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This study aimed to fabricate three-dimensional (3D) bioactive Sr2+ -substituted apatite (Sr-HAP) scaffolds prepared by gel-casting with polymer sponge infiltration technique. 3D Sr-HAP scaffolds were prepared as engineering constructs with interconnected porous structure with a pore size of 200-600 μm ranging from a 10 × 10 × 6 mm size was designed. The characterization of X-ray diffraction, field emission scanning electron microscopy, and energy dispersion spectroscopy was utilized in order to evaluate the crystalline phase, structure, and morphology in the interconnected porous of the synthesized Sr-HAP scaffold. The bioactive and biocompatible of the resultant Sr-HAP scaffolds were analyzed by using simulated body fluid solution. Furthermore, the cytotoxicity and proliferation of MG-63 cell lines on the scaffolds were examined in 24 h culture. Furthermore, in vivo experiments demonstrated that the tibia bone defect with 4 mm diameter in rabbits was successfully healed by Sr-HAP porous scaffold after 45 days implantation. The histological images indicated the improved cell proliferation and new bone formation occurred in the porous scaffold treated group. The results indicated that the fabricated Sr-HAP scaffold is a promising capacity to infuse bone regeneration and promote in vivo tissue repair.

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The AC magnetically induced heating characteristics of uncoated and silica-coated magnetic iron oxide nanoparticles dispersed in liquids of different viscosities were investigated. The aim was to synthesize and prepare uncoated and silica-coated nanoparticles of maghemite, and evaluate their ability to hyperthermically dissipate heat under an applied AC magnetic field when they are dispersed in liquids of different viscosities. A conceptual approach on the relative contributions of the Neel and the Brownian relaxation mechanisms to the hyperthermic heating of these suspensions is proposed. The microstructure, the physical and chemical properties of the uncoated and silica-coated nanoparticles were assessed by transmission electron microscopy; powder X-ray diffraction; 57Fe Mossbauer spectroscopy; Fourier transform infrared spectroscopy; zeta potential measurements; and conventional chemical analysis. Results of the Rietveld refinement of the XRD patterns and analysis of the collected Mossbauer data are well consistent with maghemite as being the only iron oxide phase. The mean diameters of the uncoated nanoparticles increased from ~6 to 7 nm, to 35 and 78 nm, for added silica coating amounts varying from 1 to 6-fold, respectively. Zeta potential measurements confirmed the efficiency of the nanoparticles sol-gel coating method. When dispersed in low viscosity media (water, triethanolamine, ethylene glycol), uncoated nanoparticles efficiently release heat via both Neel and Brown relaxation mechanisms under an applied oscillating magnetic field, achieving a temperature raise of approximately 21 °C. The silica layers tend to inhibit the Brownian motion of coated particles, making heat dissipation to be preferentially governed by the Neel relaxation of the magnetization vector. This leads to modest rises in temperature of 9 °C when they are dispersed in water or in the PVC (polyvinyl chloride). SAR tests indicate that the maghemite-silica core-shell systems might be useful for advanced technologies in medical practices based on local hyperthermia, particularly in oncology.

Over the last three decades, a variety of additive manufacturing techniques have gradually gained maturity and will potentially play an important role in future manufacturing industries. Among them, direct ink writing has attracted significant attention from both material and tissue engineering areas, where the colloidal ink is extruded and dispensed according to a pre-designed path, usually in the X-Y plane with suitable increments in the Z direction. Undoubtedly, this way of disassembling geometries, simple or complex, can facilitate most of the printing process. However, for one extreme case, i.e. pillar arrays, the size resolution can deviate from both nozzle and design if the common way of slicing and additive manufacturing is used. Therefore, a different printing path is required – directly depositing pillars in a converse gravitational direction. This paper gives multiple examples of printing viscoelastic colloidal ceramic and metal inks uniaxially and periodically into free-standing and height-adjustable pillar arrays. It is expected to inspire the additive manufacturing community that more versatile degrees of freedom and complex printing paths, not confined within only complex shapes, can be achieved by ink-based 3D printing.

In view of recent energy crisis and environmental considerations, reductions of melting temperature and CO2 emissions during the production of commercial soda lime silicate (SLS) glass at industrial scale are major intentions. Here we show that this goal can be achieved by using carbonate-free borate minerals such as colemanite (Ca2B6O11·5H2O) and borax penta-hydrate (BPH, Na2B4O7·5H2O) as alternative sources for CaO and Na2O, respectively. The SLS glass melting temperature has decreased successively by the incorporation of B2O3 with substitution of equivalent wt% SiO2 resulting from gradual utilization of colemanite and BPH. Hot Stage Microscopy (HSM) revealed that the melting temperature was decreased from 1650 °C, for the parent commercial SLS glass, to 1528 °C on use of colemanite and further down to 1072 °C on utilization of both colemanite and appropriate quantity of BPH up to which the properties of the pristine glass can be retained. Thus, energy consumption equivalent to reduction in melting temperature could be minimized during the glass production. Another important environmental benefit achieved by using carbonate free minerals is significant reduction (12%) of CO2 emissions during thermal decomposition in glass melting which could minimize greenhouse gas to the atmosphere at a great extent. Further, the addition of colemanite improved micro-hardness, elastic modulus and thermal properties of the pristine glass through polymerization of glass network structure. In contrast to the use of BPH as a source of more than 8 wt% Na2O deteriorated glass properties with the formation of non-bridging oxygens into the glass network.

The present work elucidates about the structure of bioactive glasses having chemical compositions expressed as (mol %) (50.0 - x)SiO2-xB2O3-9.3Na2O-37CaO-3.7P2O5, where x = 0.0, 12.5, 25, and 37.5, and establishes a correlation between the structure and thermal stability. The structural modifications in the parent boron-free glass (B0) with the gradual substitutions of B2O3 for SiO2 are assessed by Raman and 29Si, 31P, 11B, and 23Na magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopies. The structural studies reveal the presence of QSi2 and QSi3 structural units in both silicate and borosilicate glasses. However, QSi4(3B) units additionally form upon incorporating B2O3 in B0 glass. B-containing silicate glasses exhibit both three-coordinated boron (BIII) and four-coordinated boron (BIV) units. The 31P MAS-NMR studies reveal that the majority of phosphate species exist as isolated orthophosphate (QP0) units. The incorporation of B2O3 in B0 glass increases the cross-linking between the SiO4 and BO4 structural units. However, incorporation of B2O3 lowers the glass thermal stability (ΔT), as shown by differential scanning calorimetry. Although both silicate and borosilicate glasses exhibit good in vitro apatite-forming ability and cell compatibility, the bactericidal action against Escherichia coli bacteria is more evident in borosilicate glass in comparison to silicate base glass. The controlled release of (BO3)3- ions from boron-modified bioactive glasses improves both the cell proliferation and the antibacterial properties, making them promising for hard tissue engineering applications.

This paper reports the hierarchical influence of co-doping copper and lanthanum in a sol–gel derived quaternary (Si, Ca, Na, P) bioactive glass on its sintering ability. The mutual effects of Cu & La on density, crystallisation and sinterability were investigated using Taguchi analysis. Thermal properties of bioglasses were assessed by DTA/TGA and dilatometry, while crystallisation phase evolution of was monitored by X–ray diffraction. Ten glass compositions were sintered at two temperatures (800 and 900 °C). The glass structure was analysed by MAS–NMR, the sintered density measured, and sintered microstructures observed by SEM/EDS. Results revealed that Cu promotes early densification, enhancing density at lower sintering temperatures. Oppositely, beneficial sintering effects of La might be observed at higher sintering temperatures (>1000 °C). These differences are induced by the distinct roles of doping elements on devitrification upon increasing their concentrations: crystallisation is promoted by Cu and is inhibited by La.

The ability of manganese to induce early zircon (ZrSiO4) crystallization is investigated. An assorted range of manganese additions to the ZrO2 SiO2 binary system through a Sol-Gel approach is attempted to achieve ZrSiO4 formation at low temperatures. XRD analysis alongside complementary Rietveld refinement tool has been used to determine the propelling effect of manganese on the low temperature formation of ZrSiO4. The results revealed the ability of 5 wt% manganese to induce the ZrSiO4 formation at 900 °C through its occupancy at the ZrO2 lattice. The lattice substitution of Zr4+ by the lower sized Mn2+ and the concomitant lattice distortion of ZrO2 have been determined as the prime reason for manganese to enhance the reaction kinetics with amorphous SiO2 to yield ZrSiO4. Increments in the manganese content beyond 5 wt% are rejected by the ZrO2 lattice, making the excess to crystallize as Mn2O3. The colour change of ZrSiO4 is directly influenced by the manganese content in ZrO2 SiO2 binary system.

Magnetic spinel ferrite particles were successfully prepared from only iron (III) nitrate, using clove and cinnamon plant extracts for the first time as eco-fuels for auto–ignition synthesis. Both natural substances were shown to play dual roles in the synthesis of the magnetic particles; i.e. as fuels (agents for biogenic reduction), and as anti–oxidants for preserving the magnetic phases during subsequent heating. In this regard, no special protective environments such as H2/N2 or argon gases were required during the heat stabilisation process, and samples could be stabilised by heating to 550 °C in air. The magnetic crystalline phase is mostly maghemite (γ-Fe2O3) rather than magnetite (Fe3O4), as revealed by Raman, since no Raman active phonon modes were detected for magnetite, and most of the bands were related to maghemite, with traces of hematite. Both fuels produced strongly magnetic soft ferrites, with magnetisation values of 75 A m2 kg−1, around the expected ones for maghemite Moreover, TG curves showed that maghemite degradation only occurs at relatively high temperatures, namely at 550 °C for Clove, and at 744 °C for Cinnamon, confirming the sustainable nature of the as-obtained materials against oxidation.

This article reports the first robocasting of a sol–gel based glass ceramic scaffold. Sol–gel bioactive glass powders usually exhibit high volume fractions of meso– and micro–porosities, bad for colloidal processing as this adsorbs significant portion of the dispersing medium, affecting dispersion and flow. We circumvent these practical difficulties, to achieve pastes with particle size distributions, high solids loading and appropriate rheological properties for extrusion through fine nozzles for robocasting. Scaffolds with different macro-pore sizes (300–500 μm) with solid loadings up to 40 vol.% were robocast. The sintered (800 °C, 2 h) scaffolds exhibited compressive strength of 2.5–4.8 MPa, formed hydroxyapatite after 72 h in SBF, and had no cytotoxicity and a considerable MG63 cells viability rate. These features make the scaffolds promising candidates for tissue engineering applications and worthy for further in vivo investigations.

The impact of selective rare-earth (RE) additions in ZrO2-based ceramics on the resultant crystal structure, mechanical, morphological, optical, magnetic, and imaging contrast features for potential applications in biomedicine is explored. Six different RE, namely, Yb3+, Dy3+, Tb3+, Gd3+, Eu3+, and Nd3+ alongside their variations in the dopant concentrations were selected to accomplish a wide range of combinations. The experimental observations affirmed the roles of size and dopant concentration in determining the crystalline phase behavior of ZrO2. The significance of tetragonal ZrO2 (t-ZrO2) → monoclinic ZrO2 degradation is evident with 10 mol % of RE substitution, while RE contents in the range of 20 and 40 mol % ensured either t-ZrO2 or cubic ZrO2 (c-ZrO2) stability until 1500 °C. High RE content in the range of 80–100 mol % still confirmed the structural stability of c-ZrO2 for lower-sized Yb3+, Dy3+, and Tb3+, while the c-ZrO2 → RE2Zr2O7 phase transition becomes evident for higher-sized Gd3+, Eu3+, ...

A series of seven alkali-free silica-based bioactive glasses (SBG) with ZnO and/or SrO additives (in concentrations of 0–12 mol%) were synthesized by melt-quenching, aiming to delineate a candidate formulation possessing (i) a coefficient of thermal expansion (CTE) similar to the one of titanium (Ti) and its medical grade super-alloys (crucial for the future development of mechanically adherent implant-type SBG coatings) and (ii) antibacterial efficiency, while (iii) conserving a good cytocompatibility. The SBGs powders were multi-parametrically evaluated by X-ray diffraction, Fourier transform infrared and micro-Raman spectroscopy, dilatometry, inductively coupled plasma mass spectrometry, antibacterial (against Staphylococcus aureus and Escherichia coli strains) suspension inhibition and agar diffusion tests, and human mesenchymal stem cells cytocompatibility assays. The results showed that the coupled incorporation of zinc and strontium ions into the parent glass composition has a combinatorial and additive benefit. In particular, the “Z6S4” formulation (mol%: SiO2—38.49, CaO—32.07, P2O5—5.61, MgO—13.24, CaF2—0.59, ZnO—6.0, SrO—4.0) conferred strong antimicrobial activity against both types of strains, minimal cytotoxicity combined with good stem cells viability and proliferation, and a CTE (~ 8.7 × 10−6 × °C−1) matching well those of the Ti-based implant materials.

This research details the successful fabrication of scaffolds by robocasting from high silica sol–gel glass doped with Cu2+ or La3+. The parent HSSGG composition within the system SiO2–CaO–Na2O–P2O5 [67% Si – 24% Ca – 5% Na – 4% P (mol%)] was doped with 5 wt% Cu2+ or La3+ (Cu5 and La5). The paper sheds light on the importance of copper and lanthanum in improving the mechanical properties of the 3–D printed scaffolds. 1 h wet milling was sufficient to obtain a bioglass powder ready to be used in the preparation of a 40 vol% solid loading paste suitable for printing. Moreover, Cu addition showed a small reduction in the mean particle size, while La exhibited a greater reduction, compared with the parent glass. Scaffolds with macroporosity between 300 and 500 µm were successfully printed by robocasting, and then sintered at 800 °C. A small improvement in the compressive strength (7–18%) over the parent glass accompanied the addition of La. However, a much greater improvement in the compressive strength was observed with Cu addition, up to 221% greater than the parent glass, with compressive strength values of up to ∼14 MPa. This enhancement in compressive strength, around the upper limit registered for human cancellous bones, supports the potential use of this material in biomedical applications. Statement of Significance 3D porous bioactive glass scaffolds with greatly improved compressive strength were fabricated by robocasting from a high silica sol–gel glasses doped with Cu2+ or La3+. In comparison to the parent glass, the mechanical performance of scaffolds was greatly improved by copper-doping (>220%), while a modest increase of ∼9% was registered for lanthanum-doping. Doping ions (particularly La3+) acted as glass modifiers leading to less extents of silica polymerisation. This favoured the milling of the glass powders and the obtaining of smaller mean particle sizes. Pastes with a high solid loading (40 vol%) and with suitable rheological properties for robocasting were prepared from all glass powders. Scaffolds with dimensions of 3 × 3 × 4 mm and macro-pore sizes between 300 and 500 µm were fabricated.

3D printing emerged as a potential game-changer in the field of biomedical engineering. Robocasting in particular has shown excellent capability to produce custom-sized porous scaffolds from pastes with suitable viscoelastic properties. The materials and respective processing methods developed so far still need further improvements in order to obtain completely satisfactory scaffolds capable of providing both the biological and mechanical properties required for successful and comprehensive bone tissue regeneration. This work reports on the sol-gel synthesis of an alkali-free bioactive glass and on its characterization and processing ability towards the fabrication of porous scaffolds by robocasting. A two-fold increase in milling efficiency was achieved by suitably adjusting the milling procedures. The heat treatment temperature exerted a profound effect on the surface area of mesoporous powders. Robocasting inks containing 35 vol.% solids were prepared, and their flow properties were characterized by rheological tests. A script capable of preparing customizable CAD scaffold geometries was developed. The printing process was adjusted to increase the technique’s resolution. The mechanical properties of the scaffolds were assessed through compressive strength tests. The biomineralization ability and the biological performance were assessed by immersing the samples in simulated body fluid (SBF) and through MTT assays, respectively. The overall results demonstrated that scaffolds with macro porous features suitable for bone ingrowth (pore sizes of ~340 μm after sintering, and a porosity fraction of ~70%) in non-load-bearing applications could be successfully fabricated by 3D printing from the bioactive glass inks. Moreover, the scaffolds exhibited good biomineralization activity and good biocompatibility with human keratinocytes, suggesting they are safe and thus suited for the intended biomedical applications.

In bone tissue engineering, ceramics have been the choice due to their excellent biological properties. But the paradigm changed with the discovery of bioactive glasses (BGs) in 1969 by Larry Hench and co-workers, due to their ability to bond to living tissues through the formation of an interfacial bone-like hydroxyapatite layer when the bioglass was put in contact with biological fluids in vivo. Among a number of tested compositions, the one exhibiting the highest bioactivity index is the well-known trademarked 45S5 Bioglass®. The topic received increasing attention particularly after 1985 when this material entered in the market of biomedical devices, inspiring many other investigations aiming at further exploring the in vitro and in vivo performances of this BG, or developing other related BG compositions. The research efforts gradually revealed a number of shortcomings of 45S5 Bioglass®, mostly derived from its high sodium content, initially intended to decrease the melting temperature and accelerating the degradation of the silicate network over time. But the extensive release of sodium from 45S5 Bioglass® in the biological fluids creates a high pH cytotoxic environment. Other serious drawbacks include a fast degradation rate, and a poor sintering ability, which hinders the reliable fabrication of porous scaffolds. Therefore, sol-gel was regarded as an attractive alternative to prepare alkali-free BG compositions. The process uses inorganic and/or organic precursors, which undergo hydrolysis and condensation at room-temperature, being less costly. When properly conducted, the sol-gel process might result in amorphous structures with all the components intimately mixed at the atomic scale. Moreover, developing new better performing materials for bone tissue engineering is a growing concern, as the ageing of the world’s population leads to lower bone density and osteoporosis. This work describes the sol-gel synthesis of a novel quaternary silicate-based BG with the composition 60 SiO2 – 34 CaO – 4 MgO – 2 P2O5 (mol%) was prepared using acidified distilled water as single solvent. By controlling the kinetics of the hydrolysis and condensation steps, an amorphous glass structure could be obtained. The results of XRD of samples calcined within the temperature range from 600-900 ºC demonstrated that amorphous nature was maintained until 800 ºC, followed by partial crystallization at 900 ºC. The specific surface area, an important factor in osteoconduction, was also evaluated over different temperatures, ranging from 160.6 ± 0.8 m2/g at 600 ºC down to 2.2 ± 0.1 m2/g at 900 ºC, being accompanied consistent changes in average pore size and agreeing pore size distribution. The immersion of the BG particles in simulated body fluid (SBF) led to the formation of an extensive apatite layer on its surface. These overall results indicate the proposed material is very promising for biomedical applications in bone regeneration and tissue engineering.

The alleged formation of La-clusters in silicate glasses has received an overall consensus. However, recent and the current experimental results do not support this hypothesis for the structural role of La2O3 in glasses. Therefore, here we propose a new model for the assignment of the peaks in NMR spectra. All the experimental results here reported could be consistently explained by ascribing to La2O3 a network modifier role. Further, the proposed model could also explain the network modifier role of La2O3 in silicate glass compositions reported in literature where it was originally ascribed to form La-clusters. The La2O3 mitigated the LLPS due to increased entropy from the increasing number of different types of Qn structural units.

Transition metal ions are essential micronutrients for all living organisms and play an important role in bone metabolism. In the present study, we investigated the impact of transition metal ions (Cu, Co, Mn, Fe) on the structure and bioactivity of bioactive glasses. The emphasis was laid on understanding their influence on the chemical dissolution behavior of glasses and its impact on their vitro bioactivity, osteoblast proliferation and oxidative stress levels. The structure of glasses was studied by using molecular EXAFS in combination with Raman spectroscopy. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy after immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 and 7 days. A significant effect on the bioactivity was observed with addition of transition metal ions. The cellular responses were observed in vitro on glass powders using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of transition metal ions (Cu, Co, Mn, Fe) released from the glasses is also discussed.

In this paper, we present a preliminary study and conceptual idea concerning 3D printing water-sensitive glass, using a borosilicate glass with high alkali and alkaline oxide contents as an example in direct ink writing. The investigated material was prepared in the form of a glass frit, which was further ground in order to obtain a fine powder of desired particle size distribution. In a following step, inks were prepared by mixing the fine glass powder with Pluoronic F-127 hydrogel. The acquired pastes were rheologically characterized and printed using a Robocasting device. Differential scanning calorimetry (DSC) experiments were performed for base materials and the obtained green bodies. After sintering, scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were carried out in order to examine microstructure and the eventual presence of crystalline phase inclusions. The results confirmed that the as obtained inks exhibit stable rheological properties despite the propensity of glass to undergo hydrolysis and could be adjusted to desirable values for 3D printing. No additional phase was observed, supporting the suitability of the designed technology for the production of water sensitive glass inks. SEM micrographs of the sintered samples revealed the presence of closed porosity, which may be the main reason of light scattering.

This work reports on a preliminary study aimed at developing an industrial liquid fuel derived from charcoal and vegetable oil. Its relevance relies on the high energy potential of charcoal, its renewable nature, storage and transportation capacity in liquid form, as well as on the economic and environmental advantages derived thereof. The ability of a commercially available charcoal to be dispersed in three different organic solvents was assessed through the rheological characterisation of the resulting charcoal oil slurries (ChOS). The charcoal was ground in a conventional ball mill and dispersed with the aid of three different surfactants. The effects of the most relevant factors influencing the rheological properties of the suspensions were evaluated, including: (i) the solvent producing the lowest fuel viscosity (η) at a given charcoal content; (ii) the most efficient surfactant (and its amount) minimising the fuel viscosity (η) at a given solids fraction; and (iii) the charcoal content, which should be as high as possible. High-stability ChOS containing 62 wt% solids and 0.4 wt% surfactant, and exhibiting adequate flow properties and high calorific values, were successfully obtained.

Alpha-tricalcium phosphate (α-TCP) is a component of particular interest in the formulation of apatitic calcium phosphate based bone cements. During the setting reaction of this type of cements, a calcium deficient hydroxyapatite with composition similar to bone hydroxyapatite is formed. But the purity levels of the commercially available products based on α-TCP are generally low, and their prices are prohibitive. Such stringent conditions are pushing most of the researchers in the area of bone cements towards preparing α-TCP in their own laboratories. The low degree of purity of α-TCP based products is generally due to an incomplete β-TCP → α-TCP phase transformation and/or to a partial α-TCP → β-TCP reversal during cooling. Despite extensive research efforts, contradictory reports exist about the effects of composition of the starting material, cooling rates and the importance of quenching for maintaining α-TCP purity. The present work aims at shedding further light on this issue by controlling the relevant parameters of wet synthesis of the starting β-TCP powders and their heat treatment schedule in order to transform them in high purity α-TCP products. The key experimental variables investigated included the composition of the starting β-TCP powders, namely the Ca/P ratio, the maximum heat treatment temperatures, and the cooling rates.

The addition of resorbable β-tricalcium phosphate (β-TCP) to other bone substitute materials such as hydroxyapatite (HA) has been pointed out as a suitable strategy to enhance the regenerative potential of bone grafts made thereof. To check the generalization of this hypothesis, a new synthetic composite bone graft material consisting of a mixture of 30 vol% of pure β-TCP and 70 vol% of FastOs®BG (an alkali-free bioactive glass - BG) was prepared and tested in vivo. The in vivo performance of the new synthetic bone graft (30β-TCP-70FastOs®BG) was compared with those of FastOs®BG alone and of adbone®BCP, a biphasic calcium phosphate, consisting of 75% of HA and 25% of β-TCP. Two defects with 4 mm diameter were performed in Wistar rats calvaria and filled with the bone graft materials. The animals were sacrificed after 9 weeks of implantation and the calvaria was excised. Empty bone defects were used as negative control. The percentages of new bone formed (von Kossa staining) were always higher in the treated groups (FastOs®BG, 30β-TCP-70FastOs®BG and adbone®BCP) than in empty group. There were differences with statistical significance between empty and FastOs®BG groups and between empty and adbone®BCP groups. But the differences observed between empty and 30β-TCP-70FastOs®BG groups were less remarkable. The results demonstrated the superior bone regeneration ability of FastOs®BG alone, which was not further enhanced by adding β-TCP in the composition, confirming its already proven regenerative potential.

During the last decades, the nucleation and crystallization of the Li2O − SiO2 system has been widely investigated and its particular theoretical features disclosed. However, multicomponent lithium disilicate systems, being of higher technological interest, still require further studies aiming at better tailoring their relevant mechanical and chemical properties. Here we report on the effects of SiO2/Li2O molar ratio and the addition of P2O5 on the structure and crystallization behaviour of multicomponent lithium disilicate based glasses. Two non-stoichiometric P2O5-free lithium disilicate based glasses featuring equimolar contents of K2O and Al2O3 and with SiO2/Li2O molar ratios of 2.62 and 2.92 were synthesized in the Li2O − SiO2 system through the melt-quench technique. The influence of partially replacing (K2O + Al2O3) by P2O5 while keeping the same SiO2/Li2O molar ratios of P2O5-free glasses was investigated. The structural features of glasses were assessed by nuclear magnetic resonance. Differential thermal analysis was used to study crystallization kinetics and the crystalline phase evolution was followed by X-ray diffraction. The results showed that an increase in SiO2/Li2O molar ratio decreased the overall crystallization rate, preventing the formation of lithium disilicate. However, adding P2O5 had an opposite effect, enhancing the formation of fine lithium disilicate crystals. The nucleating role of P2O5 is discussed.

A BaCO3/BaSnO3/SnO2 nanocomposite has been prepared using a co-precipitation method without adding any additives. The prepared sample was characterized by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. Detailed studies on the dielectric and electrical behavior (dielectric constant, complex impedance Z*, ac conductivity, and relaxation mechanisms) of the nanocomposite have been performed using the nondestructive complex impedance spectroscopy technique within the temperature range 150–400 K. The dielectric constant of the sample as a function of temperature showed the typical characteristics of a relaxor. The maximum dielectric constant value was observed to depend on frequency. The non-monotonic relaxation behavior of the prepared nanocomposite was evidenced from the spectra of loss tan, tan(δ). The relaxation kinetics was modeled using a non-Arrhenius model.

This study addresses the preparation of hybrid nanoparticles comprised of magnetite (Fe3O4) cores and a surface functionalized with tetramethylammonium hydroxide (TMAOH). The stabilized core nanoparticles were subsequently coated with a polymer matrix consisting of poly(L-co-D,L lactic acid-co-trimethylene carbonate) and poly(ethylene oxide) − poly(propylene oxide) − poly(ethylene oxide) triblock copolymer. The novel core/shell hybrid nanoparticles combine the concepts of electromagnetic heating by the magnetite cores with the drug storage and release ability of the polymeric shell. These multifunctional hybrid nanoparticles are intended for hyperthermia clinical protocols in local drug delivery and medical practices in oncology. The essential physical features of these hybrid composite nanoparticles were assessed using an array of appropriate advanced characterization techniques. The equivalent average diameters of the composite nanoparticles were relatively uniform and their core/shell mass ratio was estimated through thermogravimetric analysis. The weakening of the intermolecular interactions with decreasing thickness of the coating led to a concomitant decrease in the melting temperature of the shell. The polydispersity index data from dynamic light scattering analysis enabled the conclusion that polymeric species contained in 10 mL of the polymeric matrix solution could effectively coat a maximum of core particles contained in 0.5 mL of ferrofluid.

Biphasic [hydroxyapatite (HA) + β -tricalcium phosphate ( β -TCP)] calcium phosphate powders with partial substitutions of Ca 2+ by silver, copper, zinc and strontium ions were synthesized by precipitation. The aim was to improve the overall biological performance (antimicrobial effect and stimulated osteoblasts proliferation) of the bone graft materials made thereof. The prepared powders were calcined and characterized by different techniques including X-ray diffraction (XRD), elemental analysis, thermo gravimetric and differential thermal analysis (TG-DTA), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). Rietveld refinement was used for quantitative phase analysis. The in vitro biocompatibility and the antibacterial activity of the powders were evaluated through the resazurin viability test with MG63 cells, and against Escherichia coli and Staphylococcus aureus , respectively. The quantitative elemental analysis revealed that only strontium ions have been fully incorporated into both HA and β -TCP phases. The in vitro biocompatibility with pre-osteoblastic cells was proved for all synthesized powders, while only the silver-doped powders exhibited antimicrobial activity against S. Aureus . The information gathered is of high relevance for designing improved calcium phosphate bioceramics.

Sol-gel glasses in quaternary silica-sodium-calcium-phosphorous systems have been synthesized using a rotary evaporator for rapid drying without ageing. This novel fast drying method drastically decreases the total drying and ageing time from several weeks to only 1 hour, thus overcoming a serious drawback in sol-gel preparation procedures for bioglasses. This work investigates the bioactivity behavior of two glasses synthesized by this fast method, with Ca:P ratios of 1.5, and 1.67. X-ray diffraction (XRD), Inductive coupled plasma, Fourier-transform infrared, and Raman spectroscopy were used to confirm the bioactivity of the synthesized powders. MAS-NMR was also used to assess the degree of silica polymerization. The composition with a higher Ca:P = 1.67 ratio showed better bioactivity in comparison to the one with Ca:P = 1.5, which exhibited little bio-response with up to 4 weeks of immersion in SBF (simulated body fluid). It was also found that an orbital agitation rate of 120 rpm favors the interfacial bio-mineralization reactions, promoting the formation of a crystalline hydroxyapatite (HAp) layer at the surface of the (Ca:P = 1.67) composition after 2 weeks immersion in SBF. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 510-520, 2018.

An assessment is undertaken for the formation of anorthite crystalline phase in a melilite-based glass composition (CMAS: 38.7CaO–9.7MgO–12.9Al2O3–38.7SiO2 mol %), used as a sealing material in solid oxide fuel cells, in view of the detrimental effect of anorthite on the sealing properties. Several advanced characterization techniques are employed to assess the material after prolonged heat treatment, including neutron powder diffraction (ND), X-ray powder diffraction (XRD), 29Si and 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR), and in situ Raman spectroscopy. ND, 29Si MAS-NMR, and 27Al MAS-NMR results revealed that both Si and Al adopt tetrahedral coordination and participate in the formation of the network structure. In situ XRD measurements for the CMAS glass demonstrate the thermal stability of the glass structure up to 850 °C. Further heat treatment up to 900 °C initiates the precipitation of melilite, a solid solution of akermanite/gehlenite crystalline phase. Qualitative XRD data for glass-ceramics (GCs) produced after heat treatment at 850 °C for 500 h revealed the presence of anorthite along with the melilite crystalline phase. Rietveld refinement of XRD data indicated a high fraction of glassy phase (∼67%) after the formation of crystalline phases. The 29Si MAS-NMR spectra for the CMAS-GC suggest the presence of structural units in the remaining glassy phase with a polymerization degree higher than dimer units, whereas the 27Al MAS-NMR spectra revealed that most Al3+ cations exhibit a 4-fold coordination. In situ Raman spectroscopy data indicate that the formation of anorthite crystalline phase initiated after 240 h of heat treatment at 850 °C owing to the interaction between the gehlenite crystals and the remaining glassy phase.

In this study, nanocrystalline ZnO–SnO2 mixed metal oxide powder was prepared by co-precipitation using Zn(CH3COO)2∙2H2O and SnCl4∙5H2O as precursor materials. The powder was characterized by X–ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Williamson–Hall method was used to evaluate the micro structural parameters of ZnO–SnO2 such as crystallite sizes and lattice strain. The photoluminescence property of the sample was studied at different temperatures (10–300 K). Results showed that the emission intensity decreases with temperature increasing. The photocatalytic activity at the gas–solid interface was assessed by monitoring the degradation of nitrogen oxides, a major atmospheric pollutant. The results show that the nanocrystalline ZnO–SnO2 mixed metal oxide powder exhibits higher and more stable photocatalytic activity against photocorrosion than ZnO alone.

We report on the fabrication of multiscale three-dimensional (3D) micropatterning of 0.5Ba(Zr0.2Ti0.8)O3 − 0.5(Ba0.7Ca0.3)TiO3 (BZT − BCT) electroceramic material using soft lithographic PDMS moulds. The ceramic microcomponents were successfully consolidated by Epoxy Gel Casting from stable aqueous suspension of BZT-BCT material. A successful aqueous processing of electroceramic material was employed with surface protection of powder particles against hydrolysis as considerably an important parameter to achieve high solid loading suspension with pseudoplastic behaviour suitable for casting in micro scale moulds. The process to obtain micro sized pattern of material was divided in two steps: (i) production of high quality SU-8 master moulds and the respective negative replicas in PDMS (soft mould) by photolithography and soft mould replication, respectively; (ii) casting the soft moulds by stable high solid loading BZT-BCT suspensions in presence of gelation agents followed by de-moulding, drying and sintering. The resulting green micropattern structures show interesting features, including complex structures with a periodic variations through their length and, multiscale array of hexagonal shaped pillars of different aspect ratios (AR) (max AR ≈ 8 with approx ∼320 μm of height and side length ∼40 μm) with smooth side wall features along height. The green pillar arrays were further sintered to show the suitability of aqueous processing of material and proposed casting method.

This work deals with the fabrication by robocasting of 3D porous scaffolds of an alkali-free bioactive glass composition, FastOs®BG, belonging to the diopside (CaMgSi2O6)–fluorapatite (Ca5(PO4)3F)–tricalcium phosphate (Ca3(PO4)2) system. A glass frit prepared by melt quenching was grinded by dry and wet milling up to getting a suitable combination of particle sizes. The milled frit was then dispersed in aqueous media with the addition of a polycarbonate dispersant, hydroxypropyl methylcellulose (HPMC) as binder and Aristoflex® TAC as gelation agent. The effects of the type and amounts of the processing additives and particle size distribution on the rheological properties of the extrudable pastes were investigated. Printable inks containing 47 vol.% solids with rheological properties tuned to meet the stringent requirements of robocasting technique were obtained. Scaffolds with totally interconnected 3D pore networks and different pore sizes (200, 300 and 500 µm) could be easily fabricated and sintered. The excellent processing and sintering ability resulted in compressive strength values comparable to that of cancellous bone essential for 3D porous scaffolds intended for bone regeneration and tissue engineering applications.

Composite powders comprising various proportions of β-Tricalcium phosphate [β-Ca3(PO4)2] and α-Alumina (α-Al2O3) were synthesized by wet precipitation and then heat treated for drying and crystalline phase development. The phase formation mechanism was assessed through a set of characterization techniques including XRD, FT-IR and Raman spectra, and quantitative Rietveld refinement analysis. Al2O3 additions delayed the transformation kinetics from calcium deficient apatite to β-Ca3(PO4)2 and preserved the thermal stability of β-Ca3(PO4)2 − α-Al2O3 composites till 1400 °C. Such enhancement of thermal stability was due to the occupancy of Al3+ at both Ca2+(4) and Ca2+(5) lattice sites of β-Ca3(PO4)2. Beyond the occupancy saturation limit for Al3+, the excess of aluminium crystallized as α-Al2O3. Morphological analysis revealed the growth of rod-like α-Al2O3 platelets on the surface of micron sized β-Ca3(PO4)2 grains. The mechanical data obtained from indentation of bulk composites displayed enhanced hardness and Young’s modulus with increasing α-Al2O3 content in the composites.

ZnO/ZnFe 2 O 4 nanocomposite was prepared by a simple and low cost chemical precipitation method. The prepared composite was characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX), Raman and Fourier Transform infrared spectroscopy (FTIR). The morphology of the prepared sample was studied by scanning electron microscopy (SEM). Photoluminescence (PL) emission of the sample has been investigated at different temperatures (10–300 K) in order to determine the effect of temperature on emission properties of the prepared composite. It was found that at low temperature, the samples show stronger emissions than those at room temperature. Magnetic properties of ZnO/ZnFe 2 O 4 nanocomposite was discussed in temperature range of 5–300 K using VSM measurement. The effective anisotropy constant K eff , extracted from the magnetization vs. magnetic field, M(B), experimental curve obtained at 5 K and using the law of saturation magnetization, was found to be 2.3 × 10 6 erg/cm 3 . The high value of anisotropy constant is attributed to the existence of uncompensated surface spin in our sample as well as the magnetocrystalline contribution (which depends on the inversion degree in ZnFe 2 O 4 ). By using of a modified Langevin equation, the contribution of the surface spins was quantitatively calculated in different temperature higher than T B . It was found that as the temperature increases from 100 K to 300 K, the surface spins contribution in the total magnetization increases from 44% to 68%.

Cadmium is a chemical element that finds application in many fields. As a consequence of the numerous human activities related to its wide spread applications, the environment gets contaminated. One of the most severe consequences happens in aquatic habitats. Cadmium removal from aqueous solution by many different materials has been studied. However, the limited ability of the existing models to fit the experimental data, determination of important parameters such as mass of extracted heavy metal per unit mass of decontaminant, or predict how fast the process will occur, such as adsorption kinetics constants, is still a concern. In this work, two models are used to fit the adsorption data gathered at different temperatures by two distinct decontaminant calcium phosphate (CaP) powders, hydroxyapatite (HAp) and tricalcium phosphate (β-TCP). The fitting models are nonlinear forms of pseudo first-order adsorption kinetics and the pseudo second-order adsorption kinetics. Determination of important parameters of both models was performed for both HAp and β-TCP under each of the experimental conditions used. The results disclose very interesting adsorption properties of cadmium ions from aqueous media by β-TCP.

Children and adolescents living in residential childcare have a higher prevalence of mental health problems as a result of a history of adverse childhood experiences. Therefore, this population should be a priority target for mental health preventive interventions. The current study analyses the effectiveness of the Wave by Wave surf therapy program, that combines surfing with a psychological group intervention, through a randomized controlled trial. Seventy-three youth (7-17 years) living in residential care participated in the study. Main mental health outcomes (adjustment problems, depression, anxiety, and wellbeing) and secondary outcomes (self-efficacy, self-regulation, sleep quality, physical activity, pro-social behavior, and social connectivity) were assessed at pre- and post-intervention. The results indicated a significant impact of the intervention on mental health outcomes reported by the key residential worker, with medium to large effect sizes. Specifically, after the intervention, there was a significant reduction in the total emotional and behavioural problems, and a significant increase of youth pro-social behaviour and quality of life that was not observed for the waiting list group. There were no significant effects on other measures reported by the children (e.g., depression and anxiety, self-esteem, emotion regulation, social connectedness, sleep quality, physical activity) and on executive functions measures. The Wave by Wave program seems to be an effective intervention to reduce behavior problems and to promote pro-social behavior in a high-risk sample. The absence of significant effects on other dimensions may indicate the need of some complementary support to address specific difficulties of this population. Efectividad de una intervención preventiva psicológica y de surf combinada con niños y adolescentes en cuidado residencial: Un ensayo controlado aleatorizado. Los niños y adolescentes que viven en acogimiento residencial tienen una mayor prevalencia de problemas de salud mental. Por lo tanto, esta población debe ser un objetivo prioritario para las intervenciones preventivas de salud mental. El estudio actual analiza la efectividad del programa Wave by Wave, que combina el surf con una intervención psicológica grupal, a través de un ensayo controlado aleatorio. Setenta y tres jóvenes (7-17 años) que viven en acogimiento residencial participaron en el estudio. Los principales resultados de salud mental (problemas de ajuste, depresión, ansiedad y bienestar) y los resultados secundarios (autoeficacia, autorregulación, calidad del sueño, actividad física, comportamiento prosocial y conectividad social) se evaluaron antes y después de intervención. Los resultados indicaron un impacto significativo de la intervención sobre los resultados de salud mental reportados por el cuidador en la residencia. Específicamente, después de la intervención, hubo una reducción significativa en los problemas emocionales y conductuales totales, y un aumento significativo del comportamiento prosocial de los jóvenes y de la calidad de vida que no se observó en el grupo control. No hubo efectos significativos en otras medidas reportadas por los niños (ex., depresión y ansiedad, autoestima) y en las medidas de las funciones ejecutivas. El programa Wave by Wave parece ser una intervención efectiva para reducir los problemas de comportamiento y promover el comportamiento prosocial en una muestra de alto riesgo. La ausencia de efectos significativos en otras dimensiones puede indicar la necesidad de algún apoyo complementario para abordar las dificultades específicas de esta población..

The main objective of this paper is to analyse the impacts of the overtaking lateral dis-tance between a bicycle and a motor vehicle (MV) on road safety and energy consump-tion at two-lane urban roads. An on-board sensor platform was installed on a probe bi-cycle to measure the overtaking lateral distance and dynamic data. The Bicycle Specific Power (BSP) methodology was used to estimate human required power to ride a bicy-cle while Vehicle Specific Power (VSP) was used for MVs. The results showed that 50% of overtaking lateral distance were lower than 0.5m in the peak hours. The BSP and VSP analyses for different values of overtaking lateral distance did not result in any relationship between variables. There was a good fit (R2 >0.67) between traffic volumes and overtaking lateral distance in the peak hours. On average, the MVs energy con-sumption in the afternoon was 92% higher than the morning peak periods. published

[EN] Exploring the reasons for the initiation of Al-O-Al bond formation in alkali-earth alumino silicate glasses is a key topic in the glass-science community. Evidence for the formation of Al-O-Al and Al-NBO bonds in the glass composition 38.7CaO-9.7MgO-12.9AlO-38.7SiO (CMAS, mol%) has been provided based on Molecular Dynamics (MD) simulations. Analyses in the short-range order confirm that silicon and the majority of aluminium cations form regular tetrahedra. Well-separated homonuclear (Si-O-Si) and heteronuclear (Si-O-Al) cluster regions have been identified. In addition, a channel region (C-Region), separated from the network region, enriched with both NBO and non-framework modifier cations, has also been identified. These findings are in support of the previously proposed extended modified random network (EMRN) model for aluminosilicate glasses. A detailed analysis of the structural distributions revealed that a majority of Al, 51.6%, is found in Si-O-Al links. Although the formation of Al-O-Al and Al-NBO bonds is energetically less favourable, a significant amount of Al is found in Al-O-Al links (33.5%), violating Lowenstein's rule, and the remainder is bonded with non-bridging oxygen (NBO) in the form of Al-NBO (Al-O-(Ca, Mg)). The conditions necessary for the formation of less favourable bonds are attributed to the presence of a high amount of modifier cations in current CMAS glass and their preferable coordination., A. R. A. and S. B. would like to thank Dr Muraleedharan K., Director, CSIR-CGCRI for his strong support and encouragement. A. R. A. gratefully acknowledges the financial support of the Budapest Neutron Centre, Hungary, for allotting beam time and financial support (BRR_407) under the NMI3-II program. Part of this work was developed in the scope of the CICECO-Aveiro Institute of Materials (UID/CTM/50011/2013) project, and funded by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and the Portuguese Foundation for Science and Technology (FCT). S. G. would like to thank the German Research Foundation (DFG) for financial support through the priority program SPP 1594 ‘‘Topological Engineering of Ultra-Strong Glasses’’ (project BI1453/1-2). Simulations were performed with computing resources granted by RWTH Aachen University under project rwth0297.

The combination of calcium phosphates with bioactive glasses (BG) has received an increased interest in the field of bone tissue engineering. In the present work, biphasic calcium phosphates (BCP) obtained by hydrothermal transformation of cuttlefish bone (CB) were coated with a Sr-, Mg- and Zn-doped sol-gel derived BG. The scaffolds were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The initial CB structure was maintained after hydrothermal transformation (HT) and the scaffold functionalization did not jeopardize the internal structure. The results of the in-vitro bioactivity after immersing the BG coated scaffolds in simulated body fluid (SBF) for 15 days showed the formation of apatite on the surface of the scaffolds. Overall, the functionalized CB derived BCP scaffolds revealed promising properties, but further assessment of the in-vitro biological properties is needed before being considered for their use in bone tissue engineering applications.

As a branch of direct 3D printing technique, Robocasting is a promising candidate to fulfil multiple material printing [1]. Currently, the Robocasting community commonly utilizes small amplitude oscillatory shear (SAOS) tests to evaluate the printability and stiffness of the pastes for Robocasting, while large amplitude oscillatory shear (LAOS) test has been neglected. However, SAOS experiments restrict the information about the rheological properties within the linear viscoelastic regime, providing information regarding the internal microstructure of the pastes at rest, i.e., before they start to flow. From the previous study on large amplitude oscillatory shear (LAOS) tests of polymer solutions and powder suspensions [2, 3], the Lissajous–Bowditch curves illustrate the gradually changing flow behaviours of those complex fluids. By imposing variable frequencies and shear strains to inks with both high elastic and viscous moduli, the same approach is used to assess their complex theological behaviours, aiming at further understanding their effects on the Robocasting process.

Ni- and Fe-doped CeO2 nanoparticles were prepared by a chemical co-precipitation method and then heat treated at 300 °C. The structural, morphological, and compositional properties of the prepared nanoparticles were studied by powder X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared (FT-IR) Spectroscopy. The powder XRD results revealed that all the samples exhibit the typical cubic fluorite structure of CeO2. The EDS and FTIR analyses confirmed the formation of CeO2 nanoparticles and the incorporation of Fe and Ni ions in the crystal lattice of CeO2. The photoluminescence (PL) properties were investigated to assess the effect of Fe- and Ni-doping on the emission properties of CeO2 nanoparticles. The impacts of the type of dopant on the dielectric properties and ac conductivity of the prepared nanoparticles were investigated. It was observed that the dielectric constant of Ni-doped CeO2 nanoparticles measured at low-frequency region is much greater than that of Fe-doped CeO2 nanoparticles. The difference was explained on the basis of interfacial/space charge polarization, with Ni-doped CeO2 nanoparticles having a more heterogeneous dielectric structure. The universal Jonscher power law was well adjusted to the ac conductivity spectra. It was shown that the Fe-CeO2 composite nanoparticles are less conductive than the Ni-doped CeO2 ones.

Currently, there is a considerable time-lag in the industrialisation of innovative technological solutions for the functionalization of osseous implants, with ever-demanding healthcare requirements (e.g., controlled release of therapeutic ions, match of biomaterial degradation – bone growth rates, antimicrobial efficiency). As third-generation biomaterials, phosphate bio-glasses (PBGs) have demonstrated an ability to stimulate specific biological responses from tissue to molecular level, by successfully coupling bioactive and resorbable material properties. Here, radio-frequency magnetron sputtered (RF-MS) PBGs were explored as sacrificial resorbable layers for prospective biomedical implant designs. A PBG powder with a 50–P2O5, 35–CaO, 10–Na2O and 5–Fe2O3 composition (mol%) was used as source (target) material. The influence of the argon working pressure (0.2–1 Pa) – one of the most prominent RF-MS variables – on the morphology, structure, uniformity, composition, degradation rate and cytocompatibility of PBG films was investigated. The engineered modification of physical-chemical and biological features of the PBG sputtered films was multi-parametrically surveyed by AFM, EDXS, spectroscopic ellipsometry, GIXRD, FTIR spectroscopy measurements and in vitro assays. Results suggested that the film thickness, composition, density and structure were preserved over a uniformity region having a diameter of ~30 mm, irrespective of sputtering pressure. The network connectivity and the surface porosity of the films were found to have antagonistic roles with respect to the in vitro degradation performance. The possibility of fine tuning the composition, structure and thereby biological interaction of the PBG films by conveniently modifying the sputtering pressure was shown (i.e., permitting their complete controlled degradation, without cytotoxic effects). This work is the first to show in vitro cytocompatibility outcomes of sputtered PBG films and their cross-area uniformity, and thus, it could prove to be an important technological step in their future biomedical application and suggest implications for future industrial scale-up.

Composites with varied proportions of β-Ca3(PO4)2 and ZnO were obtained through an in situ aqueous precipitation method under slightly basic (pH ≈ 8) conditions. The formation of β-Ca3(PO4)2 phase starts at an early heat-treatment stage (∼800 °C) and incorporates Zn2+ ions at both Ca2+(4) and Ca2+(5) sites of the lattice up to its occupancy saturation limit. The incorporation of Zn2+ in the β-Ca3(PO4)2 lattice enhances its thermal stability delaying the allotropic β-Ca3(PO4)2→α-Ca3(PO4)2 phase transformation. The excess zinc beyond the occupancy saturation limit precipitates as Zn(OH)2 and undergoes dehydroxylation to form ZnO at elevated temperatures. The presence of ZnO in the β-Ca3(PO4)2 matrix yields denser microstructures and thus improves the mechanical features of sintered composites up to an optimal ZnO concentration beyond which it tends to exert an opposite effect.

Good mechanical properties and high injectability are the major requirements to ensure widespread application of calcium phosphate cements (CPCs) as bone substitutes in minimally invasive surgeries. However, obtaining CPCs that exhibit a good compromise between these two properties as well as good biological performance is still a great challenge. This study presents novel solutions to improve these properties, which include (i) co-doping β-tricalcium phosphate (β-TCP) powder with Sr and Mn, and (ii) adding small amounts of saccharides (sucrose or fructose) to the setting-liquid solution. The combination of these two strategies enabled full injectability and significantly increased the wet compressive strength of CPCs in comparison to undoped or solely Sr-doped CPCs. Furthermore, the proliferative response of human MG63 osteoblastic cells, their rate of collagen-I secretion, and particularly their growth behaviour on the cement surfaces were also enhanced. The overall improved relevant properties of Mn/Sr co-doped CPCs with added sucrose, including in vitro biological performance, renders them very promising materials for bone regeneration and tissue engineering.