Browse
Submit Data
Databases
API
Help

Dataset Information

23 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Precipitation at Room Temperature as a Fast and Versatile Method for Calcium Phosphate/TiO₂ Nanocomposites Synthesis.

ABSTRACT: The constantly growing need for advanced bone regeneration materials has motivated the development of calcium phosphates (CaPs) composites with a different metal or metal-oxide nanomaterials and their economical and environmentally friendly production. Here, two procedures for the synthesis of CaPs composites with TiO₂ nanoplates (TiNPl) and nanowires (TiNWs) were tested, with the immersion of TiO₂ nanomaterials (TiNMs) in corrected simulated body fluid (c-SBF) and precipitation of CaP in the presence of TiNMs. The materials obtained were analyzed by powder X-ray diffraction, spectroscopic and microscopic techniques, Brunauer-Emmett-Teller surface area analysis, thermogravimetric analysis, dynamic and electrophoretic light scattering, and their hemocompatibility and ability to induce reactive oxygen species were evaluated. After 28 days of immersion in c-SBF, no significant CaP coating was formed on TiNMs. However, the composites with calcium-deficient apatite (CaDHA) were obtained after one hour in the spontaneous precipitation system. In the absence of TiNMs, CaDHA was also formed, indicating that control of the CaP phase formed can be accomplished by fine-tuning conditions in the precipitation system. Although the morphology and size of crystalline domains of CaDHA obtained on the different nanomaterials differed, no significant difference was detected in their local structure. Composites showed low reactive oxygen species (ROS) production and did not induce hemolysis. The results obtained indicate that precipitation is a suitable and fast method for the preparation of CaPs/TiNMs nanocomposites which shows great potential for biomedical applications.

SUBMITTER: Erceg I

PROVIDER: S-EPMC8230063 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Calcium phosphate precipitation inhibits mitochondrial energy metabolism.

Project description:Early studies have shown that moderate levels of calcium overload can cause lower oxidative phosphorylation rates. However, the mechanistic interpretations of these findings were inadequate. And while the effect of excessive calcium overload on mitochondrial function is well appreciated, there has been little to no reports on the consequences of low to moderate calcium overload. To resolve this inadequacy, mitochondrial function from guinea pig hearts was quantified using several well-established methods including high-resolution respirometry and spectrofluorimetry and analyzed using mathematical modeling. We measured key mitochondrial variables such as respiration, mitochondrial membrane potential, buffer calcium, and substrate effects for a range of mitochondrial calcium loads from near zero to levels approaching mitochondrial permeability transition. In addition, we developed a computer model closely mimicking the experimental conditions and used this model to design experiments capable of eliminating many hypotheses generated from the data analysis. We subsequently performed those experiments and determined why mitochondrial ADP-stimulated respiration is significantly lowered during calcium overload. We found that when calcium phosphate levels, not matrix free calcium, reached sufficient levels, complex I activity is inhibited, and the rate of ATP synthesis is reduced. Our findings suggest that calcium phosphate granules form physical barriers that isolate complex I from NADH, disrupt complex I activity, or destabilize cristae and inhibit NADH-dependent respiration.

| S-EPMC6336351 | biostudies-literature

Anatase TiO2 ultrathin nanobelts derived from room-temperature-synthesized titanates for fast and safe lithium storage.

Project description:Lithium-ion batteries (LIBs) are promising energy storage devices for portable electronics, electric vehicles, and power-grid applications. It is highly desirable yet challenging to develop a simple and scalable method for constructions of sustainable materials for fast and safe LIBs. Herein, we exploit a novel and scalable route to synthesize ultrathin nanobelts of anatase TiO2, which is resource abundant and is eligible for safe anodes in LIBs. The achieved ultrathin nanobelts demonstrate outstanding performances for lithium storage because of the unique nanoarchitecture and appropriate composition. Unlike conventional alkali-hydrothermal approaches to hydrogen titanates, the present room temperature alkaline-free wet chemistry strategy guarantees the ultrathin thickness for the resultant titanate nanobelts. The anatase TiO2 ultrathin nanobelts were achieved simply by a subsequent calcination in air. The synthesis route is convenient for metal decoration and also for fabricating thin films of one/three dimensional arrays on various substrates at low temperatures, in absence of any seed layers.

| S-EPMC4488874 | biostudies-other

Fast room temperature lability of aluminosilicate zeolites.

Project description:Aluminosilicate zeolites are traditionally used in high-temperature applications at low water vapour pressures where the zeolite framework is generally considered to be stable and static. Increasingly, zeolites are being considered for applications under milder aqueous conditions. However, it has not yet been established how neutral liquid water at mild conditions affects the stability of the zeolite framework. Here, we show that covalent bonds in the zeolite chabazite (CHA) are labile when in contact with neutral liquid water, which leads to partial but fully reversible hydrolysis without framework degradation. We present ab initio calculations that predict novel, energetically viable reaction mechanisms by which Al-O and Si-O bonds rapidly and reversibly break at 300?K. By means of solid-state NMR, we confirm this prediction, demonstrating that isotopic substitution of 17O in the zeolitic framework occurs at room temperature in less than one hour of contact with enriched water.

| S-EPMC6795794 | biostudies-literature

The Influence of Residuals Combining Temperature and Reaction Time on Calcium Phosphate Transformation in a Precipitation Process

Project description:Precipitation is one of the most common processes to synthesize hydroxyapatite, which is the human body’s mineral forming bone and teeth, and the golden bioceramic material for bone repair. Generally, the washing step is important in the precipitation method to remove the residuals in solution and to stabilize the phase transformation. However, the influence of residuals in combination with the reaction temperature and time, on calcium phosphate formation, is not well studied. This could help us with a better understanding of the typical synthesis process. We used a fixed starting ion concentration and pH in our study and did not adjust it during the reaction. XRD, FTIR, ICP-OES, and SEM have been used to analyze the samples. The results showed that combining residuals with both reaction temperature and time can significantly influence calcium phosphate formation and transformation. Dicalcium phosphate dihydrate formation and transformation are sensitive to temperature. Increasing temperature (60 °C) can inhibit the formation of acidic calcium phosphate or transform it to other phases, and further the particle size. It was also observed that high reaction temperature (60 °C) results in higher precipitation efficiency than room temperature. A low ion concentration combining reaction temperature and time could still significantly influence the calcium phosphate transformation during the drying.

| S-EPMC8883985 | biostudies-literature

A versatile method for generating semiconducting polymer dot nanocomposites.

Project description:This paper describes a method, based on co-precipitation, for generating small semiconducting polymer dot (Pdot) nanocomposites, which contain either gold or iron oxide nanoparticles within the Pdot matrix. We demonstrate the utility of Pdot-Au nanoparticles (Au-NP-Pdots) in dual-modality imaging in which co-localization of fluorescence from Pdot and scattering from Au was used to identify Au-NP-Pdot probes for downstream single-particle tracking and cellular imaging. We also demonstrate the potential of employing Pdot-FeO(x) nanoparticles (FeO(x)-NP-Pdots) for both sample preparation, where cells tagged with FeO(x)-NP-Pdots were isolated using an external magnet, and cellular imaging and detection, owing to the intense fluorescence from Pdots. The method we present here should be generalizable to the formation of other Pdot nanocomposites for creating the next generation of multi-functional Pdot probes.

| S-EPMC3500905 | biostudies-literature

Ultrafast room-temperature crystallization of TiO2 nanotubes exploiting water-vapor treatment.

Project description:In this manuscript a near-room temperature crystallization process of anodic nanotubes from amorphous TiO2 to anatase phase with a fast 30 minutes treatment is reported for the first time. This method involves the exposure of as-grown TiO2 nanotubes to water vapor flow in ambient atmosphere. The water vapor-crystallized samples are deeply investigated in order to gain a whole understanding of their structural, physical and chemical properties. The photocatalytic activity of the converted material is tested by dye degradation experiment and the obtained performance confirms the highly promising properties of this low-temperature processed material.

| S-EPMC4295093 | biostudies-literature

Nanoscale stacking fault-assisted room temperature plasticity in flash-sintered TiO2.

Project description:Ceramic materials have been widely used for structural applications. However, most ceramics have rather limited plasticity at low temperatures and fracture well before the onset of plastic yielding. The brittle nature of ceramics arises from the lack of dislocation activity and the need for high stress to nucleate dislocations. Here, we have investigated the deformability of TiO2 prepared by a flash-sintering technique. Our in situ studies show that the flash-sintered TiO2 can be compressed to ~10% strain under room temperature without noticeable crack formation. The room temperature plasticity in flash-sintered TiO2 is attributed to the formation of nanoscale stacking faults and nanotwins, which may be assisted by the high-density preexisting defects and oxygen vacancies introduced by the flash-sintering process. Distinct deformation behaviors have been observed in flash-sintered TiO2 deformed at different testing temperatures, ranging from room temperature to 600°C. Potential mechanisms that may render ductile ceramic materials are discussed.

| S-EPMC6984969 | biostudies-literature

Electrochemical Induced Calcium Phosphate Precipitation: Importance of Local pH.

Project description:Phosphorus (P) is an essential nutrient for living organisms and cannot be replaced or substituted. In this paper, we present a simple yet efficient membrane free electrochemical system for P removal and recovery as calcium phosphate (CaP). This method relies on in situ formation of hydroxide ions by electro mediated water reduction at a titanium cathode surface. The in situ raised pH at the cathode provides a local environment where CaP will become highly supersaturated. Therefore, homogeneous and heterogeneous nucleation of CaP occurs near and at the cathode surface. Because of the local high pH, the P removal behavior is not sensitive to bulk solution pH and therefore, efficient P removal was observed in three studied bulk solutions with pH of 4.0 (56.1%), 8.2 (57.4%), and 10.0 (48.4%) after 24 h of reaction time. While P removal efficiencies are not generally affected by bulk solution pH, the chemical-physical properties of CaP solids collected on the cathode are still related to bulk solution pH, as confirmed by structure characterizations. High initial solution pH promotes the formation of more crystalline products with relatively high Ca/P molar ratio. The Ca/P molar ratio increases from 1.30 (pH 4.0) to 1.38 (pH 8.2) and further increases to 1.55 (pH 10.0). The formation of CaP precipitates was a typical crystallization process, with an amorphous phase formed at the initial stage which then transforms to the most stable crystal phase, hydroxyapatite, which is inferred from the increased Ca/P molar ratio from 1.38 (day 1) to the theoretical 1.76 (day 11) and by the formation of needle-like crystals. Finally, we demonstrated the efficiency of this system for real wastewater. This, together with the fact that the electrochemical method can work at low bulk pH, without dosing chemicals and a need for a separation process, highlights the potential application of the electrochemical method for P removal and recovery.

| S-EPMC5628374 | biostudies-literature

A fast and sensitive room-temperature graphene nanomechanical bolometer.

Project description:Bolometers are a powerful means of detecting light. Emerging applications demand that bolometers work at room temperature, while maintaining high speed and sensitivity, properties which are inherently limited by the heat capacity of the detector. To this end, graphene has generated interest, because it has the lowest mass per unit area of any material, while also possessing extreme thermal stability and an unmatched spectral absorbance. Yet, due to its weakly temperature-dependent electrical resistivity, graphene has failed to challenge the state-of-the-art at room temperature. Here, in a departure from conventional bolometry, we use a graphene nanoelectromechanical system to detect light via resonant sensing. In our approach, absorbed light heats and thermally tensions a suspended graphene resonator, thereby shifting its resonant frequency. Using the resonant frequency as a readout for photodetection, we achieve a room-temperature noise-equivalent power (2?pW?Hz-1/2) and bandwidth (from 10?kHz up to 1.3?MHz), challenging the state-of-the-art.

| S-EPMC6797740 | biostudies-literature

Ultrahigh Selective Room-Temperature Ammonia Gas Sensor Based on Tin-Titanium Dioxide/reduced Graphene/Carbon Nanotube Nanocomposites by the Solvothermal Method.

Project description:Resistive-based gas sensors have been considered as the most favorable gas sensors for detection of toxic gases and volatile organic compounds (VOCs) because of their simple structure, low cost, high sensitivity, ease of use, and high stability. Unfortunately, wide application of resistive-based gas sensors is limited by their low selectivity. In this article, we present the fabrication of ultrahigh selective NH3 gas sensor based on tin-titanium dioxide/reduced graphene/carbon nanotube (Sn-TiO2@rGO/CNT) nanocomposites. The Sn-TiO2@rGO/CNT nanocomposites with different molar ratios of Sn/Ti (1:10, 3:10, and 5:10) were synthesized via the solvothermal method. Characterizations by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy confirmed the decoration of Sn-TiO2 nanoparticles on rGO/CNT nanocomposite surfaces. The Sn-TiO2@rGO/CNT nanocomposite gas sensor exhibited high response and ultrahigh selectivity to NH3 against toluene, dimethylformamide, acetone, ethanol, methanol, isopropanol, formaldehyde, hydrogen, carbon dioxide, acetylene, and VOCs in paint thinners at room temperature. The Sn-TiO2@rGO/CNT nanocomposite gas sensor with molar ratio of Sn/Ti = 1:10 showed the highest response to NH3 over other molar ratios of Sn/Ti as well as pure rGO/CNT and Sn-TiO2 gas sensors. The ammonia-sensing mechanisms of the Sn-TiO2@rGO/CNT gas sensor were proposed based on the formation of p-n heterojunctions of p-type rGO/CNT and n-type Sn-TiO2 nanoparticles via a low-temperature oxidizing reaction process.

| S-EPMC6796937 | biostudies-literature