Aggregation Of TiO2 Nanoparticles Research Articles

Effects of aggregation and settling of photoactive TiO2 nanoparticles on Microcystis aeruginosa and extracellular matters release

Owing to their diverse applications, TiO2-nanoparticles have been extensively discharged into the aquatic environment, posing serious threats to aquatic life and human health. Meanwhile, the aquatic organisms such as cyanobacteria affect the mobility and fate of the nanoparticles, in turn, these aquatic organisms also may be influenced by the nanoparticles, and which further elicits more hazard to ecosystem. In this study, the different concentration of TiO2 nanoparticles were added into the algal solution to observe the status of TiO2 nanoparticles and assess their influences, especially for photocatalytic toxicity on algal growth. The results demonstrated that algal cells and extracellular polymeric substances (EPS) simultaneously affected the TiO2 aggregation and settling in algae culture. In addition, TiO2 NPs inhibited the growth of algal cells through the multiple effects on the light adsorption, photosynthetic activity, oxidative stress and lipid peroxidation. Particularly, the reactive oxygen species generated by photoactive TiO2 NPs caused the changes of EPS and microcystin-LR (MC-LR) release, and these extracellular matters were crucial intermediate to the state of TiO2 NPs and algal cells growth. This study will not only be significant for understanding TiO2 behavior in the real aquatic environment but also be helpful for exploring the effects of TiO2 nanoparticles on cyanobacteria, especially for the released extracellular matters.

Synthesis and stabilities of Fe, Ni and Zn oxide incorporated colloidal TiO2

Owing to the unique physical and chemical characteristics of nanoparticles (NPs), their use in the manufacturing of commercial products is on the rise. The future will see an increasing quantity of NPs being discharged into our surroundings. This is precisely why it is important to understand their stability under changing conditions. This research examined the role of added Fe (III), Ni (II) and Zn (II) on the formation and stabilities of aqueous colloids of TiO2 particles. To the best of our knowledge, this is the first attempt to investigate the stability of lab synthesized composite NPs. The study confirmed that both the stability and environmental fate of metal oxide and mixed metal oxide NPs depends on the composition of aqueous environment. This can add more to the general understanding of NPs while paving way for exploring the stability and environmental fate of various mixed metal oxide/composites NPs as previous studies explored only commercially prepared plain NPs. TiO2 and TiO2-Fe2O3, TiO2-NiO, and TiO2-ZnO were synthesized following reported methods. Different characterization techniques including transmission electron microscope (TEM), x-rays diffraction (XRD), energy dispersive X-ray (EDX) analysis, and dynamic light scattering (DLS) were used to confirm the surface morphology, phase, elemental composition, and hydrodynamic (Dh) size of synthesized TiO2 particles. As-synthesized TiO2 and its various forms (TiO2-Fe2O3, TiO2-NiO, and TiO2-ZnO) showed rapid aggregation behavior in solutions, which is a sign of less or no threat to human health and the environment. Among the synthesized composites, TiO2-Fe2O3 showed the highest stability across all the methods utilized in this research. For all the approaches employed in dispersing aggregates of TiO2 NPs and their composites in solution, homogenization method displayed the highest efficiency. Moreover, the addition of an electrolyte i.e., KCl into the particle suspensions has affected the ionic strength of these suspensions resulting in an increased aggregation due to the shifting of ions-particles equilibrium. Thus, the formation of composites on TiO2 can govern both the stability and environmental fate of TiO2 particles under various aqueous environments.

Development of quantitative structure activity relationships (QSARs) for predicting the aggregation of TiO2 nanoparticles under favorable conditions

This study developed multi-linear regression (MLR) quantitative structure-activity relationships (QSARs) to predict n-TiO2 aggregation in the presence of high concentrations of representative emerging organic contaminants (EOCs), which presented favorable conditions to interaction with n-TiO2. The largest diameter change (Δ 517 nm at 0 h and Δ 1164 nm at 12 h) of n-TiO2 was observed by estrone, while the smallest diameter change (Δ −114 nm at 0 h and – 4 nm at 12 h) was observed by lincomycin during experimental periods. In addition, the zeta potential changes of n-TiO2 were observed that the biggest changes were observed by 17β-estradiol (−1.3 mV) and alachlor (−10.02 mV) at 0 h, while 17β-estradiol (−1.31 mV) and pendimethalin (−11.4 mV) showed the biggest changes at 12 h comparing to control. These changes of n-TiO2 diameter and zeta potential may implicate the effects of unique physico-chemical properties of each EOC on the surface modification of n-TiO2. Based on the interaction results, this study investigated the QSARs between n-TiO2 aggregation and physico-chemical descriptors of EOCs with 7 representative descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., # of HBD) for predicting n-TiO2 aggregation rate kinetics at 0 h and 12 h by applying MATLAB statistical methods (model 1 - fitlm and model 2 - stepwiselm). In a model 1, QSARs showed the good coefficients of determination (R2 = 0.92) at 0 h and (R2 = 0.87) at 12 h with 7 descriptors. In a model 2, QSARs showed the goodness of fit of a model (R2 = 0.9998) with 8 descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., #HBD, pKa⋅#H bond donors) at 0 h, while QSARs showed the coefficients of determination (R2 = 0.68) with 2 descriptors (pKa, M.V.) at 12 h. Particularly, we observed that some descriptors of EOCs such as pKa and # of HBD having polarity have more influenced on the n-TiO2 aggregation rate kinetics. Our developed QSARs demonstrated that the 7 descriptors of EOCs were significantly effective descriptors for predicting n-TiO2 aggregation rate kinetics in favorable conditions, which may implicate the complexity interactions between heterogeneous surfaces of n-TiO2 and physico-chemical properties of EOCs.

Impact of aggregation of TiO2 nanoparticles on the pulmonary response

Impact of aggregation of TiO2 nanoparticles on the pulmonary response

Core-Shell Composite MIL-101(Cr)@TiO2 for Organic Dye Pollutants and Vehicle Exhaust.

MIL-101(Cr)@TiO2 core-shell composite material was synthesized via the hydrothermal method, where MIL-101(Cr) served as the core and TiO2 acted as the shell. SEM results revealed that the metal-organic framework core effectively prevented the aggregation of TiO2 nanoparticles and facilitated their dispersion. Characterization techniques such as XRD, XPS, and TGA were utilized to confirm the successful loading of TiO2 onto MIL-101(Cr) and its excellent thermal stability. MIL-101(Cr)@TiO2 was employed in photocatalytic degradation of dye pollutants and vehicle exhaust, and the potential degradation mechanisms were investigated in detail. The results showed that MIL-101(Cr)@TiO2 exhibited excellent photocatalytic degradation performance towards dye pollutants, with degradation efficiencies of 91.7% and 67.8% achieved for MB and RhB, respectively, under visible light irradiation for 90 min. Furthermore, the photocatalytic degradation of automobile exhaust revealed that the MIL-101(Cr)@TiO2 composite material also exhibited degradation effects on NOx, CO, and HC. The degradation efficiency for NO reached 24.2%, indicating its broader applicability.

Enhanced lubrication by core-shell TiO2 nanoparticles modified with PEG-400

PurposeThe purpose of this paper is to enhance the characteristics of TiO2 nanoparticles (NPs). Because these NPs stick together easily and are difficult to distribute evenly, they cannot be used extensively in lubricating oils. Altering TiO2 was recommended as an alternate way for making NPs simpler to disperse.Design/methodology/approachThrough dielectric barrier discharge plasma (DBDP)-assisted ball mill diagnostics and modeling of molecular dynamics, TiO2@PEG-400 NPs were produced using the DBDP-assisted ball mill. The NPs’ microstructure was examined using FESEM, TEM, XRD, FT-IR and TG-DSC. Using the CFT-1 reciprocating friction tester, the tribological properties of TiO2@PEG-400 NPs as base oil additives were studied. EDS and XPS were used to examine the surface wear of the friction pair.FindingsTribological properties of the modified NPs are vastly superior to those of the original NPs, and the lipophilicity value of TiO2 NPs was improved by 200%. It was determined through tribological testing that TiO2@PEG-400’s exceptional performance might be attributable to a chemical reaction film made up of TiO2, Fe2O3, iron oxide and other organic chemicals.Originality/valueThis work describes an approach for preventing the aggregation of TiO2 NPs by coating their surface with PEG-400. In addition, the prepared NPs can enhance the tribological performance of lubricating oil. This low-cost, high-performance lubricant additive has tremendous promise for usage in marine engines to minimize operating costs while preserving navigational safety.

Tuning TiO2 Porosity of Multilayered Photoanode Towards Enhanced Performance of Dye Sensitized Solar Cell

In this paper, we prepared Titanium Dioxide (TiO2) based dye sensitized solar cells (DSSC). Downscaling of commercial TiO2 powder have been achieved by systematic ball milling carried out using home-made ball milling device. Thin films were prepared and samples were characterized by XRD, SEM, UV-Vis and I-V. The main objective of this work is to prepare TiO2 based (DSSC) using N3 dye and study the effect of the TiO2 grain size inside the photoanode layer on the efficiency of the solar cell. UV-vis study of nanometer sized TiO2 particles showed that the energy gab has shifted towards the lower wavelength in electromagnetic spectrum (blue shift), and then optical band gap is an indirect and allowed transition. Energy gap calculations of related grain size of showed quantum confinement effect. A sophisticated strategy for TiO2 films consisting of tailoring monolayer, bilayer and trilayer of mixed multisized nanoparticles were adopted and investigated as DSSC electrodes. Our results showed that the dye sensitized solar cells can be substantially altered due to the designs and the particle size distributions of the TiO2 photoelectrode. The maximum efficiency of 0.5% was reached by TiO2 photoelectrode designed as a trilayer with a particles of wide size distribution from about 12 to 340 nm in the middle layer. The approach of light scattering in submicrometer‐sized TiO2 nanoparticles aggregates was adopted in order to interpret the enhancement of our DSSC efficiency over extending the length transported by electromagnetic wave hence to promote the light acquiring efficiency of photoelectrode thin film. The relatively larger particle sizes afford the TiO2 films with both better packing and an increased capability for scattering of the incident electromagnetic wave, and hence improves our DSSC efficiency.

High photocatalytic activity of spent coffee grounds derived activated carbon-supported Ag/TiO2 catalyst for degradation of organic dyes and antibiotics

Titanium dioxide (TiO2) has been considered as a promising photocatalyst for degrading organic pollutants due to its stability, low energy consumption and non-toxicity. Nevertheless, the aggregation tendency, relatively wide band gap and easy recombination of electron-hole pairs confine the photocatalytic activity and practical applications of TiO2 nanoparticles. Herein, a novel Ag/TiO2/carbon skeleton derived from spent coffee grounds (CSCG) ternary photocatalyst was developed by in-situ growth of TiO2 and Ag nanoparticles onto 3D activated CSCG via a hydrothermal process and subsequent photodeposition method. The utilization of excellent conductive CSCG as catalytic carrier can not only alleviate the aggregation of TiO2 nanoparticles, but also suppress the recombination of photogenerated electron hole pairs. Besides, the surface plasmon resonance (SPR) effect of Ag reduces the band gap of the material and widens light-responsive region, thereby endowing Ag/TiO2/CSCG photocatalyst with enhanced photocatalytic degradability for organic pollutants. The as-prepared photocatalyst exhibits high degradation effects on dyes and antibiotics, such as degradation rate of 96.2% for methylene blue (MB), methyl orange (MO: 94%), tetracycline (TC: 99%), and norfloxacin (NOF: 96%). In addition, the hybrid photocatalyst displays up to 91% degradation efficiency of MB after four cycles. This work presents an innovative perspective to construct TiO2-based hybrid photocatalyst for boosting photocatalytic performance of wastewater treatment and environmental remediation.

Sedimentation Process of TiO2 Nanoparticles in Aqueous Solution

TiO2 nanoparticles, a semiconductor photocatalyst is widely used in various applications especially for water treatment. The common problems for the application are separating the nanoparticles from the water body and recovering it to be reused. This research was conducted to investigate the aggregation and sedimentation properties of TiO2 nanoparticles via chemical addition. The experiment was carried out for 5 hours by varying the pH, ionic strength, and the addition of organic matter such as rhodamine B, methylene orange, and humic acid. The results indicate that pH and ionic strength greatly affect the TiO2 sedimentation process. Sedimentation can be formed properly when the solution is at pH 1 and 14, this happens because pH is close to the isoelectric point. Meanwhile, ionic strength with a concentration of 0.1 M gave the most optimal results in TiO2 sedimentation. In the presence of ionic strength with the appropriate concentration, the thickness of the electrical double layer particles can be reduced so the attractive force increases and sedimentation occur. Meanwhile, in the presence of organic matter, rhodamine B, methylene orange, and humic acid did not significantly affect the formation of TiO2 sedimentation.Keywords: titanium dioxide, sedimentation, ionic strength, isoelectric point, water treatment

Sedimentation Process of TiO2 Nanoparticles in Aqueous Solution

TiO2 nanoparticles, a semiconductor photocatalyst is widely used in various applications especially for water treatment. The common problems for the application are separating the nanoparticles from the water body and recovering it to be reused. This research was conducted to investigate the aggregation and sedimentation properties of TiO2 nanoparticles via chemical addition. The experiment was carried out for 5 hours by varying the pH, ionic strength, and the addition of organic matter such as rhodamine B, methylene orange, and humic acid. The results indicate that pH and ionic strength greatly affect the TiO2 sedimentation process. Sedimentation can be formed properly when the solution is at pH 1 and 14, this happens because pH is close to the isoelectric point. Meanwhile, ionic strength with a concentration of 0.1 M gave the most optimal results in TiO2 sedimentation. In the presence of ionic strength with the appropriate concentration, the thickness of the electrical double layer particles can be reduced so the attractive force increases and sedimentation occur. Meanwhile, in the presence of organic matter, rhodamine B, methylene orange, and humic acid did not significantly affect the formation of TiO2 sedimentation.Keywords: titanium dioxide, sedimentation, ionic strength, isoelectric point, water treatment

Sedimentation Process of TiO2 Nanoparticles in Aqueous Solution

TiO2 nanoparticles, a semiconductor photocatalyst is widely used in various applications especially for water treatment. The common problems for the application are separating the nanoparticles from the water body and recovering it to be reused. This research was conducted to investigate the aggregation and sedimentation properties of TiO2 nanoparticles via chemical addition. The experiment was carried out for 5 hours by varying the pH, ionic strength, and the addition of organic matter such as rhodamine B, methylene orange, and humic acid. The results indicate that pH and ionic strength greatly affect the TiO2 sedimentation process. Sedimentation can be formed properly when the solution is at pH 1 and 14, this happens because pH is close to the isoelectric point. Meanwhile, ionic strength with a concentration of 0.1 M gave the most optimal results in TiO2 sedimentation. In the presence of ionic strength with the appropriate concentration, the thickness of the electrical double layer particles can be reduced so the attractive force increases and sedimentation occur. Meanwhile, in the presence of organic matter, rhodamine B, methylene orange, and humic acid did not significantly affect the formation of TiO2 sedimentation.Keywords: titanium dioxide, sedimentation, ionic strength, isoelectric point, water treatment

Construction of TiO2 microsphere through different titanium precursors via a green pathway

TiO2 microspheres (TMCS) with superior dispersity and uniform particle size (size distribution vary from 1 µm to 3 µm) were synthesized by using of different titanium precursors through a sol–gel method. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) were employed to study the morphology and microstructure. Moreover, by Brunauer-Emmett-Teller (BET) test, the specific surface area of TMCS were about 200 m2/g. In addition, Raman spectroscopy (Raman), X-ray diffraction (XRD) and X–ray photo-electron spectroscopy (XPS) were applied to investigate the phase composition and existing state of TMCS. Furthermore, its photocatalytic activity was estimated by observing the degradation efficiency of Rhodamine (RhB). Remarkably, the degradation efficiency is 98 % after 30 min and the photocatalytic degradation rate remained almost unchanged in five successive cycles, indicating that TMCS were stable and suitable for removing RhB in water. Finally, the probable formation mechanism of TMCS was studied. The spontaneous aggregation of TiO2 nanoparticles lead to the formation of TMCS which would be promoted to combine with others to form mesoporous TMCS by temperature. Therefore, this work provides an encouraging pathway for controlling the morphology of TiO2 and showing potential application in wastewater treatment.

Reactivity of Hydrogen-Related Electron Centers in Powders, Layers, and Electrodes Consisting of Anatase TiO2 Nanocrystal Aggregates.

Anatase TiO2 nanoparticle aggregates were used as model systems for studying at different water activities the reactivity of electron centers at semiconductor surfaces. The investigated surface conditions evolve from a solid/vacuum interface to a solid/bulk electrolyte interface. Hydrogen-related electron centers were generated either chemically—upon sample exposure to atomic hydrogen at the semiconductor/gas interface—or electrochemically—upon bias-induced charge accumulation at the semiconductor/electrolyte interface. Based on their corresponding spectroscopic and electrochemical fingerprints, we investigated the reactivity of hydrogen-related electron centers as a function of the interfacial condition and at different levels of complexity, that is, (i) for dehydrated and (partially) dehydroxylated oxide surfaces, (ii) for oxide surfaces covered by a thin film of interfacial water, and (iii) for oxide surfaces in contact with a 0.1 M HClO4 aqueous solution. Visible (Vis) and infrared (IR) spectroscopy evidence a chemical equilibrium between hydrogen atoms in the gas phase and—following their dissociation—electron/proton centers in the oxide. The excess electrons are either localized forming (Vis-active) Ti3+ centers or delocalized as (IR-active) free conduction band electrons. The addition of molecular oxygen to chemically reduced anatase TiO2 nanoparticle aggregates leads to a quantitative quenching of Ti3+ centers, while a fraction of ∼10% of hydrogen-derived conduction band electrons remains in the oxide pointing to a persistent hydrogen doping of the semiconductor. Neither trapped electrons (i.e., Ti3+ centers) nor conduction band electrons react with water or its adsorption products at the oxide surface. However, the presence of an interfacial water layer does not impede the electron transfer to molecular oxygen. At the semiconductor/electrolyte interface, inactivity of trapped electrons with regard to water reduction and electron transfer to oxygen were evidenced by cyclic voltammetry.

Gum ghatti-alginate hybrid bead derived titania spheres for deep removal of toxic dye Remazol Brilliant Violet from aqueous solutions

Mesoporous titania spheres was achieved using titanium (IV) isopropoxide as precursor and alginate-gum ghatti composite beads as structure directing agent via the low-temperature sol-gel synthesis method.These polysaccharides are multi-functional in nature & exhibiting secondary interactions in solution to accept new rheological and textural properties. The mixed beads of adequate mechanical strength could be obtained by keeping the ratio>1:1 for alginate to gum ghatti. The synthesized spheres were extensively characterized using FTIR, BET, SEM, TEM, and XRD. TEM study revealed that hollow titania spheres (HSAG3) are formed through the aggregationof TiO2 nanoparticles. Adsorption activity of titania spheres was investigated by employing Remazol Brilliant Violet (RBV) dye as the model reactive azo dye compounds. The dye adsorption mechanism was investigated indepthly using various kinetics models. Adsorption data found to be well expressed through pseudo second-order kinetics model. Further, data was also interpreted through Boyd model and the obtained diffusion constant value found to be in the order of 10−17 cm2/m, suggesting pore diffusion mechanism plays significant role in governing overall rate of the sorption process. The adsorption equilibrium data better conformed with the Langmuir isotherm which indicates surface homogeneity of the spheres for dye adsorption. Recycling study prompted that the adsorbent can be employed successively for 5 consecutive times without observing any significant loss in adsorption capacity. Overall the study revealed that the titania spheres can be serve as a promising adsorbent specifically for the removal of Remazol Brilliant Violet dye and other reactive anionic azo dyes in general.

A Facile Urea-Assisted Thermal Decomposition Process of TiO2 Nanoparticles and Their Photocatalytic Activity

In the present work, we have reported a facile and large-scale synthesis of TiO2 nanoparticles (NPs) through urea-assisted thermal decomposition of titanium oxysulphate. We have successfully synthesized TiO2 NPs by using this effective route with different weight ratios of titanium oxysulphate: urea. The structures and properties of TiO2 NPs were confirmed by scanning electron microscope) (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy (UV-vis), and photoluminescence (Pl) techniques. XRD demonstrated that TiO2 NPs holds of anatase crystal phase with crystallizing size 14–19 nm even after heating at 600 °C. TGA, SEM, and TEM images reveal urea’s role, which controls the size, morphology, and aggregation of TiO2 NPs during the thermal decomposition. These TiO2 NPs were employed for photodegradation of Methyl Orange (MO) in the presence of ultraviolet (UV) radiation. An interesting find was that the TiO2 NPs exhibited better photocatalytic activity and excellent recycling stability over several photodegradation cycles. Furthermore, the present method has a great perspective to be used as an efficient method for large-scale synthesis of TiO2 NPs.

Effects of chlorella extracellular polymeric substances on the aggregation and stability of TiO2 nanoparticles as electrolytes

Effects of chlorella extracellular polymeric substances on the aggregation and stability of TiO2 nanoparticles as electrolytes

Preparation of TiO2 Nanoparticle Aggregates and Capsules by the ‘Two-Emulsion Method’

TiO2-based materials are of great practical interest in several technological areas. Both the size and the morphology of the TiO2 particles are of critical importance for their applications. The current study explores the effect of several factors on the outcome of the TiO2 particle synthesis via the so-called ‘two-emulsion method’. In this technique, two water-in-oil emulsions—each of them containing different reactant in the dispersed water drops—are mixed under well controlled conditions. Upon such mixing, partial coalescence of the water drops from the two emulsions leads to mixing of the drop content, with chemical reaction occurring within the drops, and to synthesis of Ti(OH)4 particles. Afterwards, the latter are transformed by emulsion heating into TiO2 particles and aggregates of predominantly anatase structure. Our results show that—depending on the precursor and surfactant concentrations, oil viscosity, emulsification time, and mixing speed—the obtained nanoparticles could aggregate either on the drop surface, forming capsules with a very smooth surface, or inside the water droplets, thus leading to hierarchically structured aggregates of micrometer size. The spherical smooth capsules are constructed of very small monodisperse TiO2 nanoparticles with size below 5 nm. The hierarchical bulk aggregates, on the other hand, are formed from bigger primary particles of sub-micrometer size. The obtained results show that one can obtain various TiO2 structures by controlling the conditions during the emulsion preparation and mixing

Investigation of the TiO2 nanoparticles aggregation with high light harvesting for high-efficiency dye-sensitized solar cells

The TiO2 nanoparticles aggregation (TNA) was synthesized by a novel one-step hydrothermal method in this work. And for the first time we prepared a kind of jelly pastes of TNA used as photoanode for high-efficiency dye-sensitized solar cells (DSSCs). The prepared TNA provides larger specific surface area of 79.34 m2 g−1 compared with P25 nanoparticles (49.25 m2 g−1), which is beneficial of absorbing more dye molecules and contributes to high current densities. Moreover, the high scattering effect of TNA caused a strong absorption in the visible-light range increasing the number of excited charges and reducing the energy loss. The effect of various concentrations of TNA pastes for DSSCs was studied to explore the superiority of concentrated TNA pastes. The result shows the DSSC based on high-concentration pastes and double-layer film achieved the best power conversion efficiency (PCE) of 8.34 % corresponding the current density of 17.97 mA cm-2.

Titanium decorated iron oxide (Ti@Fe2O3) regulates the proliferation of bovine muscle satellite cells through oxidative stress

In the present study, the titanium decorated iron oxide (Ti@Fe2O3) nanocomposites are synthesized using the chemical method. The as-prepared nanocomposite was characterized for successful formulation and the elemental spectra showed the composition of Fe (44%), Ti (0.71%) and O (55%) is confirmed the homogenous distribution. Crystallographic spectra depict the strong peaks corresponding to the of TiO2 and Fe2O3 nanoparticles planes with minor shift variation due to the formulation of Ti on the surface of Fe2O3 nanoparticles and it is also confirmed with SAED analysis. The X-ray photoelectron spectroscopy (XPS) analysis of Ti@Fe2O3) nanocomposite confirms the existence of elements such as Fe, O and Ti. Further, the morphology of the composite showed the well-defined encapsulation and aggregation of TiO2 nanoparticles on the surface of Fe2O3 nanoparticles. Further, the TiO2 nanoparticles showed less cytotoxic activity against bovine satellite cells, as well the nanocomposite increased the growth of bovine satellite cells comparing with control cells. Further, the morphological analysis showed the significant changes in TiO2 nanoparticles treated cells and the nanocomposite induces the myotube formation due to the increased ROS level in bovine satellite cells. Moreover, the nanocomposite regulates the expression of genes IGF-1, TGF-β, MSTN, CASP3, CASP2 and proteins such as CALP1, CALP2, MyoD, MyoG which are responsible for the growth, proliferation, and differentiation of satellite cells. Together, the prepared Ti@Fe2O3 nanocomposites afford additional support for the applications of nanomaterials in skeletal muscle repair and tissue regeneration engineering.

WEAR BEHAVIOR OF HYBRID COMPOSITE REINFORCED WITH TITANIUM DIOXIDE NANOPARTICLES

The aim of the present study is to investigate the influence of polymerization times, normal loads and titanium dioxide nanoparticles content on the wear of hybrid composite resin reinforced with titanium dioxide (TiO2) nanoparticle. The materials used are hybrid composite resin and titanium dioxide nanoparticles (TiO2nanoparticles). Four groups of composite resin samples are prepared; one as received and three groups reinforced with TiO2nanoparticles in contents of 0.1, 0.2 and 0.3 wt. %. Hybrid composites resin is manually mixed with TiO2 nanoparticles. The resulting blend is packed into plastic cylindrical bars. The samples are then cured from both sides for 10, 20, 40, 60 and 80 seconds using a visible light curing unit. To determine the wear, all samples are tested with two-body abrasion, reciprocating sliding apparatus at room temperature. The test conditions are; sliding velocity= 60 strokes/min, load= 6, 8, 10, 12 and 14 N, time= 60 seconds. Results show that the wear decreases with the increase of polymerization time at all normal loads. Results showed also that wear depends on the normal load. The wear initially decreased and reached a minimum at a concentration of 0.1 wt. % TiO2 nanoparticles, above 0.1 wt. % TiO2 nanoparticles, the aggregation of TiO2 nanoparticles led to increase of the wear. The present study suggests that in order to minimize wear, it is important to use relatively higher polymerization time, lower TiO2content and lower force of chewing.