Search

The novel material class of high entropy oxides with their unique and unexpected physicochemical properties is a candidate for energy applications. Herein, it is reported for the first time about the physico‐ and (photo‐) electrochemical properties of ordered mesoporous (CoNiCuZnMg)Fe2O4 thin films synthesized by a soft‐templating and dip‐coating approach. The A‐site high entropy ferrites (HEF) are composed of periodically ordered mesopores building a highly accessible inorganic nanoarchitecture with large specific surface areas. The mesoporous spinel HEF thin films are found to be phase‐pure and crack‐free on the meso‐ and macroscale. The formation of the spinel structure hosting six distinct cations is verified by X‐ray‐based characterization techniques. Photoelectron spectroscopy gives insight into the chemical state of the implemented transition metals supporting the structural characterization data. Applied as photoanode for photoelectrochemical water splitting, the HEFs are photostable over several hours but show only low photoconductivity owing to fast surface recombination, as evidenced by intensity‐modulated photocurrent spectroscopy. When applied as oxygen evolution reaction electrocatalyst, the HEF thin films possess overpotentials of 420 mV at 10 mA cm−2 in 1 m KOH. The results imply that the increase of the compositional disorder enhances the electronic transport properties, which are beneficial for both energy applications.

Lithium argyrodite-type electrolytes are regarded as promising electrolytes due to their high ionic conductivity and good processability. Chemical modifications to increase ionic conductivity have already been demonstrated, but the influence of these modifications on interfacial stability remains so far unknown. In this work, we study Li 6 PS 5 Cl and Li 5.5 PS 4.5 Cl 1.5 to investigate the influence of halogenation on the electrochemical decomposition of the solid electrolyte and the chemical degradation mechanism at the cathode interface in depth. Electrochemical measurements, gas analysis and time-of-flight secondary ion mass spectrometry indicate that the Li 5.5 PS 4.5 Cl 1.5 shows pronounced electrochemical decomposition at lower potentials. The chemical reaction at higher voltages leads to more gaseous degradation products, but a lower fraction of solid oxygenated phosphorous and sulfur species. This in turn leads to a decreased interfacial resistance and thus a higher cell performance.

Mass spectrometric imaging approach for ex vivo monitoring of drug transport in bone sections. Cryo-ToF-SIMS depth profiling and high-resolution imaging as well as OrbiSIMS analysis revealed inhomogeneous Sr2+ transport in rat bone marrow.

The soft nature of cluster-induced desorption/ionization allows for unambiguous identification of highlighter inks and the discrimination of different degradation processes by means of mass spectrometry.

All-solid-state batteries are intensively investigated, although their performance is not yet satisfactory for large-scale applications. In this context, the combination of Li10GeP2S12 solid electrolyte and LiNi1-x-yCoxMnyO2 positive electrode active materials is considered promising despite the yet unsatisfactory battery performance induced by the thermodynamically unstable electrode|electrolyte interface. Here, we report electrochemical and spectrometric studies to monitor the interface evolution during cycling and understand the reactivity and degradation kinetics. We found that the Wagner-type model for diffusion-controlled reactions describes the degradation kinetics very well, suggesting that electronic transport limits the growth of the degradation layer formed at the electrode|electrolyte interface. Furthermore, we demonstrate that the rate of interfacial degradation increases with the state of charge and the presence of two oxidation mechanisms at medium (3.7 V vs. Li+/Li < E vs. Li+/Li) and high (E ≥ 4.2 V vs. Li+/Li) potentials. A high state of charge (>80%) triggers the structural instability and oxygen release at the positive electrode and leads to more severe degradation.

For driving the (photo-) electrocatalytic water splitting reaction both efficient and photostable absorber materials and electrocatalysts are needed in order to make the technology economically competitive. The novel material class of high entropy oxides with their unique and unexpected physicochemical properties is a potential candidate for energy applications. Herein, we report for the first time about the physico- and (photo-) electrochemical properties of ordered mesoporous (CoNiCuZnMg)Fe2O4 thin films synthesized by a soft-templating and dip-coating approach. The high entropy ferrites (HEF) are composed of 15 ‒ 18 nm sized and periodically ordered mesopores building a highly accessible inorganic nanoarchitecture with specific surface areas up to 170 m2/g. The mesoporous HEF thin films crystallize in the cubic spinel structure and were found to be crack-free on the meso- and macroscale. The formation of the spinel structure hosting six distinct cations was verified by means of gracing incidence X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and transmission electron microscopy accompanied with energy dispersive X-ray spectroscopy. Photoelectron spectroscopy gave insight into chemical state of the implemented transition metals supporting the structural characterization data. Analyzed as photoanode for photoelectrochemical water splitting, the HEFs showed only low photoconductivity owing to fast surface recombination as suggested by intensity-modulated photocurrent spectroscopy. When applied as oxygen evolution reaction electrocatalyst, the HEF thin films possess overpotentials of 420 mV vs. RHE at 10 mA/cm2 in 1 M KOH. The results imply that the increase of the configurational disorder within the spinel structure enhances the electronic transport properties. The evaluation of the energy band alignment by Mott-Schottky analysis allows for an estimation which redox reactions can be driven, showing that the materials are theoretically capable of promoting overall water splitting.

Strontium (Sr

Large-scale industrial application of all-solid-state-batteries (ASSBs) is currently hindered by numerous problems. Regarding thiophosphate-based ASSBs, interfacial reactions with the solid electro...

The introduction of dislocations is a recently proposed strategy to tailor the functional and especially the electrical properties of ceramics. While several works confirm a clear impact of dislocations on electrical conductivity, some studies raise concern in particular when expanding to dislocation arrangements beyond a geometrically tractable bicrystal interface. Moreover, the lack of a complete classification on pertinent dislocation characteristics complicates a systematic discussion and hampers the design of dislocation-modified electrical conductivity. We proceed by mechanically introducing dislocations with three different mesoscopic structures into the model material single-crystal SrTiO3 and extensively characterizing them from both a mechanical as well as an electrical perspective. As a final result, a deconvolution of mesoscopic structure, core structure, and space charge enables us to obtain the complete picture of the effect of dislocations on functional properties, focusing here on electric properties.

In osteoporosis research, strontium ions (SrFor this comparatively fast diffusion (FD) experiment, a specific experimental protocol of ToF-SIMS depth profiling under cryogenic conditions was developed. The validity of our experimental approach is proven by a time-dependent experimental series. Furthermore, 2D and 3D mass spectrometric imaging analysis was used to study SrDetailed 2D and 3D mass spectrometric imaging analysis revealed that SrWe were able to show that cryo-ToF-SIMS is a useful tool for the characterization of rapid diffusion in water-containing highly viscous media. To the best of our knowledge, this is the first reported experimental approach for the investigation of the distribution of low concentrated therapeutic agents in bone marrow. Overall, our results provide important insights about Sr

Aiming at the generation of a high strontium-containing degradable bone substitute, the exchange of calcium with strontium in gelatin-modified brushite was investigated. The ion substitution showed two mineral groups, the high-calcium containing minerals with a maximum measured molar Ca/Sr ratio of 80%/20% (mass ratio 63%/37%) and the high-strontium containing ones with a maximum measured molar Ca/Sr ratio of 21%/79% (mass ratio 10%/90%). In contrast to the high-strontium mineral phases, a high mass loss was observed for the calcium-based minerals during incubation in cell culture medium (alpha-MEM), but also an increase in strength owing to dissolution and re-precipitation. This resulted for the former in a decrease of cation concentration (Ca + Sr) in the medium, while the pH value decreased and the phosphate ion concentration rose significantly. The latter group of materials, the high-strontium containing ones, showed only a moderate change in mass and a decrease in strength, but the Ca + Sr concentration remained permanently above the initial calcium concentration in the medium. This might be advantageous for a future planned application by supporting bone regeneration on the cellular level.

On the way to a large-scale industrial application of all-solid-state batteries (ASSBs) it is necessary to overcome a number of challenges. An important task is to maximize the utilization of activ...

ACS catalysis 9(7), 6530 - 6539 (2019). doi:10.1021/acscatal.9b01402, Sophisticated $\mathrm{IrO_{2}(110)}$-based model electrodes are prepared by deposition of a 10 nm thick single-crystalline $\mathrm{IrO_{2}(110)}$ layer supported on a structure-directing $\mathrm{IrO_{2}(110)-RuO_{2}(110)/Ru(0001)}$ template, exposing a regular array of mesoscopic rooflike structures. With this model electrode together with the dedicated in situ synchrotron based techniques (SXRD, XRR) and ex situ characterization techniques (SEM, ToF-SIMS, XPS), the corrosion process of $\mathrm{IrO_{2}(110)}$ in an acidic environment (pH 0.4) is studied on different length scales. Potential-induced pitting corrosion starts at 1.48 V vs SHE and is initiated at so-called surface grain boundaries, where three rotational domains of $\mathrm{IrO_{2}(110)}$ meet. The most surprising result is, however, that even when the electrode potential is increased to 1.94 V vs SHE 60–70% of the $\mathrm{IrO_{2}}$ film still stays intact down to the mesoscale and atomic scale and no uniform thinning of the $\mathrm{IrO_{2}(110)}$ layer is encountered. Neither flat$\mathrm{IrO_{2}(110)}$ terraces nor single steps are attacked. Ultrathin single-crystalline $\mathrm{IrO_{2}(110)}$ layers seem to be much more stable to anodic corrosion than hitherto expected., Published by ACS, Washington, DC

All-solid-state lithium-ion batteries (ASSBs) are expected to represent a future alternative compared to conventional lithium-ion batteries with liquid electrolytes (LIBs). The excellent performanc...

The introduction of dislocations is a recently proposed strategy to tailor the functional and especially the electrical properties of ceramics. While several works confirm a clear impact of dislocations on electrical conductivity, some studies raise concern in particular when expanding to dislocation arrangements beyond a geometrically tractable bicrystal interface. Moreover, the lack of a complete classification on pertinent dislocation characteristics complicates a systematic discussion and hampers the design of dislocation-modified electrical conductivity. We proceed by mechanically introducing dislocations with three different mesoscopic structures into the model material single-crystal SrTiO

Primary-ion-induced fragmentation in organic molecules can strongly influence the results in secondary-ion mass spectrometry (SIMS) of organic and biomolecular samples. In order to characterize this ion-induced fragmentation, oligopeptide samples irradiated in SIMS experiments were investigated by means of desorption/ionization induced by neutral SO2 clusters (DINeC). The latter is a nondestructive desorption method for mass spectrometry of biomolecules, which gives direct access to the fragments induced in the sample. Comparison of TOF-SIMS and DINeC mass spectra revealed qualitative differences between the fragments, which remain in the sample and the fragments sputtered during ion bombardment. The fragmentation strength and its spatial distribution were found to be quantitatively different for Bi1+, Bi3+, and Ar1000+ primary ions, leading to different distributions of the degree of fragmentation in the samples as directly measured by means of DINeC depth profiles.

The present work focuses on the application of time-of-flight secondary ion mass spectrometry (ToF-SIMS) in osteoporotic bone research. In order to demonstrate the benefit, the authors present concrete application examples of ToF-SIMS in three different areas of bone research. ToF-SIMS as a mass spectrometric imaging technique allows simultaneous visualization of mineralized and nonmineralized bone tissue as well as implanted biomaterials and bone implant interphases. In the first example, the authors show that it is possible to study the incorporation and distribution of different components released from bone filler materials into bone with a single mass spectrometric measurement. This not only enables imaging of nonstained bone cross sections but also provides further insights beyond histologically obtained information. Furthermore, they successfully identified several mass fragments as markers for newly formed cartilage tissue and growth joint in bone. Different modes of ToF-SIMS as well as different SIMS instruments (IONTOF's TOF.SIMS 5 and M6 Hybrid SIMS, Ionoptika's J105) were used to identify these mass signals and highlight the high versatility of this method. In the third part, bone structure of cortical rat bone was investigated from bone sections embedded in technovit (polymethyl methacrylate, PMMA) and compared to cryosections. In cortical bone, they were able to image different morphological features, e.g., concentric arrangement of collagen fibers in so-called osteons as well as Haversian canals and osteocytes. In summary, the study provides examples of application and shows the strength of ToF-SIMS as a promising analytical method in the field of osteoporotic bone research.

Desorption/ionization induced by neutral clusters (DINeC) is used as an ultrasoft desorption/ionization method for the analysis of fragile biomolecules by means of mass spectrometry (MS). As a test molecule, the glycopeptide vancomycin was measured with DINeC-MS, and resulting mass spectra were compared to the results obtained with electrospray ionization (ESI), matrix assisted laser desorption ionization, and time-of-flight secondary ion MS. Of the desorption-based techniques, DINeC spectra show the lowest abundance of fragments comparable to ESI spectra. The soft desorption nature of DINeC was further demonstrated when applied to MS analysis of teicoplanin.

A method is described for high-resolution label-free molecular imaging of human bone tissue. To preserve the lipid content and the heterogeneous structure of osseous tissue, 4 μm thick human bone sections were prepared via cryoembedding and tape-assisted cryosectioning, circumventing the application of organic solvents and a decalcification step. A protocol for comparative mass spectrometry imaging (MSI) on the same section was established for initial analysis with time-of-flight secondary ion mass spectrometry (TOF-SIMS) at a lateral resolution of 10 μm to500 nm, followed by atmospheric pressure scanning microprobe matrix-assisted laser desorption/ionization (AP-SMALDI) Orbitrap MSI at a lateral resolution of 10 μm. This procedure ultimately enabled MSI of lipids, providing the lateral localization of major lipid classes such as glycero-, glycerophospho-, and sphingolipids. Additionally, the applicability of the recently emerged Orbitrap-TOF-SIMS hybrid system was exemplarily examined and compared to the before-mentioned MSI methods.

Surface coating is a viable strategy for improving the cyclability of Li1+x(Ni1–y–zCoyMnz)1–xO2 (NCM) cathode active materials for lithium-ion battery cells. However, both gaining synthetic control over thickness and accurate characterization of the surface shell, which is typically only a few nm thick, are considerably challenging. Here, we report on a new molecular surface modification route for NCM622 (60% Ni) using organophosphates, specifically tris(4-nitrophenyl) phosphate (TNPP) and tris(trimethylsilyl) phosphate. The functionalized NCM622 was thoroughly characterized by state-of-the-art surface and bulk techniques, such as attenuated total reflection infrared spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS), to name a few. The comprehensive ToF-SIMS-based study comprised surface imaging, depth profiling, and three-dimensional visualization. In particular, tomography is a powerful tool to analyze the nature and morphology of thin coatings...

Low modulus Ti-45Nb is a promising new alloy for bone implant applications owing to its excellent biocompatibility combined with bone-adapted mechanical performance. The present work demonstrates the applicability of powder metallurgical processing, i.e. hot pressing (HP) and spark plasma sintering (SPS), for the compaction of gas-atomized alloy powder under preservation of the main β-phase. Additional milling of the gas-atomized powder leads to irregular shapes and is effective for a significant refinement of the β-phase grains but causes increased oxygen contents. The yield strength of nearly fully dense samples increased from ≈ 450 MPa for samples made from gas-atomized to ≈ 900 MPa for samples made from additionally milled powder while the Young's modulus remains low. Exemplarily, the production of macro-porous Ti-45Nb samples with 30% porosity by means of hot pressing with NaCl as space holder is demonstrated. At this porosity level Young's modulus values ≤ 5 GPa can be obtained. Also for macro-porous samples the use of additionally milled powder was beneficial for achieving increased strength values of ≈ 140 MPa. Mechanical performance data comparable to those of healthy spongy bone are obtained.

The modelling of electrode kinetics of solid oxide fuel cells is challenging, as the electrodes can change their composition and microstructure during operation at high temperature. Here we present results from in situ studies, applying time of flight secondary ion mass spectrometry (ToF-SIMS) to investigate compositional surface changes of lanthanum strontium manganate (LSM) model electrodes. Geometrically well-defined LSM electrodes with the composition La 0.74 Sr 0.17 Mn 1.01 O 2.9 were deposited as thin films on yttria stabilised zirconia (YSZ) single crystals by pulsed laser deposition. As counter electrode, a porous platinum electrode was applied on the backside of the solid electrolyte. The electrochemical polarisation experiments were carried out inside the ToF-SIMS analysis chamber at 430 °C, and the ToF-SIMS measurements were performed – in contrast to former work – for the first time during electrical polarisation at elevated temperatures. By applying either a cathodic or anodic potential to the LSM cathode, enrichment or depletion of the different metallic constituents on both, the LSM and free YSZ surface, and within the LSM near surface region, were observed. After polarisation, the system relaxes towards the thermodynamic equilibrium state. Already after the first heat treatment, diffusion of manganese and strontium from the LSM electrode onto the free YSZ surface is observed. The concomitant spreading of the three-phase boundary seems to be one reason for electrode activation after polarisation.

Dislocations have been recently introduced as a novel tool to tailor the conductivity of functional ceramics. However, tuning strategies suffer from poor insight into the structural complexity of dislocations and their networks. Here, we demonstrate that dislocations can be used to both enhance and reduce the overall conductivity in the same ceramic material. Accurate control of the arrangement of dislocations within the dislocation network enables tailoring TiO2 bulk samples to behave like being chemically modified either with an acceptor or donor dopant. Our approach combines ultra-high voltage electron microscopy, oxygen partial pressure, and temperature dependent electrical conductivity measurements combined with time-of-flight secondary ion mass spectrometry. This allows us to focus on mechanically tailored interaction of next neighbor dislocations and to differentiate between percolating conductive pathways and separated charge carrier zones. This seemingly simple approach purposefully tailors the conductivity of TiO2, opening new avenues to engineer functional ceramics beyond common chemical doping strategies.

Drug functionalization of biomaterials is a modern and popular approach in biomaterials research. Amongst others this concept is used for the functionalization of bone implants to locally stimulate the bone healing process. For example strontium ions (Sr2+) are administered in osteoporosis therapy to stimulate bone growth and have recently been integrated into bone cements. Based on results of different analytical experiments we developed a two-phase model for the transport of therapeutically active Sr2+-ions in bone in combination with Korsmeyer-Peppas kinetics for the Sr2+ release from bone cement. Data of cement dissolution experiments into water in combination with inductively coupled plasma mass spectrometry (ICP-MS) analysis account for dissolution kinetics following Noyes-Whitney rule. For dissolution in ??-MEM cell culture media the process is kinetically hindered and can be described by Korsmeyer-Peppas kinetics. Time of flight secondary ion mass spectrometry (ToF-SIMS) was used to determine the Sr2+ diffusion coefficient in healthy and osteoporotic trabecular rat bone. Therefore, bone sections were dipped in aqueous Sr2+-solution by one side and the Sr2+-profile was measured by classical SIMS depth profiling. The Sr2+ mobility can be described by a simple diffusion model and we obtained diffusion coefficients of (2.28??2.97)???10-12cm2/s for healthy and of (1.55??0.93)???10-10cm2/s for osteoporotic bone. This finding can be explained by a different bone nanostructure, which was observed by focused ion beam scanning electron microscopy (FIB-SEM) and transmission electron microscopy (TEM). Finally, the time and spatially resolved drug transport was calculated by finite element method for the femur of healthy and osteoporotic rats. The obtained results were compared to mass images that were obtained from sections of in vivo experiments by ToF-SIMS. The simulated data fits quite well to experimental results. The successfully applied model for the description of drug dispersion can help to reduce the number of animal experiments in the future.Copyright ?? 2017 Elsevier B.V. All rights reserved.

Lipids have numerous important functions in the human body, as they form the cells' plasma membranes and play a key role in many disease states, presumably also in osteoporosis. Here, the fatty acid composition of the outer plasma membranes of cells differentiated into the osteogenic and adipogenic direction is studied with surface-sensitive time-of-flight secondary ion mass spectrometry (ToF-SIMS). For data evaluation, principal component analysis (PCA) is applied. Human (bone-derived) mesenchymal stromal cells (hMSCs) from an osteoporotic donor and a control donor are compared to reveal differences in the fatty acid composition of the membranes. The chemical information is correlated to staining and real-time quantitative polymerase chain reaction (rt-qPCR) results to provide insight into the gene expression of several differentiation markers on the RNA level. Adipogenic differentiation of hMSCs from a non-osteoporotic donor correlates with increased relative intensities of all fatty acids under investigation. After osteogenic differentiation of non-osteoporotic cells, the relative mass signal intensities of unsaturated fatty acids such as oleic and linoleic acids are increased. However, the osteoporotic cells show increased levels of palmitic acid in the plasma membrane after exposure to osteogenic differentiation conditions, which correlates to an immature differentiation state relative to non-osteoporotic osteogenic cells. This immature differentiation state is confirmed by increased early osteogenic differentiation factor Runx2 on RNA level and by less calcium mineralization spots seen in von Kossa staining and ToF-SIMS images. Graphical abstract Time-of-flight secondary ion mass spectrometry is applied to analyze the fatty acid composition of the outer plasma membranes of cells differentiated into the adipogenic and osteogenic direction. Cells from an osteoporotic and a control donor are compared to reveal differences due to differentiation and disease stage of the cells.

Within thermoelectric generators, the chemical diffusion of a contact material into the active thermoelectric material is a potential cause for degradation, which has rarely been discussed in literature. Frequently, this degradation phenomenon leads to major problems in developing new modules and achieving long-term stability. In this study, copper as one of the standard contact materials and lead telluride as the state-of-the-art active material in the mid-temperature range are investigated. Chemical diffusion experiments of copper in lead telluride were carried out between 375 K and 795 K and the copper diffusion profiles were obtained by Secondary Ion Mass Spectrometry (SIMS). The evaluated chemical diffusion coefficient is lower than 10 −13 cm 2 /s in the respective temperature range.

Next-generation bone implants will be functionalized with drugs for stimulating bone growth. Modelling of drug release by such functionalized biomaterials and drug dispersion into bone can be used as predicting tool for biomaterials testing in future. Therefore, the determination of experimental parameters to describe and simulate drug release in bone is essential. Here, we focus on Sr 2+ transport and quantification in cortical rat bone. Sr 2+ dose-dependently stimulates bone-building osteoblasts and inhibits bone-resorbing osteoclasts. It should be preferentially applied in the case of bone fracture in the context of osteoporotic bone status. Transport properties of cortical rat bone were investigated by dipping experiments of bone sections in aqueous Sr 2+ solution followed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling. Data evaluation was carried out by fitting a suitable mathematical diffusion equation to the experimental data. An average diffusion coefficient of D = (1.68 ± 0.57) · 10 −13 cm 2 s −1 for healthy cortical bone was obtained. This value differed only slightly from the value of D = (4.30 ± 1.43) · 10 −13 cm 2 s −1 for osteoporotic cortical bone. Transmission electron microscopy investigations revealed a comparable nano- and ultrastructure for both types of bone status. Additionally, Sr 2+ -enriched mineralized collagen standards were prepared for ToF-SIMS quantification of Sr 2+ content. The obtained calibration curve was used for Sr 2+ quantification in cortical and trabecular bone in real bone sections. The results allow important insights regarding the Sr 2+ transport properties in healthy and osteoporotic bone and can ultimately be used to perform a simulation of drug release and mobility in bone.

The present study deals with the characterization of bone quality in a sheep model of postmenopausal osteoporosis. Sheep were sham operated ( n = 7), ovariectomized ( n = 6), ovariectomized and treated with deficient diet ( n = 8) or ovariectomized, treated with deficient diet and glucocorticoid injections ( n = 7). The focus of the study is on the microscopic properties at tissue level. Microscopic mechanical properties of osteoporotic bone were evaluated by a combination of biomechanical testing and mathematical modelling. Sample stiffness and strength were determined by compression tests and finite-element analysis of stress states was conducted. From this, an averaged microscopic Young’s modulus at tissue level was determined. Trabecular structure as well as mineral and collagen distribution in samples of sheep vertebrae were analysed by micro-computed tomography and time-of-flight secondary ion mass spectrometry. In the osteoporotic sheep model, a disturbed fibril structure in the triple treated group was observed, but bone loss only occurred in form of reduced trabecular number and thickness and cortical decline, while quality of the residual bone was preserved. The preserved bone tissue properties in the osteoporotic sheep model allowed for an estimation of bone strength which behaves similar to the human case.

The development of new and better implant materials adapted to osteoporotic bone is still urgently required. Therefore, osteoporotic muscarinic acetylcholine receptor M3 (M3 mAChR) knockout (KO) and corresponding wild type (WT) mice underwent osteotomy in the distal femoral metaphysis. Fracture gaps were filled with a pasty &alpha, tricalcium phosphate (&alpha, TCP)-based hydroxyapatite (HA)-forming bone cement containing mesoporous bioactive CaP-SiO2 glass particles (cement/MBG composite) with or without Brain-Derived Neurotrophic Factor (BDNF) and healing analyzed after 35 days. Histologically, bone formation was significantly increased in WT mice that received the BDNF-functionalized cement/MBG composite compared to control WT mice without BDNF. Cement/MBG composite without BDNF increased bone formation in M3 mAChR KO mice compared to equally treated WT mice. Mass spectrometric imaging showed that the BDNF-functionalized cement/MBG composite implanted in M3 mAChR KO mice was infiltrated by newly formed tissue. Leukocyte numbers were significantly lower in M3 mAChR KO mice treated with BDNF-functionalized cement/MBG composite compared to controls without BDNF. C-reactive protein (CRP) concentrations were significantly lower in M3 mAChR KO mice that received the cement/MBG composite without BDNF when compared to WT mice treated the same. Whereas alkaline phosphatase (ALP) concentrations in callus were significantly increased in M3 mAChR KO mice, ALP activity was significantly higher in WT mice. Due to a stronger effect of BDNF in non osteoporotic mice, higher BDNF concentrations might be needed for osteoporotic fracture healing. Nevertheless, the BDNF-functionalized cement/MBG composite promoted fracture healing in non osteoporotic bone.

Beta-type Ti-40Nb with very low Young's modulus is a promising alloy for long-term bone implant applications but surface states must be tailored for optimum osseointegration. Different anodization methods for surface oxidation were evaluated and oxide layers with characteristic morphologies were obtained. Anodization in fluoride-containing solutions generates oxide nanotubes with higher aspect ratio than those grown on CP2-Ti. The electrolyte composition has some influence on the oxide morphology. Plasma electrolytic oxidation in strongly alkaline solution yields a two-layer oxide structure with a thin compact inner layer and a much thicker outer layer with micropores and microchannels. Inductively coupled RF oxygen plasma anodization causes the formation of microstructured oxides on the Ti-40Nb surface. With increasing processing temperature a transition from random structured to patterned oxides was observed which is opposite to the trend for CP2-Ti. For all three techniques the oxide layer growth on the Ti-40Nb alloy follows the principal mechanisms that are established for Ti. Nb species are involved in the oxidation processes which causes significantly enhanced layer thickness growth, morphological changes and mixed oxides (Ti x Nb 1 − x )O 2 , more specific (Ti 0.75 Nb 0.25 )O 2 . All obtained oxide types appear to be promising as coatings of beta-type implants with appropriate bioactivity to stimulate bone growth.