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PL
W artykule przedstawiono metodę oraz wyniki badań obejmujące próbę dostosowania przyrostowej technologii selektywnego łączenia ziaren proszku do wytwarzania indywidualizowanych ceramicznych uzupełnień ubytków kostnych z zastosowaniem syntetycznego hydroksyapatytu. W dobie intensywnego rozwoju nowoczesnych technologii wytwórczych pojawia się coraz więcej możliwości ich wykorzystania w medycynie, szczególnie z uwagi na zapewnienie precyzyjnego odwzorowania anatomii pacjenta, opartego na danych pochodzących z obrazowania medycznego. Przyrostowe wytwarzanie znalazło już zastosowanie w wytwarzaniu trójwymiarowych modeli fizycznych umożliwiających szczegółową analizę skomplikowanych przypadków oraz służących do planowania i symulacji operacji w celu zmniejszenia ryzyka oraz skrócenia czasu trwania zabiegu. Znane są również przypadki przeprowadzenia implantacji z wykorzystaniem indywidualizowanych implantów. Najczęściej wykorzystywanym materiałem w takich przypadkach są stopy tytanu, co niesie liczne ograniczenia: brak dopasowania własności mechanicznych, brak degradacji czy niepożądane reakcje obronne organizmu. Z tego powodu nieustannie trwają badania nakierowane na wytwarzanie bioakceptowalnych i biodegradowalnych materiałów, które posłużą wytwarzaniu czasowych konstrukcji wspomagających odbudowę naturalnej tkanki w miejscach ubytków. W artykule zaprezentowano metodę wytwarzania oraz przygotowania wszczepów z zastosowaniem biomateriału ceramicznego. W ramach prowadzonych badań wykonano analizę oraz dobrano odpowiednie materiały, parametry procesowe i przeanalizowano ich wpływ na jakość wytwarzanych modeli. Otrzymany w przygotowanej metodzie materiał do zastosowań medycznych poddano testom in vitro, w celu weryfikacji właściwości biologicznych.
EN
The paper presents the method and results comprising adjustment of the incremental technology of selective connection of the powder particles. It is used for the manufacturing of ceramic restorations of individualized bone defects based on synthetic hydroxyapatite. In the era of intensive development of modern technologies of manufacturing, there are more and more opportunities to use their extensive capabilities in medicine, particular by the precise mapping of the patient’s anatomy based on data from medical imaging. Incremental manufacturing has already found application in the manufacture of three-dimensional physical models enabling a detailed analysis of complicated cases and used for planning and simulation of operations to reduce the risk and duration of treatment. There are also known some cases of carrying out the implantation with the use of individualized implants. The most commonly used material in such cases are titanium alloys which cause many restrictions i.e., no matching of mechanical properties, lack of degradation or adverse reactions of the body’s defenses. For this reason, many research is being continuously conducted focusing on manufacturing bioacceptable and biodegradable materials, which will be used in manufacture of temporary structures supporting the restoration of the natural tissue in places of cavities. This paper presents a method of manufacturing and preparing implants using ceramic biomaterial. In this study, appropriate materials as well as process parameters have been chosen and their impact on the quality of the generated models was analyzed. Obtained material for medical use has been tested in vitro to verify biological properties.
EN
A comparison of poly(l-lactide) (PLLA) and poly(l-lactide)/hydroxyapatite (PLLA/HAp) biocomposite microspheres fabricated by emulsion solvent evaporation technique designed for laser sintering (LS) applications is presented. Key properties such as thermal and structural as well as geometry, size distribution and powder flowability, which are crucial for this technique, are characterized to validate the applicability of microspheres for LS. The biocomposite microspheres turns out to be more suitable for the LS process than PLLA due to the higher thermal stability, broader sintering window and higher powder flowability.
PL
Porównano właściwości mikrosfer z poli(l-laktydu) (PLLA) i z biokompozytu poli(l-laktyd)/ hydroksyapatyt (PLLA/HAp), przygotowanych metodą emulsyjną z odparowaniem rozpuszczalnika, przeznaczonych do procesu spiekania laserowego (LS). W celu weryfikacji przydatności mikrosfer do LS scharakteryzowano kluczowe dla tej techniki właściwości: termiczne i strukturalne oraz geometrię, rozkład wymiarów i sypkość proszku. Wykazano, iż mikrosfery biokompozytowe wykazują lepsze właściwości predestynujące je do przetwarzania metodą LS niż mikrosfery PLLA, w tym większą stabilność termiczną, szersze okno parametrów spiekania i większą sypkość proszku.
EN
Metalic materials intended for bone implants should exhibit not only appropriate mechanical properties, but also high biocompatibility. The surface treatment modifications, for example acidic treatment, laser treatment, ion implantation and deposition of highly biocompatible coatings, are practiced. One of the most popular methods of surface modification is to deposit hydroxyapatite (HAp) coatings. HAp naturally occurs in human body, but can be also synthesized in laboratory conditions. Among diverse deposition techniques, electrophoretic deposition (EDP) is a cost-effective method in which charged particles, dispersed in an organic medium, after applying voltage migrate to the counter charged electrode forming a thin coating. There are several parameters that can be controlled during the process and that directly affect the morphology of the surface. The zeta potential and pH of prepared colloidal suspension are closely related to suspension stability and affect the susceptibility for agglomeration of the particles. Electrical settings, especially applied voltage, affect primarily the mass of deposition, but also the porosity of the coating, as well as its homogeneity. One of the basic parameters of EDP method is time of process. With increasing process time, the thickness of the deposited coating increases. Importantly, its mechanical properties also decrease. Moreover, the particles shape and size also affect the morphology of the deposited coating. The analysis of many variables is necessary to choose the right parameters to obtain the coating with desired morphology. In this paper, the influence of each parameter on the morphology of hydroxyapatite coatings is discussed.
PL
W artykule omówiono parametry procesu osadzania elektroforetycznego (EDP) ze szczególnym uwzględnieniem wykorzystania tej metody do osadzania powłok hydroksyapatytowych (HAp) na metalicznych implantach kostnych. Bazując na obszernym przeglądzie najnowszej literatury, przedstawiono wpływ każdego z parametrów na strukturę powstającej powłoki.
EN
During the implantation surgery, an infection associated with the biofilm formation may occur. Both the type of the introduced material as well as the implant osseointegration largely determine the effectiveness of bone defect treatment. The materials research is increasingly focusing on improving the osseointegration process. A bacterial biofilm can form on any surface of the artificial organ that has been introduced into the body or surrounding tissues. A bacterial infection is one of the most serious complications of implantology surgery leading to serious physiological damage. As proved in the literature, a solution that can prevent bacterial infections is to modify the implant surface by applying an antibacterial coating, while maintaining the material biocompatibility. The article presents the tests results of prototype implants with hydroxyapatite coatings obtained via plasma spraying on titanium surfaces. The resulting coatings were enriched with silver nanoparticles, the content of which was about 2%. The animal model are New Zealand rabbits. The implants were placed in the femur of the animal. The amount of released ions and the force of pulling the implants from the bone were determined. The binding strength between the joint surface and the implant was determined by the mechanical blocking and biological binding of growing bone tissue. In addition, the surface structure of the obtained implants was evaluated. It has been shown that the surface modification of the implants affected the obtained stabilization value, as compared to the implants surface coated only with hydroxyapatite.
5
Content available ZrO2 Gelcast Foams Coated with Apatite Layers
EN
In this work, gel-casting of foams method was used to produce ZrO2 porous ceramics. The obtained foams with total porosity of 89.5 vol% were composed of approximately spherical cells having the mean diameter of 537 ± 153 μm interconnected by circular cell windows having the mean diameter of 152 ± 82 μm. Next, the ZrO2 foams were coated with fluorapatite (FA) and hydroxyapatite (HA) layers by slurry infiltration. The intermediate fluorapatite (FA) layer was introduced to prevent the chemical reactions between ZrO2 and HA at high temperatures during sintering process. The ZrO2 samples containing only HA coatings, were also tested, for comparison. The obtained ceramic biomaterials were subjected to in vitro tests in the simulated body fluid (SBF) solution. The results show that the ZrO2 foams with FA/HA layers possessed better bioactivity than the foams with the HA/HA coating.
EN
In order to enhance bioactive properties of titanium 99.2 used in implantology and various biomedical applications, numerous methods to form tight oxide coatings are being investigated. Some of these interesting techniques for generating TiO2 coatings include: electrochemical methods with anodizing, electric discharge treatment, plasma methods (PVD) and diffusive methods (i.e. oxidation in a fluidized bed). Each method aims to create a thin homogenous oxide coating characterized with thermal stability and repassivation ability in the presence of body fluid environment. However, new methods are still sought for increasing the biocompatibility of the substrate following a change in the intensity of depositing on the oxide coating compounds with high biocompatibility with body tissues, including hydroxyapatite, which constitutes the basis for subsequent osseointegration processes. The article presents investigation of HAp formation on titanium substrate surface after hybrid oxidation process. Hybrid surface treatments combine methods of fluidized bed atmospheric diffusive treatment FADT with the PVD surface treatment realized with different parameters (FADT - 640°C / 8h and PVD - magnetron sputtering with TiO2 target). In order to investigate the effects of hybrid oxidation and the formation of HAp molecules, SEM-EDS, SEM-EBSD, STEM-EDS, RS, nanoindentation and Kokubo bioactivity tests (c-SBF2) were carried out. The hybrid method of titanium oxidation, proposed by the Author, presents a new outlook on themodification and development of the properties of oxide coatings in the area of biomedical applications. Combining the ways of Ti Grade 2 oxidation in the hybrid method highly improves the formation of hydroxyapatite compounds and shows the potential of applying such a technique in implantology, where the intensive growth of bone tissues is crucial.
EN
Hydroxyapatite (HAP) composites are very important biomaterials, which can be applied in various life areas. HAP composite with white clay was prepared and studied using X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR), potentiometric titration, and quasi-elastic light scattering and zeta potential measurements. The values of pHpzc (point of zero charge) and pHIEP (isoelectric point) which characterize the electrical double layer depend strongly on the white clay addition to HAP. Comparative studies of hydroxyapatite, white clay and composite using nitrogen adsorption and FTIR methods showed that in most cases composite has the properties nearly intermediate between hydroxyapatite and white clay taken for the synthesis; however, certain non- additivity was observed analyzing the properties, due to precipitation of HAP onto clay particles that changes the HAP formation conditions in comparison to HAP formation alone. Thus, changes in the condition of the composite preparation allow one to control the properties of the final materials.
EN
Hydroxyapatite (HAp) ceramic materials are consi-dered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important role in improving its structural and physico--chemical properties. HAp doped with niobium ions has not been widely investigated so far. However, the results of studies available in the literature show that the synthesized CaO-P2O5-Nb2O5 compounds still show good biocompatibility, very low cytotoxicity and, additionally, they stimulate osteoblast proliferation. Therefore, this study is dedicated to the niobium--doped HAp ceramics obtained by two methods: mechano-chemical synthesis and sol-gel method. Bioceramics chemical composition, morphology, and structure were characterized by means of scanning electron microscopy imaging, BET method, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicate that nanoceramics of non-stoichiometric HAp with a clear Ca deficiency on the nanograin surface were obtained. Moreover, it has been observed that the presence of Nb dopants and the synthesis method directly affect unit cell parameters, crystallinity degree, crystallites size, porosity and distribution of niobium in the grain structure. Mechano-chemical synthesis has allowed effective niobium incorporation into the HAp structure, leading to the quite homogeneous Nb distribution in the grain volume. Whereas, Nb-doping by sol-gel method has led to dopants location mainly on the grain surface.
EN
In this work, we obtained a mesoporous silica-calcium phosphate composite (MSi-CaP) in the form of spherical granules (pellets) loaded with cefazolin as a model antibiotic. First, the MSi-CaP composite was manufactured in the powder form via the sol-gel method using a soft template. The cefazolin was loaded into the MSi-CaP using the immersion method. The pellets were composed of MSi-CaP powders (both placebo and cefazolin-loaded) and excipients, such as microcrystalline cellulose and ethyl cellulose. The pellets were obtained in the laboratory scale using the wet-granulation, extrusion and spheronization method. The pellets proved satisfactory mechanical properties which allowed for further investigations (the drug release studies and the mineralization potential assay) without a risk of pellets cracking. The complete drug release from the pellets was observed after 12 h. The burst release of cefazolin from the pellets was reduced by 3 when compared to the burst release of cefazolin-loaded MSi-CaP powders (90 and 30% after 15 min of release studies, respectively). The pellets showed the mineralization potential in vitro, confirmed by the SEM-EDX and FTIR methods. After 60 days of the mineralization potential assay in the simulated body fluid, the examinations revealed that the whole surface of pellets was covered with the carbonated hydroxyapatite in accordance with the desired morphology.
EN
PMMA-based bone cements are commonly used for implant fixation or as bone void fillers. Hydroxyapatite added as a filler to bone cement may positively affect the final properties of the material, in particular its biological properties. In this study, the preparation of poly(methyl methacrylate)-based bone cements with incorporated hydroxyapatite (HAp) is reported. The purpose of this article is to examine the proper-ties of bone cements enriched with HAp filler (the concentration of 3wt% and 6wt%) and reveal the changes in the composites properties (chemical structure, surface morphology and distribution of HAp in the composite matrix, moisture absorption, hardness in Shore D scale) during the long-term incubation in the PBS (phosphate-buffered saline) solution at 37°C. The incubation lasted up to 21 days, but only the period when the changes actually occurred was analysed. The studies have shown that the samples containing HAp absorb more moisture and have a lower hardness. These characteristics vary depending on the concentration of HAp. There is no elution of HAp and ZrO2 from the composite during the incubation. The surface morphology and chemical structure do not change during long-term studies. The obtained bone cements are characterized by high stability in the PBS solution.
11
Content available remote Sorption of hydrogen chloride in the fluidized bed reactor
EN
Combustion of fuels, including renewable fuels and thermal treatment of waste (CFCs, pesticides), is associated with emissions of pollutants including halogens. The reversible process of sorption/desorption of HCl, in a fluidized (bubbling) bed reactor (BFB), during co-combustion of Cl-materials, was carried out. The thermal decomposition of methylene chloride (DCM, CH2Cl2) in an inert sand bed with the addition of the hydroxyapatite sorbent (HAp, Ca5(PO4)3(OH)) was investigated. The process parameters were as follows: temperature - 930 °C, the air excess - 1.3, stream rate of CH2Cl2 - 50 cm3/h. The concentration of HCl, CCl4, CHCl3, CH2Cl2, CH3Cl, COCl2 in the exhaust gases were monitored online with FTIR spectroscopy. The main chlorine product was hydrogen chloride. Samples of unprocessed HAp, taken from the bed during the process, and solid apatite residues were analyzed by X-ray diffraction (XRD). The content of chlorapatite (Ca5(PO4)3Cl) in the analyzed samples was respectively 11, 53 and 19 %. X-ray fluorescence (XRF) analysis showed the molar ratio of Ca:P:Cl was: 1.00:0.36:0.01, 1.00:0.36:0.09, 1.00:0.37:0.04 respectively. The HAp could be used as an sorbent of the HCl(g) during combustion of materials containing chlorine.
EN
Nanocrystalline apatites Ca10(PO4)6(OH)2 (HAp) non-doped and doped with Ag+ and Eu3+ ions were synthesized by different wet chemistry methods. The obtained hydroxyapatite was loaded with Ag0, as well as nitroimidazole antimicrobials: metronidazole and tinidazole. The antimicrobial activity of the obtained materials against Prevotella bivia and Parabacteroides distasonis was studied. The method used for the antibacterial susceptibility testing was broth microdilution, according to the CLSI – Clinical and Laboratory Standard Institute – standard M11-A8; agar Schaedler, enriched with 50% LHB - Lysed Horse Blood, was used as a medium for culturing strains. The antibacterial activity increased for the immobilized antibiotics – HAp doped with metronidazole and tinidazole was six times more bactericidal than non-immobilised metronidazole for both clinical isolates. In comparison with non-immobilised tinidazole, HAp immobilised with tinidazole was six thousand times more effective against P. distasonis and two hundred times more effective against P. bivia. HAp doped with tetracycline was over two times more bactericidal than tetracycline non-immobilised (according to the literature data). The exact MIC for bionanocomposites of HAp and silver was not obtained. The research shows that bionanocomposites of hydroxyapatite are good drug carriers for both antibiotics and silver particles and ions. The use of bionanocomposites of apatite immobilised with antibiotics in dentistry could result in a prolonged antibacterial activity of these compounds.
EN
The study of the kinetics and statics of cobalt adsorption at the hydroxyapatite/electrolyte interface using radioactive isotope 60Co was conducted. The course of adsorption kinetics indicates that at the beginning adsorption proceeds quickly and then slowly. Such adsorption kinetics is best described by a multiexpotential equation. The analysis of cobalt adsorption as a function of pH and the results of H+ ions desorption/adsorption confirmed that cobalt adsorption proceeds due to ion exchange with calcium ions in the crystal lattice and hydrogen ions in the surface groups of hydroxyapatite. Cobalt ions adsorption results in the increase of the electrokinetic potential but for the solution of the initial concentration of 0.001 mol/dm3 at pH = 8.17 a reversal of the charge due to overloading of the compact layer (edl) is observed.
EN
AISI 316L–hydroxyapatite biomaterials were produced by the conventional powder metallurgy technology. In the case of materials such as these, proper and long-term functioning in the aggressive environment of body fluids is very important. Therefore, the purpose of this study was to determine the effect of hydroxyapatite content and sintering temperature on the properties including sintered density, open porosity, and in particular corrosion resistance of AISI 316L–hydroxyapatite biomaterials in Ringer’s solution. The measurement of sintered density and open porosity of studied materials was carried out by the water-displacement method. The corrosion behaviour was studied by open circuit potential measurement and potentiodynamic polarization method. It was stated that the properties of studied biomaterials are dependent on chemical composition of powders mixture and sintering temperature. The results showed that higher sintering temperature ensured to obtain lower values of corrosion current density and corrosion rate, and higher value of polarization resistance. The addition of 5 wt % hydroxyapatite provided to a significant improvement of corrosion resistance in Ringer’s solution in comparison to AISI 316L steel, while a slight decrease in corrosion resistance was observed for AISI 316L–10 wt % hydroxyapatite biomaterials. Passivation ability and better corrosion resistance indicate that sintered at 1240°C AISI 316L–5 wt % hydrohyapatite biomaterials is more appropriate for long-term functioning implants than AISI 316L steel. This biomaterial possessed good densification and the best corrosion resistance among all studied materials, as evidenced by the lowest corrosion current density and corrosion rate combined with the highest polarization resistance.
PL
W przypadku biomateriałów właściwe i długotrwałe funkcjonowanie w agresywnym środowisku płynów ustrojowych jest bardzo ważne. Austenityczne stale nierdzewne przy dobrych właściwościach mechanicznych wykazują jednak znaczną podatność na korozję elektrochemiczną, natomiast hydroksyapatyt charakteryzuje się bardzo dobrą biozgodnością i odpornością na korozję. Wprowadzenie dodatku hydroksyapatytu może wpłynąć na poprawę odporności korozyjnej, biozgodności, ale także właściwości tribologicznych stali AISI 316L. W pracy dokonano oceny odporności na korozję w roztworze Ringera spiekanych biomateriałów AISI 316L– hydroksyapatyt. Ponadto określono gęstość i porowatość otwartą otrzymanych materiałów. Na podstawie przeprowadzonych badań potencjodynamicznych i wyznaczonych parametrów korozyjnych określono wpływ zawartości hydroksyapatytu i temperatury spiekania na odporność na korozję badanych materiałów.
PL
Badania dotyczyły zastosowania metody Chemicznego Zapotrzebowania Tlenu (ChZT) do oznaczenia ilości lecytyny związanej z hydroksyapatytem (HAp-LE), otrzymanym w procesie chemicznej precypitacji. Dokładność metody zweryfikowano wykonując bilans tlenu zużytego do całkowitego utlenienia lecytyny zawartej w mieszanie poreakcyjnej, osadzie oraz supematancie. Zawartość lecytyny w proszkach mieściła się w granicach od 1% do 30%. Zaproponowana metoda analityczna może być wykorzystywana do oznaczenia innych dodatków organicznych związanych z syntetycznym HAp.
EN
The research concerned the application of the Chemical Oxygen Demand (COD) method lor determining the amount of lecithin bonded with hydroxyapatite (HAp-LE) obtained in the wet chemical precipitation process. The accuracy of method was verified using a balance of oxygen consumed to completely oxidize the lecithin contained in post-reaction mixture, precipitate and supernatant. The content of lecithin in obtained powders ranged from 1% to 30%. The proposed analytical method can be used in the determination of other organie additives bonded with synthetic HAp.
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