected by construction a cylinders from thesemixed materials, constructed on exposed dentine of human extracted premolar teethand by Zwick’s universal testing machine the bond strength were detected for thesemixed materials. Results showed that the Polycarboxylate reinforced byhydroxyapatite has higher bond strength than conventional Polycarboxylate cementand the hydroxyapatite powder to Polycarboxylate cement powder ratio by weightbest to be 20%. The addition of hydroxyapatite to conventional Polycarboxylatecement increased its bond strength to dentine.

Effect of processing techniques on properties of porous TiO2 and TiO2/hydroxyapatite composites

This work focuses on studying the effect of processing routes, namely; starch consolidation and freeze gelcasting techniques on the properties of porous TiO2 and TiO2/5-wt% hydroxyapatite (HA) materials sintered at 1100 °C. The proposed routes were used to control pore characteristics and microstructure of prepared porous structures to be used for biomedical, membranes and environmental applications. Starch and tertiary butyl alcohol (TBA) were used as pore forming agent in the proposed methods, respectively. Phase composition, physical properties, microstructure, compressive strength, and pore size distribution of fabricated materials were investigated. The results indicated that both methods were suitable for production of porous structures with good properties. The samples fabricated by freeze gelcasting route showed improved properties as compared with those prepared by starch consolidation technique due to their improved pore characteristics (homogenous pore size and pore-size distribution) and microstructure. TiO2/HA composites prepared by both methods had lower porosity and mechanical properties than those prepared from pure TiO2.

Biodegradable Drug-Loaded Hydroxyapatite Nanotherapeutic Agent for Targeted Drug Release in Tumors.

Tumor-targeted drug delivery systems have been increasingly used to improve the therapeutic efficiency of anticancer drugs and reduce their toxic side effects in vivo. Focused on this point, doxorubicin (DOX)-loaded hydroxyapatite (HAP) nanorods consisting of folic acid (FA) modification (DOX@HAP-FA) were developed for efficient antitumor treatment. The DOX-loaded nanorods were synthesized through in situ coprecipitation and hydrothermal method with a DOX template, demonstrating a new procedure for drug loading in HAP materials. DOX could be efficiently released from DOX@HAP-FA within 24 h in weakly acidic buffer solution (pH = 6.0) because of the degradation of HAP nanorods. With endocytosis under the mediation of folate receptors, the nanorods exhibited enhanced cellular uptake and further degraded, and consequently, the proliferation of targeted cells was inhibited. More importantly, in a tumor-bearing mouse model, DOX@HAP-FA treatment demonstrated excellent tumor growth inhibition. In addition, no apparent side effects were observed during the treatment. These results suggested that DOX@HAP-FA may be a promising nanotherapeutic agent for effective cancer treatment in vivo.

Tailoring the structural and morphological properties of hydroxyapatite materials to enhance the capture efficiency towards copper(ii) and lead(ii) ions

This study deals with the use of calcium hydroxyapatite (HAP) materials as adsorbents for removing heavy metal ions from polluted waters.

The ultrasound effect on the morphological properties of hydroxyapatite

The present study considers the morphological and dispersity characteristics of hydroxyapatite (HAp) samples synthesised through the ultrasound-assisted hydrothermal method with additional pressure treatment. The samples were analyzed by the X – Ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption. The ultrasound effect on the HAp morphologiy and dispersity was studied. The pressure assisted ultrasonic treatment made possible obtaining HAp samples with different morphology from rods and flakes to particles with irregular shape close to spherical. Also pressure assisted ultrasonic treatment able to increase the porosity of HAp materials.

Evaluation of Maxillary Sinus Floor Augmentation on Digital Panoramic Radiographs with an Image Manipulation Programme after Simultaneous or Staged Dental Implant Insertion

Sinus floor augmentation is an effective method to regain bone height for the successful insertion of dental implants into the posterior maxilla. The aim of the study was to evaluate the behaviour of augmentation material following simultaneous or staged dental implant insertion, as visible on digital panoramic radiographs using the GNU Image Manipulation Program (GIMP). We evaluated one-stage (group 1) or two-stage (group 2) maxillary sinus floor augmentation procedures in 19 patients, using a high temperature-treated bovine porous hydroxyapatite material. Digital panoramic radiographic measurements were captured pre-operatively in both groups, pre-implant insertion in group 2, and immediately postoperatively and 6 months postoperatively in both groups. Forty parallel-walled bone-level implants were placed in a one-stage (n=18) or two-stage (n=22) protocol, with a mean residual bone height of 4.9±1.8 mm and survival rate of 100%. Mean bone height increased by 8.6±1.6 mm immediately post-implantation and by 7.9±1.7 mm after 6 months. Mean distal and mesial bone losses after abutment connection were 0.42±0.24 mm and 0.34±0.27 mm, respectively. No significant intergroup or intragroup differences between simultaneous and staged dental implant procedures were found. Our results show that the histogram tool in GIMP is useful for documentation of the area of the augmentation material used in maxillary sinus floor augmentation.