Search Results (27)

Pharmaceuticals and personal care products (PPCPs), as persistent organic pollutants, are widely present in various aquatic environments. Their long-term presence in aquatic environments poses a potential threat to ecosystems and human health. This study established an efficient, green, and cost-effective photocatalytic method using P25 titanium dioxide (P25TiO₂) to simultaneously degrade five representative PPCPs (methyl paraben (MeP), carbamazepine (CBZ), bisphenol A (BPA), diclofenac (DFC), and triclosan (TCS), while elucidating the reaction mechanisms. Under sunlight irradiation, degradation rates for all five PPCPs reached 100%, achieving near-complete mineralization with total organic carbon (TOC) removal rates exceeding 95%. This demonstrates the system’s exceptional capability to not only degrade the parent compounds but to thoroughly convert them into benign inorganic substances. We systematically investigated the effects of catalyst concentration, initial pollutant concentration, light intensity, pH, and various common inorganic anions (chloride, sulfate, bicarbonate, phosphate) and humic acid (HA) on the degradation process. Additionally, mechanistic studies indicated that hydroxyl radicals (·OH) are the primary active species in the system. The degradation rate differences among various persistent organic pollutants (DFC > BPA > TCS > CBZ > MeP) primarily stem from variations in the reactivity of different functional groups within their molecular structures toward ·OH. In summary, this study provides a promising and practical solution for treating complex medical wastewater containing five typical PPCPs. Full article

The safety of titanium dioxide (TiO₂), widely used in foods and personal care products, has been of on-going concern. Adverse effects of TiO₂ have been reported, suggesting risk to human health. To evaluate its potential epigenotoxicity, the effect of exposure to a TiO₂ product, to which humans could be exposed, on microRNA (miRNA) expression (a primary epigenetic mechanism) was investigated using human cell lines (Caco-2, HCT116 (colorectal) and HepG2, SNU387 (liver)) relevant to human exposure. The effect of TiO₂ nanomaterial exposure on expression levels of miRNA was determined using the TaqMan Array Human microRNA A+B Card Set v3.0 platform. Differentially expressed miRNAs were identified (SNU387 (n = 112), HepG2 (n = 97), Caco-2 (n = 94), and HCT116 (n = 53)). Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) functional enrichment analysis of target genes provided insights into the roles of modulating pathways, which can be associated with diseases. Top 10 KEGG pathways in each cell line included MAPK signaling pathway, Axon guidance, cell cycle, Hippo signaling pathway, and Endocytosis. Findings from the study clearly demonstrate the impact of TiO₂ exposure on miRNA expression, supporting the potential involvement of this epigenetic mechanism in its biological responses. Hence, epigenetic studies are important for the complete assessment of the potential risk from exposure. Full article

Human exposure to titanium dioxide nanoparticles (TiO₂ NPs) is common. These NPs are used in cosmetics, paint, food, and other products. Their nanometric size (<100 nm) allows entry into the bloodstream, from which they can reach organs and cells throughout the body. Although TiO₂ NPs have been reported to damage certain cell lines and organs and to alter cellular function, their impact on human menstrual blood mesenchymal stem cells (hMB-MSCs) is unknown. This study evaluated the effects of TiO₂ NPs on viability, proliferation, morphology, membrane-marker expression, and reactive oxygen species (ROS) production in primary cultures of hMB-MSCs derived from menstrual blood. Cells were exposed to different concentrations of TiO₂ NPs for 3, 7, and 14 days. TiO₂ NPs decreased hMB-MSC viability and proliferation in a concentration- and time-dependent manner. Cellular viability was reduced by up to 6%, 11%, and 18% at 3, 7, and 14 days, respectively (statistically significant vs. control). Cellular proliferation decreased by 3%, 5%, and 33% at 15.63, 62.5, and 250 μg/mL TiO₂, respectively. TiO₂ NPs were internalized and observed in the cytoplasm, forming perinuclear aggregates. NP-exposed cells showed reduced membrane expression of CD73 (7.9% decrease) and CD90 (25.72% decrease) compared with control cells. Finally, TiO₂ NPs at 15.63, 62.5, and 250 µg/mL reduced ROS generation by 56.79%, 62.79%, and 53.35%, respectively, after 4 h (statistically significant vs. control). In summary, exposure to high concentrations of TiO₂ NPs leads to intracellular nanoparticle deposits and alters key functions of human menstrual blood mesenchymal stem cells, including immunomodulation, immune protection, molecular behavior, cell differentiation, and regenerative capacity. Full article

Nanosized titanium dioxide is widely used by the industry, e.g., in pigments, suncreams, and food colors. Its environmental and biological effects have been investigated in the past; however, few studiesd have focused on its crystal structure-specific effects. In our experiments, the toxicity of two types of synthetic nanoparticles was examined on primary neural cultures with different cell compositions using MTT and LDH assays. Primary murine cell cultures containing only astroglia cells originated from two brain regions, as well as mixed neurons and glia cells or microglia cells exclusively, were treated with anatase (15.8 ± 1.7 nm average diameter) and rutile (46.7 ± 2.2 nm average length and 13.7 ± 0.7 nm average diameter) TiO₂ nanoparticles at varying concentrations for 24 or 48 h. Our results show that neither anatase nor rutile nanoparticles reduced viability in cell cultures containing a mixture of neurons and glial cells, independently of the applied concentration and treatment time. Rutile but not anatase form induced cell death in cortical astroglia cultures already at 24 h of treatment above 10 µg/mL, while hippocampus-derived glial cultures were much less sensitive to rutile. The rutile form also damaged microglia. These findings suggest that products containing rutile-form nano-titanium particles may pose a targeted risk to astroglia and microglial cells in the central nervous system. Full article

The article presents the material composition of the titanium- and iron-rich ilmenite concentrate from the Satpayev deposit in Eastern Kazakhstan, which is unacceptable for processing by commercial hydro- and pyrometallurgical enrichment methods due to the presence of rutile, soluble only in hydrofluoric acid, and many refractory aluminosilicate associations: kaolinite, kyanite, pyrophyllite and mullite, cementing titanium minerals. The solution to the problem of reducing the cost of titanium sponge production was developed by developing an economically efficient and environmentally safe technology for the conversion of clayey ilmenite sand concentrate, including thermal activation of particularly resistant raw materials in an air atmosphere, soda-carbothermic smelting of cinder, hydrothermal refining of titanium slag with water, then hydrochloric acid and regeneration of reagents. Oxidative roasting ensures disintegration of intergrowths and destruction of mineral grains of the concentrate. The addition of soda ash to the concentrate cinder batch accelerates the reduction and agglomeration of over 98% of the iron, prevents the formation of lower refractory titanium oxides, facilitates the stratification of the thin-flowing titanium slag melt and cast iron and significantly reduces energy costs and the duration of the carbothermic smelting process. Refining primary titanium slag with water provides the production of modified slag with a mass fraction of TiO₂ of at least 83% and FeO of no more than 0.4%, suitable for the production of high-quality titanium sponge. Subsequent refining of modified titanium slag with 20% hydrochloric acid yields synthetic rutile of 96% purity, surpassing in the content of the main substance the branded titanium pigments of the American company DuPont. The resource-saving and environmental significance of this innovative technology is increased by the possibility of recycling easily regenerated soda, hydrochloric acid and recyclable carbon dioxide released during the decomposition of the alkaline reagent during the carbothermic smelting of the concentrate. Full article

The superhydrophobic coatings for outdoor use need to be exposed to sunlight for a long time; therefore, their UV-aging resistances are crucial in practical applications. In this study, the primary product of titanium dioxide (P-TiO₂) was used as the raw material. Nano-silica (SiO₂) was coated onto the surface of P-TiO₂ by the acid precipitation method to prepare P-TiO₂-SiO₂ composite particles. Then, they were modified and sprayed simply to obtain a superhydrophobic P-TiO₂-SiO₂/HDTMS coating. The results indicated that amorphous nano-SiO₂ was coated on the P-TiO₂ surface, forming a micro–nano binary structure, which was the essential structure to form superhydrophobic coatings. Additionally, the UV-aging property of P-TiO₂ was significantly enhanced after being coated with SiO₂. After continuous UV irradiation for 30 days, the color difference (ΔE*) and yellowing index (Δb*) values of the coating prepared with P-TiO₂-SiO₂ increased from 0 to 0.75 and 0.23, respectively. In contrast, the ΔE* and Δb* of the coating prepared with P-TiO₂ increased from 0 to 1.68 and 0.74, respectively. It was clear that the yellowing degree of the P-TiO₂-SiO₂ coating was lower than that of P-TiO₂, and its UV-aging resistance was significantly improved. After modification with HDTMS, the P-TiO₂-SiO₂ coating formed a superhydrophobic P-TiO₂-SiO₂/HDTMS coating. The water contact angle (WCA) and water slide angle (WSA) on the surface of the coating were 154.9° and 1.3°, respectively. Furthermore, the coating demonstrated excellent UV-aging resistance. After continuous UV irradiation for 45 days, the WCA on the coating surface remained above 150°. Under the same conditions, the WCAs of the P-TiO₂/HDTMS coating decreased from more than 150° to 15.3°. This indicated that the retention of surface hydrophobicity of the P-TiO₂-SiO₂/HDTMS coating was longer than that of P-TiO₂/HDTMS, and the P-TiO₂-SiO₂/HDTMS coating’s UV-aging resistance was greater. The superhydrophobic P-TiO₂-SiO₂/HDTMS self-cleaning coating reported in this study exhibited outstanding UV-aging resistance, and it had the potential for long-term outdoor use. Full article

The present study demonstrates, for the first time, the fundamental possibility of producing electrode materials for sodium-ion batteries through low-temperature carbothermic smelting of ilmenite concentrate fluxed with calcined soda and diatomite, followed by aqueous refining of titanium slag. The primary phase composition of the slag includes Na₂Ti₃O₇ (48.2%), Na_0.23TiO₂ (22.0%), Na₂TiSiO₅ (11%), and Na_0.67Al_0.1Mn_0.9O₂ (8.5%), which, upon hydrolysis, transform into a monophase titanium dioxide with intercalated sodium—Na_0.23TiO₂. Thermodynamic analysis of the heat effects of chemical reactions among raw materials and resulting products substantiates the role of silicon and sodium oxides, carbon, oxygen, and water in the formation of various electrode materials during carbothermic flux conversion and aqueous refining. Insights into the mechanisms of thermochemical formation and hydrothermal phase transformations offer a scientific basis for the development of intercalation systems from abundant and low-cost natural raw materials, bypassing the need for expensive precursor synthesis. Full article

The safety of titanium dioxide (TiO₂), widely used in foods and personal care products, has been of ongoing concern. Significant toxicity of TiO₂ has been reported, suggesting a risk to human health. To evaluate its potential epigenotoxicity, the effect of exposure to a TiO₂ product to which humans could be exposed on DNA methylation, a primary epigenetic mechanism, was investigated using two human cell lines (Caco-2 (colorectal) and HepG2 (liver)) relevant to human exposure. Global methylation was determined by enzyme-linked immunosorbent assay-based immunochemical analysis. Gene promoter methylation was evaluated using EpiTect Methyl II Signature PCR System Array technology. Expression of DNA methyltransferases, MBD2, and URHF1 was quantified by qRT-PCR. A decrease in global DNA methylation was observed in both cell lines. Across the cell lines, seven genes (BNIP3, DNAJC15, GADD45G, GDF15, INSIG1, SCARA3, and TP53) were identified in which promoters were methylated. Changes in promoter methylation were associated with gene expression. Results also revealed aberrant expression of regulatory genes, DNA methyltransferases, MBD2, and UHRF1. Findings from the study clearly demonstrate the impact of TiO₂ exposure on DNA methylation in two cell types, supporting the potential involvement of this epigenetic mechanism in its biological responses. Hence, epigenetic studies are critical for complete assessment of potential risk from exposure. Full article

Silica (SiO₂), titanium dioxide (TiO₂), and zinc oxide (ZnO) nanoparticles (NPs) are widely used in dermal products. Their skin sensitization potential, especially their effects in combination with known sensitizers, is poorly studied in vitro and their sensitization inconsistently reported in animal studies. In this study, cellular assays were used to identify different steps of sensitization, the activation of keratinocytes and dendritic cells, when cells were exposed to these NPs in the absence and presence of sensitizers. Cellular systems included HaCaT keratinocytes and U937 (U-SENS™) alone, as well as different co-culture systems of THP-1 cells with HaCaT cells (COCAT) and with primary keratinocytes. The effect of NPs differed between co-cultures and U-SENS™, whereas co-cultures with either primary keratinocytes or HaCaT cells responded similarly. Pre-exposure to ZnO NPs increased the U-SENS™ assay response to 2,4-dinitrochlorobenzene six-fold. The COCAT increase was maximally four-fold for the combination of SiO₂ and trans cinnamaldehyde. When the THP-1 cells were separated from the keratinocytes by a membrane, the response of the co-culture system was more similar to U-SENS™. The direct contact with keratinocytes decreased the modulating effect of TiO₂ and ZnO NPs but suggested an increase in response to sensitizers following dermal contact with SiO₂ NPs. Full article

Titanium dioxide (TiO₂) is a prevalent food additive, yet comprehensive data on particle size and dietary exposure are lacking in China. Transmission electron microscopy results revealed that the quantitative proportion of nanoparticles (NPs) in food-additive TiO₂ was 37.7%, with a mass fraction of 9.89%. Laboratory test results showed that among the domestic products surveyed, candies excluding gum-based candies contained the highest content of TiO₂. Using consumption data from the China Health and Nutrition Survey in 2018, the average dietary exposure for TiO₂ and TiO₂ NPs in the Chinese population were calculated at 34.84 and 3.44 μg/kg bw/day, respectively. The primary dietary sources were puffed food and powdered drinks. Exposure varied significantly across age and region, with children and Inner Mongolia residents having the highest intake. TiO₂ NP exposure showed a negative correlation with age. Despite this, the dietary exposure risk of TiO₂ NPs for the Chinese population remains deemed acceptable. Full article

Emerging pollutants such as microplastics in water environments readily accumulate microorganisms on their surfaces, forming biofilms and concentrating antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Consequently, microplastic biofilms have attracted the attention of researchers. Horizontal gene transfer (HGT) of ARGs is one of the primary ways that bacteria acquire antibiotic resistance. Most studies focus on the effects of nanomaterials on suspended bacteria, but microplastic biofilms as hotspots for horizontal gene transfer also warrant significant investigation. This study primarily explored and compared the effects of nano-titanium dioxide on the conjugation transfer frequency of ARGs in suspended bacteria and microplastic biofilms. Nano-titanium dioxide could promote ARG conjugation in both suspended bacteria and microplastic biofilms, with a greater effect on the former. The mechanism involved nano-titanium dioxide promoting the production of reactive oxygen species (ROS) in suspended and biofilm bacteria, increasing the synthesis of outer membrane proteins, enhancing the cell membrane permeability, and elevating the expression levels of conjugation-related genes, thereby facilitating the conjugation transfer of ARGs. Biofilm bacteria, being heavily encased and protected by extracellular polymeric substances (EPS), exhibit greater resistance to external environmental pressure, resulting in the weaker impact of nano-titanium dioxide on biofilm bacteria compared to suspended bacteria. This study reveals the risk of ARG conjugation transfer within microplastic biofilms induced by nanomaterials, providing valuable insights into the risks of microplastic and antibiotic resistance dissemination in water environments. Full article

Achieving lightweight, high-strength, and biocompatible composites is a crucial objective in the field of tissue engineering. Intricate porous metallic structures, such as lattices, scaffolds, or triply periodic minimal surfaces (TPMSs), created via the selective laser melting (SLM) technique, are utilized as load-bearing matrices for filled ceramics. The primary metal alloys in this category are titanium-based Ti6Al4V and iron-based 316L, which can have either a uniform cell or a gradient structure. Well-known ceramics used in biomaterial applications include titanium dioxide (TiO₂), zirconium dioxide (ZrO₂), aluminum oxide (Al₂O₃), hydroxyapatite (HA), wollastonite (W), and tricalcium phosphate (TCP). To fill the structures fabricated by SLM, an appropriate ceramic is employed through the spark plasma sintering (SPS) method, making them suitable for in vitro or in vivo applications following minor post-processing. The combined SLM-SPS approach offers advantages, such as rapid design and prototyping, as well as assured densification and consolidation, although challenges persist in terms of large-scale structure and molding design. The individual or combined application of SLM and SPS processes can be implemented based on the specific requirements for fabricated sample size, shape complexity, densification, and mass productivity. This flexibility is a notable advantage offered by the combined processes of SLM and SPS. The present article provides an overview of metal–ceramic composites produced through SLM-SPS techniques. Mg-W-HA demonstrates promise for load-bearing biomedical applications, while Cu-TiO₂-Ag exhibits potential for virucidal activities. Moreover, a functionally graded lattice (FGL) structure, either in radial or longitudinal directions, offers enhanced advantages by allowing adjustability and control over porosity, roughness, strength, and material proportions within the composite. Full article

Although several studies assess the biological effects of micro and titanium dioxide nanoparticles (TiO₂ NPs), the literature shows controversial results regarding their effect on bone cell behavior. Studies on the effects of nanoparticles on mammalian cells on two-dimensional (2D) cell cultures display several disadvantages, such as changes in cell morphology, function, and metabolism and fewer cell–cell contacts. This highlights the need to explore the effects of TiO₂ NPs in more complex 3D environments, to better mimic the bone microenvironment. This study aims to compare the differentiation and mineralized matrix production of human osteoblasts SAOS-2 in a monolayer or 3D models after exposure to different concentrations of TiO₂ NPs. Nanoparticles were characterized, and their internalization and effects on the SAOS-2 monolayer and 3D spheroid cells were evaluated with morphological analysis. The mineralization of human osteoblasts upon exposure to TiO₂ NPs was evaluated by alizarin red staining, demonstrating a dose-dependent increase in mineralized matrix in human primary osteoblasts and SAOS-2 both in the monolayer and 3D models. Furthermore, our results reveal that, after high exposure to TiO₂ NPs, the dose-dependent increase in the bone mineralized matrix in the 3D cells model is higher than in the 2D culture, showing a promising model to test the effect on bone osteointegration. Full article

Glyphosate is one of the most widely used pesticides, which, together with its primary metabolite aminomethylphosphonic acid, remains present in the environment. Many technologies have been developed to reduce glyphosate amounts in water. Among them, heterogeneous photocatalysis with titanium dioxide as a commonly used photocatalyst achieves high removal efficiency. Nevertheless, glyphosate is often converted to organic intermediates during its degradation. The detection of degraded glyphosate and emerging products is, therefore, an important element of research in terms of disposal methods. Attention is being paid to new sensors enabling the fast detection of glyphosate and its degradation products, which would allow the monitoring of its removal process in real time. The surface plasmon resonance imaging (SPRi) method is a promising technique for sensing emerging pollutants in water. The aim of this work was to design, create, and test an SPRi biosensor suitable for the detection of glyphosate during photolytic and photocatalytic experiments focused on its degradation. Cytochrome P450 and TiO₂ were selected as the detection molecules. We developed a sensor for the detection of the target molecules with a low molecular weight for monitoring the process of glyphosate degradation, which could be applied in a flow-through arrangement and thus detect changes taking place in real-time. We believe that SPRi sensing could be widely used in the study of xenobiotic removal from surface water or wastewater. Full article

Nowadays, lithium-ion batteries (LIBs) are one of the most convenient, reliable, and promising power sources for portable electronics, power tools, hybrid and electric vehicles. The characteristics of the positive electrode (cathode active material, CAM) significantly contribute to the battery’s functional properties. Applying various functional coatings is one of the productive ways to improve the work characteristics of lithium-ion batteries. Nowadays, there are many methods for depositing thin films on a material’s surface; among them, one of the most promising is atomic layer deposition (ALD). ALD allows for the formation of thin and uniform coatings on surfaces with complex geometric forms, including porous structures. This review is devoted to applying the ALD method in obtaining thin functional coatings for cathode materials and includes an overview of more than 100 publications. The most thoroughly investigated surface modifications are lithium cobalt oxide (LCO), lithium manganese spinel (LMO), lithium nickel-cobalt-manganese oxides (NCM), lithium-nickel-manganese spinel (LNMO), and lithium-manganese rich (LMR) cathode materials. The most studied processes of deposition are aluminum oxide (Al₂O₃), titanium dioxide (TiO₂) and zirconium dioxide (ZrO₂) films. The primary purposes of such studies are to find the synthesis parameters of films, to find the optimal coating thickness (e.g., ~1–2 nm for Al₂O₃, ~1 nm for ZrO₂, <1 nm for TiO₂, etc.), and to reveal the effect of the coating on the electrochemical parameters of batteries. The review summarizes synthesis conditions, investigation results of deposited films on CAMs and positive electrodes and some functional effects observed due to films obtained by ALD on cathodes. Full article