Titania Particles Research Articles

Surface morphology and Rietveld refinement characterisation of aluminium/titania nanocomposite produced by atmospheric plasma spraying and accumulative roll bonding

ABSTRACT In this study, the nano-sized Titania (TiO2) particles were coated on an aluminum (Al) matrix using the atmosphere spraying method, and then the Al-TiO2 nanocomposite was fabricated by the accumulative roll bonding (ARB) process. The surface morphology evaluation by the field emission scanning electron microscopy (FESEM) revealed that TiO2 nanoparticles are uniformly spread and the amount of TiO2 nanoparticles decreased on the surface during the ARB process energy dispersive spectroscopy (EDS) mapping and X-ray diffraction (XRD) analysis demonstrated a decrease in the TiO2 phase while an increase in the Al phase in further cycles of the ARB process. Based on the atomic force microscopy (AFM) micrograph, the thicknesses of TiO2 particle clusters decreased from 1.26 μm to 238 nm by increasing the number of ARB cycles. The surface roughness values measured by the profilometer showed that the pressure of rolling has been an effect on reducing roughness to 96 micrometers, up to seven cycles of the ARB process. to calculate the Al crystallite size, TiO2 nanoparticles size, micro-strains and dislocation densities, the Rietveld refinement indicated that the increasing micro-strains and dislocation densities have led to reducing the Al crystallites and TiO2 particle clusters size to 234 and 40 nm, respectively.

Electrochemical Corrosion Behavior of Ni–TiO2 Composite Coatings Electrodeposited from a Deep Eutectic Solvent-Based Electrolyte

The need to develop new electrochemical energy storage and conversion devices requires the creation of new, available, low-cost and high-performance electrocatalytic materials, which can be produced as coatings by electrodeposition technique. The electrodeposited composite coatings based on nickel seem to be very promising in this context. We studied the corrosion resistance of electrocatalytic Ni–TiO2 composite coatings fabricated by electrodeposition method using a plating solution based on deep eutectic solvents, a new environmentally friendly and affordable type of room-temperature ionic liquids. We investigated the corrosion behavior of Ni and Ni–TiO2 coatings (5 and 10 wt.% of TiO2) in a 3% NaCl aqueous solution as a corrosive medium. The corrosion parameters were determined by linear voltammetry and electrochemical impedance spectroscopy. It was established that the inclusion of titania particles in the Ni matrix and an increase in their content in the coating leads to a shift in corrosion potential towards positive values, a decrease in corrosion current density and an increase in polarization resistance. The observed effects of improving the corrosion resistance of coatings are associated with the barrier action of particles of the dispersed phase and the formation of corrosion microcells contributing to the inhibition of local corrosion.

Efficient Method for α-TiP Synthesis using Alkaline Decomposition Pretreatment of Ilmenite Natural Beach Sand

The layered, acidic compound; α-TiP is widely popularized as a sorbent material for heavy metal removal from wastewater, as catalysts for biomass conversion and as an intermediate to produce high purity titanium dioxide particles. One of the conventional route for its synthesis is to react ilmenite with orthophosphoric acid under reflux conditions. However, the major drawback of this method is that the titanium recovery is only 35 wt. % and about 10 wt. % of the initial ilmenite remain unreacted as the residue. The conversion of ilmenite into an easily acid digestible compound could be attained via alkaline roasting. The objective of this research was to increase the yield of α-TiP from ilmenite using an additional alkaline roasting pre-treatment step to the acid leaching. Potassium hydroxide was selected for the alkaline roasting step since it is regarded to be an environmentally benign chemical. The pre-treatment of ilmenite with a 1:4 molar ratio of KOH to ilmenite at 700 C generated potassium iron oxides and potassium titanium oxides as intermediate compounds which were then washed with distilled water, filtered and dried at 100 C for 24 hours. The solid compound was reacted with orthophosphoric acid with a solid to liquid ratio of 1/8 under reflux conditions for 4 hours. Then the remaining acid leachate was decanted and the white precipitate from the leach liquor was filtered, washed and dried at 100 C for 24 hours. The obtained powder was characterized using X-Ray Diffraction (XRD) analysis, X-Ray Fluorescence (XRF) spectroscopy, FTIR spectroscopy and Raman spectrophotometry and was confirmed to be α-TiP. The parameters; the effect of KOH/ilmenite ore molar ratio, calcination temperature, solid to liquid ratio in the acid leaching step, acid leaching reflux time on the titanium recovery were fine tuned. This research concluded the possibility of increasing the titanium extraction. Therefore the research concludes the increment of α-TiP yield after the pre-treatment step using KOH.
 Keywords: Ilmenite, Titanium phosphate, Alkaline roasting, Alkaline pretreatment

Electrospun Membrane with Ultrafine Fibers for Oil/Water Separation Application

Environmental pollution has become an urgent concern for both nature and human beings because of oily wastewater spills from industries and household appliances. Therefore, the filtration of industrial oily wastewater is now a major problem in the present world. Many types of experiments are being conducted to find a solution for this issue, and researchers are still looking for a cheaper and better solution. A promising response to this issue can be membrane-interfaced oil-water filtration. And the application of Electrospun membranes can successfully solve this matter. It is found that Polyvinylidene Fluoride-based membranes are being used for this process because of their resistance to chemicals and good mechanical strength. Also, Titanium Dioxide particles are a suitable choice because of their non-hazardous properties and solubility with polymer solutions. In this study, Titanium Dioxide nanoparticles were first synthesized by modifying their pH, and then Electrospun Nanofibrous membranes were produced by adding those modified particles with Polyvinylidene Fluoride. A unique preparation method was used to decrease the particle diameter with alkaline agents, which also results in decreased fiber diameter of membranes. The produced membranes showed improved oleophilic properties and hydrophobicity. Finally, membranes were applied and can be associated with the progress of Oil/Water separation purposes, which also can sustain the recycling process of hazardous chemicals and ensure the contribution to a safe environment.

Fabrication of Surface Metal Matrix composite of AA7075 using Friction Stir Processing

Friction stir processing (FSP), a process, derived from the friction stir welding (FSW) process, is an emerging novel, green and energy efficient processing technique to fabricate surface composite. In the present investigation, the FSP technique has been used for the fabrication of surface composites, usingAluminium Alloy 7075 as parent metal and Titanium Dioxide and Silicon Carbide powder particles as reinforcement. Aluminium Alloy 7075 has been selected as the matrix phase, as being widely used by the automotive and aerospace application and has the highest strength among all commercial Al alloys. In present work details about the fabrication of surface composites using various reinforcement combinations like AA7075-TiO2, AA7075-andAA7075-SiC,TiO2+SiC at constant tool rotation, tool travel speed and number of passes have been discussed. The same being intended to improve hardness. It is observed that the average hardness of friction stir processed surface composite was 4 higher than that of parent metal.

Fabrication of Surface Metal Matrix Composite of AA7075 using Friction Stir Processing

Friction stir processing (FSP), derived from the friction stir welding (FSW) process, is an emerging novel, green and energy-efficient processing technique to fabricate surface composite. The FSP technique has been used in the present investigation to fabricate surface composites, using Aluminium Alloy 7075 as parent metal and Titanium Dioxide and Silicon Carbide powder particles as reinforcement. Aluminium Alloy 7075 has been selected as the matrix phase, as being widely used by the automotive and aerospace application and has the highest strength among all commercial Al alloys. The present work details the fabrication of surface composites using various reinforcement combinations like AA7075- TiO2, AA7075- and AA7075- SiC, TiO2+SiC at constant tool rotation, tool travel speed and the number of passes have been discussed. The same being intended to improve hardness and thereby wear resistance. The fabricated surface composites are examined for microstructure using an image analyzer and found friction stir processed zone with fine microstructure than the base material. It is also observed that the average hardness of friction stir processed surface composite was higher than that of parent metal. Wear Resistance is found to be improved compared to the parent metal. It is found that Tensile strength is also enhanced than the base material.

Variation behavior of organic compounds in melamine-urea-formaldehyde impregnated bond paper in different pyrolysis stages

Melamine-urea-formaldehyde impregnated bond paper (MUF) is widely used as panel coating and decorative raw paper. Inappropriate treatment of MUF may lead to environmental pollution. In this study, routine MUF and MUF treated with additional titanium (MUF-T) were subjected to fast pyrolysis, and the product properties at different temperatures were investigated. The pyrolysis temperature was selected considering the reaction stages determined by Gaussian curve-fitting on thermogravimetric analysis curves. It was found that the presence of additional titanium changed the decomposition order of the organic components at 220 °C. Urea-formaldehyde in MUF could be decomposed at 220 °C, which had little effect on other components (melamine and cellulose). However, in terms of MUF-T, the decomposition temperature of urea-formaldehyde was postponed to 244 °C, which means that the pyrolysis strategy needs to choose a temperature higher than 244 °C. The volatiles in MUF-T are more easily converted to bio-gas or bio-oil than those in MUF. However, only CH4 was observed in the bio-gas generated of MUF-T at 220 °C, indicating that titanium did not catalyze the fracture of oxygen-containing functional groups at low temperatures. Titanium condensed at 550 °C, and the utilization of bio-char may face a problem of titanium particle shedding.

Dietary titanium dioxide particles (E171) promote diet-induced atherosclerosis through reprogramming gut microbiota-mediated choline metabolism in APOE-/- mice

Food-grade titanium dioxide (E171) has been reported to induce changes in some intestinal metabolites related to development of atherosclerosis (AS). However, little is known about the effects of chronic dietary intake of E171 on AS development, particularly in AS-prone populations with high-choline western diet (HCD). Herein, we disclosed that E171 obviously exacerbated HCD-induced AS through increasing production of trimethylamine (TMA) and pro-atherogenic trimethylamine-N-oxide (TMAO) via remodeling gut microbiota structure in APOE-/- mice. Oral administration of 40 mg/kg E171 daily for 4 months significantly increased the atherosclerotic lesion area, especially in the HCD group. Mechanistic studies revealed that E171 induced much more TMAO production by increasing the gut microbial expression of choline TMA lyases (CutC/D), which converted dietary choline to TMA by a glycyl radical reaction. The 16S rDNA sequencing analysis demonstrated that bacterial strains expressing CutC/D were enriched by E171 in HCD-fed mice. In contrast, gut microbiota depletion eliminated the impact of E171 on choline/TMA/TMAO pathway and AS progression, indicating gut flora shifts were responsible for the exacerbation effects of E171 ingestion on HCD-induced AS. All the results emphasized the alarming role of E171 on AS progression and stated the importance of reevaluating the impact of food additives on the development of chronic diseases.

LY450139 Inhibited Ti-Particle-Induced Bone Dissolution via Suppressing Notch and NF-κB Signaling Pathways

Aseptic loosening of the prosthesis caused by wear-particle-induced osteolysis is a long-term complication and one of the most common reasons for the failure of joint implants. The primary cause of aseptic loosening of the prosthesis is overactive bone resorption caused by wear-particle-activated osteoclasts in both direct and indirect ways. Therefore, drugs that can inhibit differentiation and bone resorption of osteoclasts need investigation as a potential therapeutic strategy to prevent and treat peri-prosthetic osteolysis and thereby prolong the service life of the prosthesis. This study has verified the potential inhibitory effect of LY450139 on inflammatory osteolysis induced by titanium particles in a mice skull model. In addition, we found that LY450139 inhibited receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis, bone resorption, and podosomal actin belt formation in a dose-dependent manner without evidence of cytotoxicity in vitro. In addition, LY450139 significantly decreased the expression of osteoclast-specific markers, including TRAP, CTSK, V-ATPase d2, CTR, DC-STAMP, NFATc1, and the downstream target gene Hes1 in Notch signaling pathway. Further investigation of the molecular mechanism demonstrated that LY450139 inhibited the formation of osteoclasts via inhibition of the NF-κB and Notch signaling pathways. In summary, LY450139 inhibited the formation of RANKL-mediated osteoclasts via NF-κB and Notch signaling and inhibited Ti particle-induced inflammatory osteolysis in vivo. LY450139 is a potential targeted drug for the treatment of peri-prosthetic osteolysis and other osteolytic disease associated with overactive osteoclasts.

The Characterization of Titanium Particles Released from Bone-Level Titanium Dental Implants: Effect of the Size of Particles on the Ion Release and Cytotoxicity Behaviour

Many studies are being carried out on the particles released during the implantoplasty process in the machining of dental implants to remove bacterial biofilms. However, there are no studies on the release of particles produced by the insertion of bone-level dental implants due to the high compressive frictional loads between the rough titanium implant and the bone tissue. This paper aims to characterize the released particles and determine the release of titanium ions into the physiological environment and their cytocompatibility. For this purpose, 90 dental implants with a neck diameter of 4 mm and a torque of 22 Ncm were placed in 7 fresh cow ribs. The placement was carried out according to the established protocols. The implants had a roughness Ra of 1.92 μm. The arrangement of the particles in the bone tissue was studied by micro-CT, and no particle clusters were observed. The different granulometries of 5, 15, and 30 μm were obtained; the specific surface area was determined by laser diffraction; the topography was determined by scanning electron microcopy; and the particles were chemically analysed by X-ray energy microanalysis. The residual stresses of the particles were obtained by X-ray diffraction using the Bragg-Bentano configuration. The release of titanium ions to the physiological medium was performed using ICP-MS at 1, 3, 7, 14, and 21 days. The cytocompatibility of the particles with HFF-1 fibroblast and SAOS-2 osteoblast cultures was characterized. The results showed that the lowest specific surface area (0.2109 m2/g) corresponds to the particles larger than 30 μm being higher than 0.4969 and 0.4802 m2/g of those that are 5 and 15 μm, respectively, observing in all cases that the particles have irregular morphologies without contamination of the drills used in the surgery. The highest residual stresses were found for the small particles, −395 MPa for the 5 μm particles, and −369 for the 15 μm particles, and the lowest residual stresses were found for the 30 μm particles with values of −267 MPa. In all cases, the residual stresses were compressive. The lowest ion release was for the 30 μm samples, as they have the lowest specific surface area. Cytocompatibility studies showed that the particles are cytocompatible, but it is the smallest ones that are lower and very close to the 70% survival limit in both fibroblasts and osteoblasts.

Nucleation mechanisms of titanium oxide particles at high temperature based on cluster-assisted nucleation

The properties of functional particles are intrinsically linked to their nucleation process. However, for such particles at high temperature, it is difficult to observe their nucleation in real time, and so the corresponding properties are rarely well understood. In the reported study, the nucleation of titanium oxide particles was systematically investigated by means of both classical nucleation theory and first principles. In high-temperature experiments, three samples (T1-T3) with differing titanium content were processed into metallographic samples and subjected to electrolytic extraction for observations via scanning electron microscopy-energy dispersive spectroscopy, X-ray microdiffraction, and transmission electron microscopy. It was determined that the titanium oxide particles in the three samples were Ti2O3, Ti3O5, and TiO2. The nucleation rate and radius of these particles were calculated using classical nucleation theory, and the results were consistent with the experimental results for the Ti2O3 particles but not the Ti3O5 ones. The theoretical and experimental values for T1–T3 decreased in the order T1>T2>T3, and there were considerable differences of as much as an order of magnitude between some of the theoretical and experimental values. The size effect on the nucleation was analysed by constructing (Ti2O3)n, (Ti3O5)n, and (TiO2)n (n = 1–6) nanoclusters, and the thermodynamic properties of the nanoclusters and nano-sized titanium oxide particles were analysed. The thermodynamic properties of the titanium oxide particles estimated using density functional theory generally coincided with those determined experimentally. Based on cluster-assisted nucleation, four nucleation pathways for titanium oxide particles were summarized as follows: (i) [Ti]atom + [O]atom → (TiO2)n → (TiO2)5 → TiO2 particle or (TiO2)5-cluster core–shell nanoparticle → (TiO2)bulk, (ii) [Ti]atom + [O]atom → (Ti3O5)n → (Ti3O5)2 → Ti3O5 particle or (Ti3O5)2-cluster core–shell nanoparticle → (Ti3O5)bulk, (iii) [Ti]atom + [O]atom → (Ti2O3)n → (Ti2O3)3 → Ti2O3 particle or (Ti2O3)3-cluster core–shell nanoparticle → (Ti2O3)bulk, and (iv) [Ti]atom + [O]atom → (TiO2)n, (Ti3O5)n, (Ti2O3)n → (Ti2O3)3 → Ti2O3 particle or (Ti2O3)3-cluster core–shell nanoparticle → (Ti2O3)bulk.

Influence of electrochemically deposited TiO2 on the anti-weathering properties of heat-treated wood

ABSTRACT Ultraviolet light-induced discoloration is a noticeable issue when heat-treated wood is used outdoors. In this study, titanium dioxide (TiO2) particles were electrochemically deposited on the surface of heat-treated wood via a high-voltage electrostatic field (HVEF). Natural and artificial weathering tests were carried out to evaluate the anti-weathering properties after the electrochemical deposition. During HVEF treatment, Ti particles were triggered in the form of Ti4+. Ti4+ grafted with the hydroxyl groups of hemicellulose and lignin in the form of Ti–OH, and TiO2 was produced due to the oxidizing atmosphere generated by HVEF. TiO2 and Ti–OH played roles as UV absorbers, reducing degradation and discoloration of heat-treated wood. The photodegradation of lignin was alleviated effectively during both the artificial and natural weathering. The stability of wood color was remained. After the artificial weathering, the values of L*, a* and b* of the electrochemical depositied sample were 55, 10 and 25, respectively. The leaching amount of TiO2 after artificial or natural weathering was less than 6% or 40%, respectively determined by atomic absorption spectroscopy. The results suggest the feasibility of the electrochemical deposition of TiO2 for improving the anti-weathering properties of heat-treated wood and provide an effective strategy for industrial wood modification.

Unexpected high early failure rate of the Nexel total elbow arthroplasty.

BackgroundAseptic loosening, polyethylene wear, and mechanical failure have limited the use of total elbow arthroplasty (TEA) in physically demanding patients. Newer implant designs have been introduced to improve mechanical performance. The purpose of this study was to report the results obtained after implantation of the Nexel TEA.MethodsOver a 3-year period, 2 surgeons implanted a total of 35 consecutive Nexel primary TEAs. The average patient age was 65 years, and standard TEA indications were utilized. Elbows were evaluated for pain, motion, the Mayo Elbow Performance Score, complications, and reoperations.ResultsTwelve elbows underwent a revision surgery with removal of either a part of or all Nexel components at an average of 2.2 years. All revision surgeries performed at our institution revealed gross loosening of the component(s). Metallic debris and periprosthetic fractures were present in 45% and 50% of cases, respectively. Radiographic evaluation of existing components revealed humeral component loosening and periprosthetic fractures in 2 and 4 elbows, respectively. Overall, 17 of 35 (50%) elbows underwent reoperation, and 20 of 35 (60%) elbows sustained at least 1 postoperative complication.ConclusionPrimary TEA with implantation of this implant was associated with an unacceptably high rate of early implant loosening, periprosthetic fracture, and reoperation. We hypothesize that this early unexpected mechanical failure could be explained by both the utilization of a titanium-on-polyethylene bearing surface and a more posterior center of rotation causing premature anterior impingement with flexion leading to failure of the bonding interface, secondary titanium particle shedding, polyethylene wear, and osteolysis.

Oxygen-deficient titanium dioxide-loaded black phosphorus nanosheets for synergistic photothermal and sonodynamic cancer therapy.

Malignant tumors, particularly those located in deep tissues, have always been a grievous threat to human health. Sonodynamic therapy (SDT) has recently attracted great attention due to deep tissue penetration. However, the lack of effective sonosensitizers and the poor therapeutic efficacy severely limit their wider use. Herein, dual-functionalized black phosphorus nanosheets (BP@PEI-PEG, i.e., PPBP) integrating black oxygen-deficient titanium dioxide particles (B-TiO2) were successfully constructed (PPBP-B-TiO2) for synergistic photothermal (PTT)/sonodynamic therapy. In these nanocomposites, black titanium dioxide can enhance the separation of electrons (e-) and holes (h+) due to the oxygen-deficient structure and significantly improves the production of reactive oxygen species (ROS) for SDT, while the BP nanosheets endow the nanocomposites with a higher photothermal conversion capability for photothermal therapy (η=44.1%) which can prolong the blood circulation and improve the O2 supply. In vivo experiments prove that PPBP-B-TiO2 nanocomposites exhibited outstanding tumor inhibition efficacy and excellent biocompatibility. This work provides a prospective platform for combined photothermal/sonodynamic cancer therapy.

Macrokinetic Mechanism of the Combustion of 5Ti + 3Si Powder and Granular Mixtures: Effects of the Release of Impurity Gas and the Size of Titanium Particles

Macrokinetic Mechanism of the Combustion of 5Ti + 3Si Powder and Granular Mixtures: Effects of the Release of Impurity Gas and the Size of Titanium Particles

Stabilization and Dispersion of OSA Starch-Coated Titania Nanoparticles in Kappa-Carrageenan-Based Solution.

Titania is a white pigment used widely in papermaking, paints and cosmetic industries. Dispersion and stabilization of high concentration titania in water-based system remains a great bottleneck in industry nowadays, because aggregation of titania nanoparticles results in severe adverse effects to gloss, opacity, tint strength, color distribution and storage stability of end products. Because kappa-carrageenan (κ-CG) has excellent rheological properties such as emulsification, gelation, stability and so on, it has the ability to form gel and increase the viscosity of aqueous solution. In this work, Octenyl succinic anhydride (OSA) starch was utilized as wall material to encapsulate titania pigments using electrostatic spray drying processing. Transmission electron microscopy (TEM) showed that titania pigments were coated by OSA starch, with a final form of nanoparticle. Accelerating stability test found that around 60% OSA starch–titania particles were stably dispersed in κ-CG-based solution. All materials used in this work were natural ingredient, which would be preferred by cosmetic industry and consumers. The technique used in the present study could potentially be extended to other pigments for similar purpose.

Influence of the atmosphere and temperature on the properties of the oxygen-affine bonding system titanium-diamond during sintering

Grinding tools can be manufactured from metal, vitrified, and resin bond materials. In combination with superabrasives like diamond grains, metal-bonded tools are used in a wide range of applications. The main advantages of metal over vitrified and resin bonds are high grain retention forces and high thermal conductivity. This paper investigates the influence of the atmosphere and manufacturing parameters such as sintering temperature on the properties of titanium-bonded grinding layers. Titanium is an active bond material, which can increase the retention of diamond grains in metal-bonded grinding layers. This can lead to higher bond stress and, consequently, decreased wear of grinding tools in use when compared to other commonly used bond materials like bronze. The reason for this is the adhesive bond between titanium and diamond due to the formation of carbides in the interface, whereas bronze can only form a mechanical cohesion with diamond grains. However, when using oxygen-affine metals such as titanium, oxidizing effects could limit the strength of the bond due to insufficient adhesion between Ti-powder particles and the prevention of carbide formation. The purpose of this paper is to show the influence of the sintering atmosphere and temperature on the properties of titanium-bonded diamond grinding layers using the mechanical and thermal characterization of specimens. A higher vacuum (Δpatm = − 75 mbar) reduces the oxidation of titanium particles during sintering, which leads to higher critical bond stress (+ 38% @ Ts = 900 °C) and higher thermal conductivity (+ 3.4% @Ts = 1000 °C, Ta = 25 °C). X-ray diffraction measurements could show the formation of carbides in the cross-section of specimens, which also has a positive effect on the critical bond stress due to an adhesive bond between titanium and diamond.

Numerical study on the behavior of titanium particles in the process of warm spraying

Numerical study on the behavior of titanium particles in the process of warm spraying

The effect of the titanium dioxide nanoparticles on the morphology and degradation of polyamide 6 prepared by anionic ring‐opening polymerization

AbstractThermoplastic Resin Transfer Molding can be used to produce polyamide 6‐based composites from ε‐caprolactam by anionic ring‐opening polymerization. However, the service life and applicability of these composites are limited because polyamide 6 is sensitive to UV radiation. Therefore, we analyzed the effect of nanosized titanium dioxide on the UV stability of polyamide 6 produced from ε‐caprolactam. Despite the very low viscosity of caprolactam, we dispersed nanoparticles homogeneously in it before producing polyamide 6 from it. We have shown that both structural and chemical changes occur in the material under UV exposure. We proved that UV irradiation increases the crystalline fraction of the samples. This is caused by the shortening of the polymer chains. The crystalline fraction increases less with the addition of TiO2, which shows its UV protective effect. The particles prevent the rays from reaching the inside of the sample, producing a chalking effect on the surface. We analyzed and proved the chemical change in the samples by FTIR and color measurement. Our results showed that surface‐treated titanium dioxide was more stable, and the ideal filler content was about 0.6 w/w%, above which photodegradation accelerated. This can be attributed to the photocatalytic activity of the titanium dioxide particles.

MiR-92a/KLF4/p110\u03b4 regulates titanium particles-induced macrophages inflammation and osteolysis

As total joint replacement is widely applied for severe arthropathy, peri-prosthetic aseptic loosening as one of the main causes of implant failure has drawn wide attention. Wear particles such as titanium particles (TiPs) derived from prosthesis can initiate macrophages inflammation and sequentially activate osteoclasts, which results in bone resorption and osteolysis for long-term. Therefore, inhibiting wear particles induced macrophages inflammation is considered as a promising therapy for AL. In this research, we found that the inhibition of p110δ, a member of class IA PI3Ks family, could significantly dampen the TiPs-induced secretion of TNFα and IL-6. By the transfection of siRNA targeting p110δ, we confirmed that p110δ was responsible for TNFα and IL-6 trafficking out of Golgi complex without affecting their expression in TiPs-treated macrophages. As the upstream transcription-repressor of p110δ, Krüppel-like factor 4 (KLF4), targeted by miR-92a, could also attenuate TiPs-induced inflammation by mediating NF-κB pathway and M1/M2 polarization. To further ascertain the roles of KLF4/p110δ, TiPs-induced mice cranial osteolysis model was established and vivo experiments validated that KLF4-knockdown could exacerbate TiPs-induced osteolysis, which was strikingly ameliorated by knockdown of p110δ. In summary, our study suggests the key role of miR-92a/KLF4/p110δ signal in TiPs-induced macrophages inflammation and osteolysis.