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Advanced high-entropy (Hf-Ta-Zr-Nb-Ti)C ceramics were successfully fabricated by the combination of ball milling and a two-step sintering process at 2100 °C for 5, 10, and 20 minutes from commercially available powders. The microstructure characteristics and mechanical properties of the developed systems were investigated. The high-entropy ceramics exhibit: medium grain size from 8 μm to 11 μm, high compositional uniformity, and high relative density above 99.5 %. Vickers hardness for all systems decreased with increasing applied load, with the highest value HV1 = 22.0 GPa for the system sintered for 5 minutes, while the fracture toughness changed from 2.70 MPa.m1/2 to 3.50 MPa.m1/2. The highest four-point flexural strength of 284 MPa was measured for the system with the smallest grain size.

The powdered cement tetracalcium phosphate/monetite/silk fibroin composite (CFIB) was prepared by simple mechanical milling of tetracalcium phosphate/monetite powder mixture with fibrous soluble silk fibroin (SF). The powder composite cement mixtures contained 5 and 10 wt % of SF and 2% NaH2 PO4 solution with 0.1% genipin was used as a liquid component. The setting time of CFIB cement increased with addition of SF from 5 to 25 min in fully injectable cement with 10 wt % of SF. The compressive strength of hardened composites was reduced to 14 MPa which is close to strength of cancellous bone. The 8% of SF from origin amount in CFIB composites was only desorbed from cements after 7 days soaking in simulated body fluid (SBF). It was found almost full transformation of calcium phosphate components in composite to rod-like nanohydroxyapatite after hardening of CFIB cements in SBF. The SF in hardened cements was present in fine globular form after dissolution, actively affected the fluidity of pastes, morphology of hydroxyapatite particles, and microstructure. The excellent cell proliferation and a high over expression of osteogenic gene markers in MSCs were confirmed after the long-time cultivation in CFIB10 cement extract. Injectable CFIB10 cements have appropriate properties for utilization in bone defect treatments with possible positive effect on healing process.

The chorioallantoic membrane (CAM) is a highly vascularized avian extraembryonic membrane widely used as an in vivo model to study angiogenesis and its inhibition in response to tissues, cells, or soluble factors. In recent years, the use of CAM has become an integral part of the biocompatibility testing process for developing biomaterials intended for regenerative strategies and tissue engineering applications. In this study, we used the chicken

Tetracalcium phosphate/monetite biocement was modified with 10 and 30 wt. % addition of highly porous silicon nitride/α-tricalcium phosphate (αTCP) microgranules with various content of αTCP. A composite cement powder mixture was prepared using mechanical homogenization of basic components. The accelerated release of dexamethasone from composite cement was revealed, which indicates their possible utilization for controlled drug release. The wet compressive strength of cements (

Magnesium pyrophosphate modified tetracalcium phosphate/monetite cement mixtures (MgTTCPM) were prepared by simple mechanical homogenization of compounds in a ball mill. The MgP2O7 was chosen due to the suitable setting properties of the final cements, in contrast to cements with the addition of amorphous (Ca, Mg) CO3 or newberite, which significantly extended the setting time even in small amounts (corresponding ~to 1 wt% of Mg in final cements). The results showed the gradual dissolution of the same amount of Mg2P2O7 phase, regardless of its content in the cement mixtures, and the refinement of formed HAP nanoparticles, which were joined into weakly and mutually bound spherical agglomerates. The compressive strength of composite cements was reduced to 14 MPa and the setting time was 5–10 min depending on the composition. Cytotoxicity of cements or their extracts was not detected and increased proliferative activity of mesenchymal stem cells with upregulation of osteopontin and osteonectin genes was verified in cells cultured for 7 and 15 days in cement extracts. The above facts, including insignificant changes in the pH of simulated body fluid solution and mechanical strength close to cancellous bone, indicate that MgTTCPM cement mixtures could be suitable biomaterials for use in the treatment of bone defects.

Due to the complexity of pathological processes in spinal cord injury (SCI), it is increasingly recognized that combined strategies are more effective than single treatments. The aim of the present study was to enhance neural tissue regeneration and axon regrowth using Rho-A-kinase inhibitor (Y-27632) in a rat SCI model (Th9 compression) and to bridge the lesion with a chitosan/collagen porous scaffold (ChC-PS) applied two weeks after SCI. In addition, to see the synergic effect of Y-27632 and ChC-PS, we combined these single therapeutic strategies to enhance the regenerative capacity of injured spinal cord tissue. The animals survived eight weeks. Application of Y-27632 modulated the inhibitory milieu by specifically targeting gray and white matter integrity, glial fibrillary acidic protein (GFAP)-immunoreactivity, and the outgrowth of neurofilaments and growth-associated protein-43 (GAP-43) immunoreactive axons across the lesion sites, leading to significant positive functional outcome from day 20 to 56. Compared to single treatments, combined Y-27632/ChC-PS therapy was more effective in neurofilaments and GAP-43 expression and GFAP immunoreactivity in the perilesional area of dorsal, lateral and ventral columns, and in enhancing the gray and white matter integrity throughout the cranio-caudal extent. The findings indicate that combined therapy provides a supportive environment for endogenous regenerative processes.

The effect of nanosilica on the microstructure setting process of tetracalcium phosphate/nanomonetite calcium phosphate cement mixture (CPC) with the addition of 5 wt% of magnesium pyrophosphate (assigned as CT5MP) and osteogenic differentiation of mesenchymal stem cells cultured in cement extracts were studied. A more compact microstructure was observed in CT5MP cement with 0.5 wt% addition of nanosilica (CT5MP1Si) due to the synergistic effect of Mg2P2O7 particles, which strengthened the cement matrix and nanosilica, which supported gradual growth and recrystallization of HAP particles to form compact agglomerates. The addition of 0.5 wt% of nanosilica to CT5MP cement caused an increase in CS from 18 to 24 MPa while the setting time increased almost twofold. It was verified that adding nanosilica to CPC cement, even in a low amount (0.5 and 1 wt% of nanosilica), positively affected the injectability of cement pastes and differentiation of cells with upregulation of osteogenic markers in cells cultured in cement extracts. Results revealed appropriate properties of these types of cement for filling bone defects.

This study aimed to clarify the therapeutic effect and regenerative potential of the novel, amino acids-enriched acellular biocement (CAL) based on calcium phosphate on osteochondral defects in sheep. Eighteen sheep were divided into three groups, the treated group (osteochondral defects filled with a CAL biomaterial), the treated group with a biocement without amino acids (C cement), and the untreated group (spontaneous healing). Cartilages of all three groups were compared with natural cartilage (negative control). After six months, sheep were evaluated by gross appearance, histological staining, immunohistochemical staining, histological scores, X-ray, micro-CT, and MRI. Treatment of osteochondral defects by CAL resulted in efficient articular cartilage regeneration, with a predominant structural and histological characteristic of hyaline cartilage, contrary to fibrocartilage, fibrous tissue or disordered mixed tissue on untreated defect (p &lt, 0.001, modified O’Driscoll score). MRI results of treated defects showed well-integrated and regenerated cartilage with similar signal intensity, regularity of the articular surface, and cartilage thickness with respect to adjacent native cartilage. We have demonstrated that the use of new biocement represents an effective solution for the successful treatment of osteochondral defects in a sheep animal model, can induce an endogenous regeneration of cartilage in situ, and provides several benefits for the design of future therapies supporting osteochondral defect healing.

The articular cartilage is an avascular and aneural tissue and its injuries result mostly in osteoarthritic changes and formation of fibrous tissue. Efforts of scientists worldwide are focused on restoration of cartilage with increase in life quality of patients. Novel polymeric polyhydroxybutyrate/chitosan (PCH) porous 3D scaffolds were developed and characterized. The rat mesenchymal stem cells (MSCs) were seeded in vitro on PCH scaffolds by a simple filtration of MSCs suspension over scaffolds using syringe. The chondrogenesis of cell-scaffold constructs was carried out in supplemented chondrogenic cultivation medium. After 2 and 4 weeks of in vitro culturing cell-scaffold constructs in chondrogenic differentiation medium, the cartilage extracellular matrix components like glycosaminoglycans and collagens were identified in scaffolds by biochemical assays and histological and immunohistochemical staining. Preliminary in vivo experiments with acellular scaffolds, which filled the artificially created cartilage defect in sheep knee were done and evaluated. Cells released from the bone marrow cavity have penetrated into acellular PCH scaffold in cartilage defect and induced tissue formation similar to hyaline cartilage. The results demonstrated that PCH scaffolds supported chondrogenic differentiation of MSCs in vitro. Acellular PCH scaffolds were successfully utilized in vivo for reparation of artificially created knee cartilage defects in sheep and supported wound healing and formation of hyaline cartilage-like tissue.

Samarium niobate SmNbO4 (SNO) and tantalate SmTaO4 (STO) precursors were prepared by sol-gel method and annealing at 1000 °C. The different polymorphs, orthorhombic and monoclinic SmNbO4 or tetragonal SmTa7O19 and monoclinic SmTaO4 were identified. Structural properties of precursors were investigated by the X-ray photoelectron spectroscopy (XPS). Core-level XPS studies of sol-gel SNO and STO were performed for the first time. The binding energy differences Δ(O Nb) = BE (O 1s) – BE (Nb 3d5/2) and Δ(O Ta) = BE (O 1s) – BE (Ta 4f7/2) were used as suitable parameter to characterize average Nb O bonding in SNO (323.1 eV) and Ta O bonding in STO (503.9 eV). The Sm 3d5/2 peak consists of strong features characteristic for Sm3+ (1083.0 eV) with (4f5) electron configuration and Sm2+ (1072 eV) with (4f6) electron configuration. The molar concentration of Sm3+ in SNO and STO was higher (21.0 and 24.7 at.%) than Sm2+ in SNO (1.0 at.%) and STO (0.3 at.%). The XPS demonstrated two valence states of Sm in precursors for application as nanophosphors for lighting and display technologies.

Calcium phosphate cements (CPCs) belong to one of the most prominent biomaterials used for filling and regeneration of hard tissues, however poor mechanical and biological properties limit their widespread use in some clinical applications. To solve these problems, a biodegradable glycerol-citrate (G-CA) polyester was synthesized and coated on tricalcium phosphate cement (TCP) powders in amounts up to 10 wt% of the G-CA content using a simple solution infiltration technique in ethanol solution. Chemical and structural analysis of the G-CA elastomer and TCP/G-CA composites were thoroughly analyzed with chromatographic techniques, solid-state nuclear magnetic resonance (ssNMR), differential scanning calorimetry and thermogravimetry (DSC/TG), X-ray diffraction (XRD), Fourier-Transform Infrared spectroscopy (FTIR) and field emission scanning electron microscopy (SEM). The results demonstrated that the incorporation of 2.5 and 5 wt% of G-CA into TCP cement led to a significant increase of mechanical strength of the cements due to the formation of thin and homogeneous elastomer coating on cement particles, reinforcing the microstructure through hydrogen bonds between residual COOH groups of polymer and surface phosphate groups of the cement matrix. Additional in vitro testing of extracts cytotoxicity revealed a high proliferation of osteoblasts in all composites, demonstrating a promising application potential in regenerative medicine.

A modified one-step process was used to prepare tetracalcium phosphate/monetite/calcium sulfate hemihydrate powder cement mixtures (CAS). The procedure allowed the formation of monetite and calcium sulfate hemihydrate (CSH) in the form of nanoparticles. It was hypothesized that the presence of nanoCSH in small amounts enhances the in vitro bioactivity of CAS cement in relation to osteogenic gene markers in mesenchymal stem cells (MSCs). The CAS powder mixtures with 15 and 5 wt.% CSH were prepared by milling powder tetracalcium phosphate in an ethanolic solution of both orthophosphoric and sulfuric acids. The CAS cements had short setting times (around 5 min). The fast setting of the cement samples after the addition of the liquid component (water solution of NaH2PO4) was due to the partial formation of calcium sulfate dihydrate and hydroxyapatite before soaking in SBF with a small change in the original phase composition in cement powder samples after milling. Nanocrystalline hydroxyapatite biocement was produced by soaking of cement samples after setting in simulated body fluid (SBF). The fast release of calcium ions from CAS5 cement, as well as a small rise in the pH of SBF during soaking, were demonstrated. After soaking in SBF for 7 days, the final product of the cement transformation was nanocrystalline hydroxyapatite. The compressive strength of the cement samples (up to 30 MPa) after soaking in simulated body fluid (SBF) was comparable to that of bone. Real time polymerase chain reaction (RT-PCR) analysis revealed statistically significant higher gene expressions of alkaline phosphatase (ALP), osteonectin (ON) and osteopontin (OP) in cells cultured for 14 days in CAS5 extract compared to CSH-free cement. The addition of a small amount of nanoCSH (5 wt.%) to the tetracalcium phosphate (TTCP)/monetite cement mixture significantly promoted the over expression of osteogenic markers in MSCs. The prepared CAS powder mixture with its enhanced bioactivity can be used for bone defect treatment and has good potential for bone healing.

The preparation of the lanthanide metal-organic frameworks LnMOFs (Ln = Eu, Gd, Tb, Eu0.5Gd0.25Tb0.25, Eu0.25Gd0.5Tb0.25 and Eu0.25Gd0.25Tb0.5) by solvothermal synthesis is reported. Three synthesis routes (A, B, C) using different solution (N,N-dimethylforamide (DMF)/H2O/EtOH (A) and with addition of modulator (sodium acetate) to DMF/H2O (B) or EtOH/H2O (C) are presented. Structural characterizations reveal that the coordination effect between Eu3+, Gd3+, Tb3+ ions and 1,3,5-benzenetricarboxylic acid (BTC) ligand in LnMOFs is confirmed. The advantage of green modulation (C) method is creation of rod-like nanocrystals (~50–150 nm). Transparent LnMOF thin films are prepared by dropping of colloidal solution of LnBTC nanocrystals on SiO2/Si substrates with Pt interlayer. Three new ratios of lanthanides (Eu0.5Gd0.25Tb0.25, Eu0.25Gd0.5Tb0.25 and Eu0.25Gd0.25Tb0.5) in mixed films with bidoped concentration of Eu3+/Tb3+ ions in Gd3+ matrix are select. Comparing luminescence properties of Eu0.25Gd0.5Tb0.25BTC powder and film (C method), film provide the quantum efficiency value 8.6 times lower than powder. Eu0.5Gd0.25Tb0.25BTC film present increase of europium mean lifetime by more than 5 times and improvement for quantum efficiency of about 300%, regarding to Eu0.25Gd0.5Tb0.25BTC film and bicolor emission profile depending only of excitation wavelengths. The resulting transparent luminescent LnMOF films can be used in the fabrication of different optical devices.

This study presents the synthesis, structural and luminescence properties for lanthanide metal–organic frameworks (LnMOFs), which belong to the sub-class of coordination polymers. The series of nanosized LnMOFs (Ln = Eu, Gd, Tb, Eu0.5Gd0.5, Tb0.5Gd0.5 and Eu0.5Tb0.5) was prepared by solvothermal synthesis using a modulator (sodium acetate). We investigated the various surface chemistry compositions of the isostructural LnMOFs with a [Ln(btc)] structure (BTC: Benzene-1,3,5-tricarboxylate) by X-ray photoelectron spectroscopy (XPS). The XPS confirmed the mixed-valent Eu3+ and Eu2+ compounds, and the presence of Tb in both +3 and +4 valence states, and one +3 valency of Gd. A nanostructure of mixed LnMOFs (EuGd, TbGd and EuTb) with a rod-like shape is related to luminescence properties. The MOFs (EuTb and EuGd) presented Comission Internationale de l’Éclairage (CIE) chromaticities of x = 0.666 and y = 0.331, and x = 0.654 and y = 0.348, respectively, in the red region. They were better than the values desired for use in commercial phosphors, which are x = 0.64 and y = 0.35. For [Tb/Gd(btc)], the CIE coordinates were x = 0.334 and y = 0.562, presenting emissions in the green region. Bimetallic LnMOFs are very promising UV light sensors for biological applications.

Novel calcium phosphate cements containing a mixture of four amino acids, glycine, proline, hydroxyproline and either lysine or arginine (CAL, CAK) were characterized and used for treatment of artificial osteochondral defects in knee. It was hypothesized that an enhanced concentration of extracellular collagen amino acids (in complex mixture), in connection with bone cement in defect sites, would support the healing of osteochondral defects with successful formation of hyaline cartilage and subchondral bone. Calcium phosphate cement mixtures were prepared by in situ reaction in a planetary ball mill at aseptic conditions and characterized. It was verified that about 30&ndash, 60% of amino acids remained adsorbed on hydroxyapatite particles in cements and the addition of amino acids caused around 60% reduction in compressive strength and refinement of hydroxyapatite particles in their microstructure. The significant over-expression of osteogenic genes after the culture of osteoblasts was demonstrated in the cement extracts containing lysine and compared with other cements. The cement pastes were inserted into artificial osteochondral defects in the medial femoral condyle of pigs and, after 3 months post-surgery, tissues were analyzed macroscopically, histologically, immunohistochemically using MRI and X-ray methods. Analysis clearly showed the excellent healing process of artificial osteochondral defects in pigs after treatment with CAL and CAK cements without any inflammation, as well as formation of subchondral bone and hyaline cartilage morphologically and structurally identical to the original tissues. Good integration of the hyaline neocartilage with the surrounding tissue, as well as perfect interconnection between the neocartilage and new subchondral bone tissue, was demonstrated. Tissues were stable after 12 months&rsquo, healing.

Novel enzymatically hardened tetracalcium phosphate/monetite cements were prepared applying phytic acid/phytase (PHYT/F3P) mixture as hardening liquid after dissolving in acetic acid solution (CX cement). Properties of the cements were compared with classic cement hardened with 2% NaH2PO4 (C cement) and cement hardened with acetic acid solution (CAC cement) only. In the microstructure of CX cement, columnar growth of hydroxyapatite particles was found in the form of walls around hydroxyapatite agglomerates originated from tetracalcium phosphate which were mutually separated by a material depleted low density zone. Wet compressive strengths (CS) of all cements were practically identical contrary to about 30% higher dry CS's of CX and CAC cements due to specific microstructure. It was verified noncytotoxic character of CX cement extracts and positive effect of CX cement on ALP activity and cell behavior during cultivation. The final Ca/P molar ratio and setting time of cement were effectively controlled by the amount of phytic acid and the change in PHYT/F3P mass ratio, or reaction time in hardening liquid, respectively.

Using scaffolds with appropriate porosity represents a potential approach for repair of critical-size bone defects. Vascularization is essential for bone formation and healing. This study investigates methods for monitoring angiogenesis within porous biopolymer scaffolds on the basis of polyhydroxybutyrate (PHB)/chitosan. We use the chick and quail chorioallantoic membrane (CAM) assay as an in vivo model focused on the formation of new blood vessels inside the implant structure. Chemical properties of the surface in biopolymer scaffold matrix were characterized as well as the tissue reaction of the CAM. Implantation of a piece of polymer scaffold results in vascular reaction, documented visually and by ultrasound biomicroscopy. Histological analysis shows myofibroblast reaction (smooth muscle actin-positive cells) without excessive collagen deposition. Cell invasion is observed inside the implant, and QH1 marker, detecting hemangioblasts and endothelial cells of quail origin, confirms the presence of vascular network. The CAM assay is a rapid and easy way to test biocompatibility and vasculogenic potential of new candidate scaffolds for bone tissue bioengineering with respect to the 3R´ s.

The aim was to investigate the enamel health benefits of a novel toothpaste with active tetracalcium phosphate/monetite mixtures under de/remineralization cycling. The enamel de/remineralization cycling protocol was consisted of demineralization in 1% aqueous solution of citric acid at pH 3.6 with following treatment with toothpastes and soaking in remineralization storage solution. Effectiveness of toothpastes to promote remineralization was evaluated by surface microhardness measurements, enamel erosion depth, analysis of surface roughness and fluorescent optical method. The novel tetracalcium phosphate/monetite toothpaste had the same remineralization potential as commercial calcium silicate/phosphate toothpaste and significantly higher than control storage solution group (p0.66). The results showed that dentifrice formulations containing active tetracalcium phosphate/monetite mixture with or without fluoride addition had excellent enamel remineralization potential under de/remineralization cycling and successfully promote remineralization of enamel with daily using in the form of toothpaste.

Gadolinium orthoniobate GdNbO 4 (GNO) and orthotantalate GdTaO 4 (GTO) thin films (∼100 nm) were prepared by sol-gel/spin-coating process on Al 2 O 3 substrates with Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) interlayer and annealing at 1000 °C. The precursors of films were synthesized using Nb or Ta tartrate complexes. We also report for the first time the FTIR, Raman spectra and morphology of tartrate GNO and GTO precursors annealed at various temperatures. The different phase transformation was determined in GNO or GTO precursors from fluorite T′-structure via orthorhombic O-GdNbO 4 or cubic C-GdTa 7 O 19 to monoclinic M-GdNbO 4 or M′-GdTaO 4 during annealing at 800–1200 °C. XRD results of GNO or GTO films confirmed the coexistence of M-GdNbO 4 or M′-GdTaO 4 phase in addition to O-GdNbO 4 (in GNO) or C-GdTa 7 O 19 (in GTO) as main phase at 1000 °C. The surface morphology and topography of thin films were investigated by the SEM and AFM analysis. GNO film was smoother with roughness of 7.31 nm in comparison with GTO (3.53 nm). The results of this work can contribute to the formation different polymorphs of these films for the application to environmental electrolytic thin film devices.

Surface chemical composition of gadolinium niobate GdNbO4 (GNO) and tantalate GdTaO4 (GTO) thin films was examined by X-ray photoelectron spectroscopy (XPS). XPS spectra confirmed Gd3+ and Nb5+ or Ta5+ valence states in films. The Gd 3d doublet was shown with energy difference equal Δ = 32.7 eV. Gd concentration (at. %) reduced from 6 and 7% in GNO and GTO powder precursors to 3 and 2% in films, respectively. Experimental value of Gd/Nb/O and Gd/Ta/O ratio was determined 0.5:1:8.3 and 0.3:1:6.3. Luminescent properties of GNO and GTO films were measured for the first time. Excitation spectra of the GNO and GTO presented broad peaks at 257 and 263 nm, that were designated to the charge transfer bands (CTB) resulting to the O2− → Nb5+ or O2− → Ta5+ transition. Emission spectra reflected strait peak at 312 nm ascribed to the Gd3+ 4f–4f intraconfigurational transition 8S7/2 → 6P7/2 and wide peak at about 360 nm related to the CTB transition of NbO43− and TaO43− groups. Time-resolved spectrum was described by two components at 315 and 311 nm assigned 6P7/2 → 8S7/2 and 6P5/2 → 8S7/2 transition, respectively in both films destined such as sensors and display devices.

Prepared powder polyhydroxybutyrate – chitosan - calcium phosphate composite system with 10 wt % of biopolymer component can be utilized as biocement which is characterized by the prolonged setting time and achieves wash out resistance after 5 minutes of setting. The origin powder tetracalcium phosphate/nanomonetite agglomerates were coated with the thin layer of biopolymer which decelerates both the transformation rate of calcium phosphates and hardening process of composites. The porosity of hardened composite was around 62% and the compressive strength (8 MPa) was close to trabecular bone. No cytotoxicity of composite resulted from live/dead staining of osteoblasts cultured on substrates.

Lanthanide niobate LnNbO4 (LnNO) and tantalate LnTaO4 (LnTO) thin films (~100 nm) were prepared by sol-gel/spin-coating process on PZT/Al2O3 substrates and annealing at 1000 °C (Ln = Nd, Sm, Eu and Gd). The LnNO (NNO, SNO, ENO and GNO) and LnTO (NTO, STO, ETO and GTO) precursors of films were synthesized using Nb or Ta tartrate complexes. The different phase transformations were identified in LnNO or LnTO precursors from fluorite T′-structure via tetragonal T-LnNbO4 (NNO, SNO and GNO) or T-EuNb5O14 and T-NdTaO4, T-SmTa7O19, hexagonal H-EuTa7O19 and cubic C-GdTa7O19 to monoclinic M-LnNbO4 or M′-LnTaO4 during annealing at 700–1200 °C. The XRD results of LnNO or LnTO films confirmed the coexistence of monoclinic LnNbO4 or LnTaO4 phase in addition to the tetragonal as main phase at 1000 °C. In STO film, the single monoclinic M′-SmTaO4 phase was revealed. The surface morphology and topography of thin films were investigated by the SEM and AFM analysis. STO film was smoother with roughness of 3.23 nm in comparison with SNO (6.35 nm). Effect of lanthanides can contribute to the formation different polymorphs of these films for the application to environmental electrolytic thin film devices. Keywords: Lanthanides, Sol-gel, Thin films, Phase transformation, Microstructures

In this work, properties of perovskite lanthanum niobate La1/3NbO3 (LN) and tantalate La1/3TaO3 (LT) transparent thin films (∼200 nm thickness) prepared by chemical solution deposition on Pt/SiO2/Si substrates were described. The precursors and films were analyzed using FTIR and XPS spectra, XRD and SEM imaging. The both films after annealing at 1100 °C contained perovskite phase with a small fraction of pyrochlore LaNb5O14 (in LN). The heterogeneous microstructure of LN film was composed from spherical or needle-like particles and homogeneous LT film that resulted in significant changes of their mechanical properties. The elastic modulus and hardness of these films were characterized for the first time by conventional and continuous stiffness (CSM) nanoindentation. The LT film modulus (E) and hardness (H) were higher (∼105.7 and 5.3 GPa) than LN (∼91.5 and 3.8 GPa). The effect of microstructure on mechanical properties is significant. In addition, the average Derjaguin–Muller–Toporov (DMT)-based elastic modulus of LN film surface were estimated ∼50 GPa using AFM PeakForce QNM elastic mapping. The findings presented here can contribute to the fabrication of LN and LT films for the application to electrolytic thin film devices.

Tetracalcium phosphate/nanomonetite (TTCPMH) cement composites with 7.5 and 15 wt% addition of melt-derived 45S5 bioactive glass were prepared by mechanical homogenization of powder components and 2% NaH 2 PO 4 solution was used as a hardening liquid. The properties of composites with the acidic (Ca/P ratio equal 1.5) or basic (Ca/P ratio equal 1.67) TTCPMH component were compared. Addition of glass component caused rapid rise in pH of composites up to 10. In microstructure of basic cement composite, the large bioglass particles weakly bounded to surrounding cement matrix were found contrary to a more compact microstructure of acidic cement composites with the high number of spherical silica particles. Both the significant refinement of hydroxyapatite particles and the change to needle-like morphology with rise in the content of bioglass were identified in hydroxyapatite coatings created during soaking of composites in phosphate buffered saline. In acidic cement mixtures, the increase of compressive strength with an amount of bioglass was found whereas the opposite tendency was revealed in the case of basic cement mixtures. The higher concentrations of ions were verified in solutions after immersion of acidic cement composites. The severe cytotoxicity of extracts and composite cement substrates containing 15 wt% of bioglass demonstrated adverse effects of both the ionic concentrations and unappropriate surface texture on proliferation of mesenchymal stem cells. The enhanced ALP activities of cells cultured on composite cements confirmed the positive effect of bioactive glass addition on differentiation of mesenchymal stem cells.

Soft magnetic composite materials were prepared by powder metallurgy technology. The composition of the new family of the materials was based on Permalloy type of ferromagnetic particles covered by $$\hbox {Ni}_{0.2}\hbox {Zn}_{0.8}\hbox {Fe}_{2}\hbox {O}_{4}$$ nanoparticles. The spinel ferrite was prepared by electrospinning technology for achieving high-quality nanoparticles. A small amount of organic additives was included in final samples. The influence of magnetic ferrite dielectric coating on the magnetic properties of prepared composites was studied. The relatively high electrical resistivity leads to the real part of complex permeability up to 52 with stability up to high frequencies of about 1 MHz. SEM and TEM analyses were employed for composite characterization. The preparation of samples for magnetic force microscopic analysis is outlined in detail. The visualization of magnetic domain structure was done in order to understand the material behaviour of magnetic materials.

Magnesium containing calcium silicates have recently shown that they are promising materials for various biomedical application with potential use in the form of bulk ceramic, composite scaffold or coatings on metallic substrates. A novel akermanite (AK; Ca2MgSi2O7)/dicalcium phosphate dihydrate (DCPD, CaHPO4. H2O) cement mixture was tested in this work in order to produce an alternative AK/DCPD biocement for orthopedic applications. For comparison, we have prepared two cements mixed with 2.5 wt% NaH2PO4 solution (labeled as NaH2PO4 cement) and with the solution composed of organic 2.5 wt% citric acid a 2.5 wt% trisodium citrate (citrate cement) respectively. The results demonstrated only a partial dissolution of AK, regardless of the type of liquid used. On the other hand, the DCPD was completely hydrolyzed much faster in the citrate cement. The final hydration product was an amorhous quarternary phase of CaO-MgO-SiO2-P2O5 composition with the remaining unreacted akermanite embeded in the cement matrix. The highest early compressive strength was observed in the citrate cement (33 MPa), but much lower value was measured in NaH2PO4 cement (7 MPa) after 1 d setting. Different cell responses have been observed when the cells were cultured on the surfaces of cement substrates. While the NaH2PO4 cement demonstrated high proliferation activity of osteoblast, the citrate cement showed strong cytotoxic cell response, probably as a result of higher concentration of citrates on the cement surface, which can negatively affect the attachment and proliferation of osteoblastic cells.

Biopolymer composites allow the creation of an optimal environment for the regeneration of chondral and osteochondral defects of articular cartilage, where natural regeneration potential is limited. In this experimental study, we used the sheep animal model for the creation of knee cartilage defects. In the medial part of the trochlea and on the medial condyle of the femur, we created artificial defects (6 × 3 mm2) with microfractures. In four experimental sheep, both defects were subsequently filled with the porous acellular polyhydroxybutyrate/chitosan (PHB/CHIT)-based implant. Two sheep had untreated defects. We evaluated the quality of the newly formed tissue in the femoral trochlea defect site using imaging (X-ray, Computer Tomography (CT), Magnetic Resonance Imaging (MRI)), macroscopic, and histological methods. Macroscopically, the surface of the treated regenerate corresponded to the niveau of the surrounding cartilage. X-ray examination 6 months after the implantation confirmed the restoration of the contour in the subchondral calcified layer and the advanced rate of bone tissue integration. The CT scan revealed a low regenerative potential in the bone zone of the defect compared to the cartilage zone. The percentage change in cartilage density at the defect site was not significantly different to the reference area (0.06–6.4%). MRI examination revealed that the healing osteochondral defect was comparable to the intact cartilage signal on the surface of the defect. Hyaline-like cartilage was observed in most of the treated animals, except for one, where the defect was repaired with fibrocartilage. Thus, the acellular, chitosan-based biomaterial is a promising biopolymer composite for the treatment of chondral and osteochondral defects of traumatic character. It has potential for further clinical testing in the orthopedic field, primarily with the combination of supporting factors.

The composite cement mixtures were prepared by mixing brushite (B) with, the amorphous hydrated calcium silicate phosphate (CSPH) or annealed calcium silicate phosphate (CSP composed of Si-saturated hydroxyapatite, wollastonite and silica) phases and water as liquid component. The contents of the silicate-phosphate phase in composites were 10.30 and 50 wt%. The significant effect of both the Ca/P ratio and different solubility of calcium silicate phosphate component in starting cement systems on setting time and phase composition of the final composite cements was demonstrated. The compressive strength of the set cements increased with the filler addition and the highest value (~ 48 MPa) exhibited the 50CSP/B cement composite. The final setting times of the composite cements decreased with the CSPH addition from about 25 to 17 min in 50CSHP/B and setting time of CSP/B composites was around 30 min. The higher content of silica in cements caused the precipitation of fine hydroxyapatite particles in the form of nanoneedles or thin plates perpendicularly oriented to sample surface. The analysis of in vitro cement cytotoxicity demonstrated the strong reduction in cytotoxicity of 10CSPH/B composite with time of cultivation (a low cytotoxicity after 9 days of culture) contrary to cements with higher calcium silicate-phosphate content. These results were attributed to the different surface topography of composite substrates and possible stimulation of cell proliferation by the slow continuously release of ions from 10CSPH/B cement.

Perovskite lanthanum niobate La 1/3 NbO 3 (LN), tantalate La 1/3 TaO 3 (LT) and La 1/3 Nb 0.8 Ta 0.2 O 3 (LNT) thin films (~150 nm thickness) were prepared for the first time by sol–gel/spin-coating process on Pt/SiO 2 /Si substrates and annealing at 1100 °C. The novel precursors of films were synthesized using Nb- or Ta-tartrate complexes. XRD analyses confirmed that the LT possessed a single perovskite tetragonal La 0.33 TaO 3 phase, while LN or LNT films contained perovskite orthorhombic La 1/3 NbO 3 or tetragonal La 1/3 TaO 3 and traces of secondary pyrochlore LaNb 5 O 14 . The spherical and needle-like particles in heterogeneous microstructure of LN and LNT films and presence homogeneous transparent clusters of spherical nanoparticles in LT were observed.

Although several new implants have been developed using animal studies for the treatment of osteochondral and cartilage defects, there is a lack of information on the possible metabolic and biochemical reactions of the body to the implantation of biomaterials and cartilage reconstruction. Therefore, this study was aimed at evaluating the serum protein pattern and the alterations in the concentrations of selected acute phase proteins in five clinically healthy female sheep before and after the reconstruction of experimentally induced articular cartilage defects using polyhydroxybutyrate/chitosan based biopolymer material. The concentrations of total serum proteins (TSP), protein fractions, and selected acute phase proteins&mdash, serum amyloid A (SAA), haptoglobin (Hp), and C-reactive protein (CRP)&mdash, were measured before and on days seven, 14, and 30 after the surgical intervention. The TSP concentrations showed no marked differences during the evaluated period. Albumin values decreased on day seven and day 14 after surgery. In the concentrations of &alpha, 1-, &alpha, 2-, &beta, and &gamma, 2-globulins, a gradual significant increase was observed during the postoperative period (p &lt, 0.05). The &gamma, 1-globulins decreased slightly seven days after surgery. The concentrations of SAA, Hp, and CRP increased significantly after the surgical intervention with a subsequent decrease on day 30. Presented results suggest marked alterations in the serum protein pattern after surgical intervention.

The in vitro cytotoxicity of both the multiwalled carbon nanotubes (MWCNT) in suspension with culture medium and the tetracalcium phosphate/monetite cement with addition of 0.8 wt% of MWCNTs on fibroblasts and osteoblasts were studied. The cytotoxicity was evaluated by MTS test (formazan) and live/dead staining. No cytotoxicity of MWCNT extract was measured contrary to about 60% reduction in proliferation of fibroblasts in MWCNT suspension as compared with negative control. The several contact cytotoxicity of MWCNT composite cement surfaces on seeded cells was demonstrated by MTS test and live/dead staining of damaged fibroblasts and dead osteoblasts after 72 h of culture. The detailed microstructure analysis showed a significant refinement of the surface texture due to the formation of thin needle-like hydroxyapatite particles on MWCNTs and this effect could be responsible for cytotoxicity of composites.

Soft magnetic core–shell particles were designed by coating FeSi and permalloy powders with ferrite nanoparticles. The permalloy-type powder particles were prepared by mechanical alloying process of 80 wt% of Ni, 14.7 wt% of Fe, 4.4 wt% of Mo, 0.5 wt% of Mn and 0.3 wt% Si. NiFe2O4 cuboidal nanoparticles were synthesized by the chemical precipitation of hydroxides by alkaline treatment of the dissolved metal in aqueous chloride solution and the same process was used for a deposition of NiFe2O4 nanoparticles on both substrates. The average size of NiFe2O4 nanoparticles, crystallinity and spinel structure were determined by TEM and XRD techniques. The deposited coating was created in a bilayer form. The composition of individual layer was analyzed by XRD and TEM using 100-nm lamella extracted from the coating by focused ion beam. The chemical composition of individual layers was analyzed by EDX analysis. The specific electric resistivity measurement has confirmed a good insulating character of the designed bilayer coating, whereas the prepared core–shell powders and relevant green compacts belong to soft magnetic materials.

Soft magnetic composites (SMCs) were prepared from three different ferromagnetic powder particles: iron powder ASC 100.29, spherical FeSi particles and vitroperm (Fe73Cu1Nb3Si16B7) flakes. Two types of hybrid organic–inorganic phenolic resins modified with either silica nanoparticles or boron were used to design a thin insulating layer perfectly covering the ferromagnetic particles. Fourier transform infrared (FTIR) spectrometry confirmed an incorporation of silica or boron into the polymer matrix, which manifested itself through an improved thermal stability of the hybrid resins verified by thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The core-shell particles prepared from the ferromagnetic powder particles and the modified hybrid resins were further compacted to the cylindrical and toroidal shapes for the mechanical, electrical and magnetic testing. A uniform distribution of the resin between the ferromagnetic particles was evidenced by scanning electron microscope (SEM) analysis, which was also reflected in a rather high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in SMC consisting of the iron powder and phenolic resin modified with boron. The coercive fields of the prepared samples were comparable with the commercial SMCs.

Bone cements based on magnesium phosphates such as newberyite (N; MgHPO4.3H2O) have been shown as potential bone substitutes due to their biocompatibility, biodegradability and ability to support osteoblast differentiation and proliferation. Newberyite can hydrolyze to hydrated magnesium phosphate compounds (e.g. bobierite (Mg3(PO4)2.8H2O)) at alkaline conditions. In this study, 25 and 50 wt% of crystalline β -wollastonite (woll; CaSiO3) was admixed to newberyite powder in order to both enhance the acid-base hydrolysis of newberyite and to produce a functional bone cement. The setting process of wollastonite/newberyite cement mixtures started with the hydrolysis of the wollastonite with further transformation of newberyite into bobierite and the formation of magnesium silicate phase. The results demonstrated that 25 wollastonite/newberyite and 50 wollastonite/newberyite cement pastes at optimal powder/liquid ratios had final setting times of ∼34 and 25 min and compressive strength values of 18 and 32 MPa after seven days setting, respectively. The tests of cytotoxicity of cement extracts on osteoblastic cells and contact cytotoxicity of the cement substrates showed different results. The osteoblasts cultured in cement extracts readily proliferated which confirmed the non-cytotoxic concentration of ions released from both cements. On the other hand, a strong cytotoxic character of 25 wollastonite/newberyite sample surface in contrary to high (∼80%) proliferation activity of cells on the 50 wollastonite/newberyite cement substrate was observed. The differences in cell proliferation activity was attributed to different surface topographies of cement substrates, where needle-like precipitated microcrystals of magnesium phosphate phase (in 25 wollastonite/newberyite cement) prevented the adhesion and proliferation of osteoblasts contrary to the smoother surface covered by extremely fine nanoparticles in the 50 wollastonite/newberyite cement.

International audience; The function and integrity of the nervous system require interactive exchanges among neurons and glial cells. Exosomes and other extracellular vesicles (EVs) are emerging as a key mediator of intercellular communication, capable of transferring nucleic acids, proteins and lipids influencing numerous functional and pathological aspects of both donor and recipient cells. The immune response mediated by microglia-derived exosomes is most prominently involved in the spread of neuroinflammation, neurodegenerative disorders, and brain cancer. Therefore, in the present study we describe a reproducible and highly efficient method for yielding purified primary microglia cells, followed by exosome isolation and their characterization. An in vitro biological assay demonstrates that microglia-derived exosomes tested on a 3D spheroid glioma culture were able to inhibit tumor invasion in time course. These results evidence that brain microglia-derived exosomes could be used as nanotherapeutic agents against glioma cells.

Objectives To investigate the tubule occlusion and remineralization potential of a novel toothpaste with active tetracalcium phosphate/monetite mixtures under de/remineralization cycling. Methods Dentin de/remineralization cycling protocol consisted of demineralization in 1% citric acid at pH 4.6 with following remineralization with toothpastes and soaking in artificial saliva. Effectiveness of toothpastes to promote remineralization was evaluated by measurement of microhardness recovery, analysis of surface roughness, thickness of coating and scanning electron microscopy. Results The novel tetracalcium phosphate/monetite dentifrice had comparable remineralization potential as commercial calcium silicate/phosphate (SENSODYNE®) and magnesium aluminum silicate (Colgate®) toothpastes and significantly higher than control saliva (p Conclusions The new fluoride toothpaste formulation with bioactive tetracalcium phosphate/monetite calcium phosphate mixture effectively occluded dentin tubules and showed good dentin remineralization potential under de/remineralization cycling. It could replace professional powder preparation based on this mixture. It was demonstrated that prepared dentifrice had comparable properties with commercial fluoride calcium silicate/phosphate or magnesium aluminum silicate dentifrices.

The tetracalcium phosphate–monetite cement mixture was prepared by reaction milling of tetracalcium phosphate with the orthophosphoric acid ethanol solution. The presence of nanomonetite phase caused significant lowering of the pH value in cement paste during hardening. The agglomerates of nanomonetite phase homogeneously distributed in powder cement mixture were observed by TEM. The compressive strength and setting times of cement were 35 MPa and 4–9 min respectively.

Self-setting simple calcium silicate/brushite (B) biocements with various Ca/P ratios were prepared by mutual mixing of both monocalcium silicate hydrate (CSH) or ?-wollastonite (woll) powders with B and the addition of 2 wt% NaH2PO4 solution as a hardening liquid. The phase composition of the final composites and the texture of the surface calcium phosphate/silica layer were controlled by the starting Ca/P ratio in composites and the pH during setting. It was verified that the presence of continuous bone-like calcium phosphate coating on the surface of the samples was not essential for in vitro osteoblast proliferation. The nanocrystalline calcium deficient hydroxyapatite and amorphous silica were found as the main setting products in composite mixtures with a Ca/P ratio close to the region of the formation of deficient hydroxyapatite-like calcium phosphates. No CSH phase with a lower Ca/Si ratio was identified after transformation. The results confirmed a small effect of the monocalcium silicate addition on the compressive strength (CS) of cements up to 30 wt% (around 20?25?MPa) and a significant rise of the value in 50 woll/B cement (65?MPa). The final setting times of the cement composites varied between 5 and 43?min depending on the P/L ratio and the type of monocalcium silicate phase in the cement mixture. 10CSH/B and 50 woll/B cements with different textures but free of both the needle-like and perpendicularly-oriented hydroxyapatite particles on the surface of the samples had low cytotoxicity.

Polyhydroxybutyrate/chitosan/calcium phosphate composites are interesting biomaterials for utilization in regenerative medicine and they may by applied in reconstruction of deeper subchondral defects. Insufficient informations were found in recent papers about the influence of lysozyme degradation of chitosan in calcium phosphate/chitosan based composites on in vitro cytotoxicity and proliferation activity of osteoblasts. The effect of enzymatic chitosan degradation on osteoblasts proliferation was studied on composite films in which the porosity of origin 3D scaffolds was eliminated and the surface texture was modified. The significantly enhanced proliferation activity with faster population growth of osteoblasts were found on enzymatically degraded biopolymer composite films with α-tricalcium phosphate and nanohydroxyapatite. No cytotoxicity of composite films prepared from lysozyme degraded scaffolds containing a large fraction of low molecular weight chitosans (LMWC), was revealed after 10 days of cultivation. Contrary to above in the higher cytotoxicity origin untreated nanohydroxyapatite films and porous composite scaffolds. The results showed that the synergistic effect of surface distribution, morphology of nanohydroxyapatite particles, microtopography and the presence of LMWC due to chitosan degradation in composite films were responsible for compensation of the cytotoxicity of nanohydroxyapatite composite films or porous composite scaffolds.

The octacalcium phosphate–poly(3-hydroxybutyrate) (OCP–PHB) thin film powder composites were prepared by the precipitation of PHB from OCP–PHB from chloroform suspension. The morphology of powder OCP–PHB composite and microstructure of composite pellets were observed by scanning electron microscopy. The presence of PHB thin film on OCP particles and the formation of new calcium phosphate phase after soaking of compact in simulated body fluid (SBF) at 37 °C for 2 weeks were verified. Phase composition was analysed by X-ray diffraction analysis and IR spectroscopy. The composite pellets were resistant to disintegration after immersion into SBF and the compressive strength of composite was around 6 MPa.

Nanocrystalline hydroxyapatites were prepared by the precipitation method using a water soluble Ca 2+ organic compounds and (NH 4 ) 2 HPO 4 . The fine nanohydroxyapatites had spherical, needle-like or mixed morphology and specific areas around 150 m 2 /g. The nanocrystalline powders differed by thermal stability and they were transformed to bi- or three-phasic systems with hydroxyapatite, βTCP and αTCP phases after annealing at 1000 °C.