Search Results (463)

Photodynamic therapy (PDT) is a promising cancer treatment employing photo-induced reactive oxygen species (ROS) generation by a photosensitizer (PS). Titanium dioxide (TiO₂) is a potential PS due to its superb photocatalytic features and biocompatibility. However, its clinical potential is restricted by its predominant ultraviolet (UV) absorption. To address this limitation, this work introduces TiO₂/carbon dots (CDs) nanohybrid materials for improving the photophysical properties of TiO₂ and its photodynamic performance. TiO₂ and CDs were synthesized through wet chemical and hydrothermal techniques, and subsequently combined via a facile ex situ solvothermal process to produce hybrid materials containing 1–50% w/w CDs. The materials were characterized using XRD, Raman, TEM, FT-IR, zeta potential, TGA, UV-Vis and PL. PDT studies on A431 skin cancer cells indicated improved photosensitizing ability of TiO₂/CDs, with TiO₂/CDs (10%) inducing 47% cell toxicity, versus 20% for TiO₂ after 10 min of red-light irradiation (661 nm, 18 mW/cm², 12.96 J/cm²). Intracellular localization studies revealed enhanced cellular uptake of TiO₂/CDs (10%), compared with TiO₂. In vitro studies on 3T3 healthy fibroblasts confirmed PSs’ safety both with and without light. Overall, this study elucidates the key role of CDs in the photophysical and photodynamic behavior of TiO₂-based systems, providing design guidelines for the next-generation inorganic PSs. Full article

Effluents from industries, manufacturing companies, textile looms, and floodwater contaminate the surface water reservoirs. This endangers the quality of water for use by humans. Wastewater remediation is one of the ways to recycle the dirty water and make it suitable for use. Photocatalysis is the most common method for wastewater remediation, especially using Titanium dioxide (TiO₂) nanoparticles. However, chemical synthesis and direct addition of nanoparticles may cause toxicity to the flora and fauna present in the water body. To address this limitation, we have green-synthesized TiO₂ nanoparticles using a horticulture waste, Calendula officinalis dried flower extract and entrapped them in a natural polymer, chitosan (CTS-TiO₂-CO nanocomposite). The polymer entrapment ensures biocompatibility as well as reduced aggregation of nanoparticles. The synthesized CTS-TiO₂-CO nanocomposite was characterized using UV-visible spectrophotometry, dynamic light scattering, zeta potential, Fourier Transformed Infrared Spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX) analysis. The absorption peak was found at 302 nm, and the hydrodynamic diameter at 490 nm. SEM images show flower-like morphology with 326 nm average particle diameter. The non-toxic dose of the nanoparticles was estimated by MTT assay and zebrafish embryo developmental studies. More than 82% fibroblast cells were viable after treatment with 100 μg/mL of CTS-TiO₂-CO nanocomposite. 85% embryos hatched after treatment with 50 μg/mL of CTS-TiO₂-CO nanocomposite. Further, the textile dye remediation assessment was done using the dye crystal violet, exhibiting 69.19% dye degradation after 4 h of sunlight exposure. Altogether, the results demonstrate that the CTS-TiO₂-CO nanocomposite was effective in the remediation of crystal violet without causing any toxicity up to a dose of 100 μg/mL. Full article

Background: Tantalum in cytotoxicity tests showed no toxicity effect, as well as promoting bone regeneration through the differentiation, proliferation, mineralisation and adhesion of osteoblasts in in vitro and in vivo studies. This study aims to determine and compare the chemical composition, roughness and wettability of non-coated commercially pure titanium (CpTi) disc surfaces with CpTi discs that have been coated with tantalum oxynitride film (TaON) via a modified plasma sputtering coating technique. Methods: Two groups were tested that included the TaON-coated CpTi discs and non-coated CpTi discs. A modified reactive plasma sputtering apparatus was used for coating the CpTi discs with TaON at different time durations, i.e., 4, 6, and 8 h. The surface properties of the coated and non-coated discs were studied using X-ray diffraction (XRD) analysis, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and contact angle measurement. Results and Conclusions: The results showed that 8 h was the best coating duration. The XRD analysis showed the presence of a new peak in the case of the TaON-coated CpTi disc that was absent in the non-coated CpTi disc. Furthermore, the SEM analysis revealed that the TaON-coated CpTi disc showed a better distribution of surface roughness compared to the non-coated disc. The non-coated CpTi discs showed lower wettability compared to the TaON-coated CpTi discs. The result shows the importance of a TaON coat in changing the surface properties of CpTi which will be used in dental implants; this result will enhance the idea of surface treatment and its relationship with the enhancement and acceleration of bone formation around dental implants in future. The novelty of the newly modified reactive plasma sputtering technique used in this study as a coating technique for CpTi discs lies in the promising tantalum oxynitride, as Ta had no toxicity effect in cytotoxicity tests and promoted adhesion, proliferation, differentiation, the mineralisation of osteoblasts and bone regeneration in vitro and in vivo. The mean target of the work is to enhance the osseointegration of CPTi dental implants with different surface coatings including Ta oxide, nitride and oxynitride. The results of the first two coatings are already published, and the third coating technique is investigated in this study. Full article

Metal–organic frameworks (MOFs) possess ordered pore structure, high surface area, tunable composition and tailorable functionality, and thus present promising prospect in many applications. Among them, titanium-based MOFs (Ti-MOFs) composed of organic ligands and titanium–oxygen clusters exhibit great potential in photocatalysis, owing to their diverse topological configurations, outstanding photocatalytic activity, low toxicity, and easy production. The latest developments in Ti-MOFs, including the synthetic strategies, structural features, methods for enhancing catalytic performance, and typical applications, were reviewed in this paper. The application in CO₂ reduction, hydrogen evolution, organic pollutant removal, and photocatalytic sensing were emphasized. Moreover, we present a distinctive perspective on the relationship between the structure and their applications of Ti-MOFs, and provide new information in the design and construction of advanced Ti-MOFs for high-efficiency photocatalytic conversion. Full article

Historically, the toxicological evaluation of poorly soluble low toxicity particles (PSLTs), such as titanium dioxide nanoparticles (TiO₂ NPs), distinct from conventional pigment-grade TiO₂, has focused on carcinogenicity and lung overload, leaving their pathological function in the development of pneumoconiosis undefined. In this study, we initiated a “Pneumoconiosis Renaissance”, redefining the human “Gold Standard” of pneumoconiosis pathology as a primarily interstitial “Dust Macule (DM) to Mixed Dust Fibrosis (MDF) axis”. In contrast, rats developed a species-specific “Airspace-Dominant Phenotype” (Pulmonary Dust Foci) driven by airspace stagnation. Integrating recent continuous inhalation exposure and recovery after inhalation exposure studies, we demonstrate that this overwhelming alveolar pathology in rats acts as a “Biological Mask”, physically superimposing upon and obscuring human-relevant interstitial sequestration. Crucially, however, extended recovery periods can unmask these interstitial events, revealing the true underlying pathology. We propose that future risk assessments and Adverse Outcome Pathways (AOPs) must incorporate spatial resolution. By rigorously segregating sensitive rat-specific airspace events from human-relevant interstitial remodeling, we can accurately bridge the interspecies gap. This review argues that rather than discarding the rat model, we must learn to decode it—using spatial distinctions to filter the airspace mask and evaluate the true interstitial risk of inhaled biodurable particles. Full article

Photocatalysis is a process in which a material utilizes light energy to degrade contaminants through oxidation reactions that decompose impurities upon contact with its surface. Titanium dioxide is one of the most widely used semiconductor materials due to its abundance, chemical stability, and non-toxicity. However, its relatively wide bandgap restricts its photocatalytic activity to the ultraviolet region of the solar spectrum, limiting its overall efficiency under natural sunlight. The incorporation of copper nanoparticles into the TiO₂ matrix enhances light absorption by extending its activity into the visible range, thereby improving its energy conversion efficiency. In this study, undoped and Cu-doped TiO₂ powders were synthesized using the mechanochemical method. The characteristics of the prepared photocatalyst material were determined by XRD, SEM, absorbance, and chemical analysis. XRD analysis showed the formation of TiO₂ in its anatase and rutile phases. Sphere-like shapes with a size of 100 nm were inferred from SEM images. The photocatalytic tests revealed that the Cu-doped TiO₂ nanoparticles exhibited high photocatalytic activity in degrading contaminated water. This enhancement can be attributed to the formation of oxygen vacancies, which promote the photodegradation of organic compounds. Full article

Background/Objectives: The main objective of optimizing the composition of dental implants is to improve tissue compatibility for enhanced biological/biochemical performance. In this context, research on the development of new titanium alloys in dental implantology considers the careful selection of alloying elements, both in terms of biocompatibility (their lack of toxicity) and their potential to improve the metallurgical processing capacity (thermal and/or thermomechanical), which through controlled microstructural changes lead to the optimal combination of properties for functionality and durability of the implant. The purpose of the research is to study the influence of alloying elements on the phase composition and physical–mechanical properties of experimental titanium alloys. Methods: Four alloys with original chemical compositions were developed, coded in the experiments as follows: Ti1, Ti2, Ti3, Ti4. The characterization of the alloys was carried out by detailed analysis of the chemical composition, phase structure and by testing the physico-mechanical properties (HV hardness, tensile strength, yield strength, elongation, modulus of elasticity), by standardized modern methods. Characterization methods, such as optical microscopy, SEM, EDS and XRD were performed, followed by tensile tests based on ASTM EB/EBM-22 and EN ISO 6892-1-2009 standards. Results: The research results provide information regarding the relationship between the composition and the physico-mechanical properties (Rm, Rp, HV, A, G, E) of the experimental alloys (Ti1–Ti4). Depending on the value level of the properties, these have been highlighted: compositions in which the alloy can be indicated for conditions of intense stress (Ti3), compositions that describe highly ductile alloys, easy to process and adapt to clinical requirements (Ti4), but also alloys compositions characterized by a balanced combination of strength, plasticity/ductility (Ti1, Ti2). Conclusions: Research for the development of new titanium alloys through the optimization of chemical composition has taken into account the requirements regarding the biological/biomechanical compatibility of biomaterials. Analyzed in comparison with Cp-Ti grade 4 and Ti6A4V, the experimental alloys (Ti1–Ti4) can be characterized as follows: The mechanical strength properties (Rm and Rp) are higher than those of pure commercial titanium (Cp-Ti grade 4) for all compositions Ti1–Ti4, but slightly lower than those of alloy Ti6Al4V. The plasticity–ductility properties have values comparable to those of Cp-Ti grade 4 (Ti4 and Ti2 compositions) and Ti6Al4V (Ti1 composition), with one exception, the Ti3 alloy. All four experimental alloys have a lower modulus of elasticity than Cp-Ti grade 4 (102–104 GPa) and Ti6Al4V (113 GPa), commonly used in dental implants. An in-depth analysis, which will also consider information on corrosion behavior and cellular testing, may support the selection of some of the four experimental alloys studied. The research aims to continue the progress to a higher level of testing, through the realization of dental implants (e.g., fatigue, wear, osteointegration capacity, etc.). Full article

The increasing environmental release of nano-titanium dioxide (nTiO₂) due to its widespread industrial application raises concerns about its potential effects on aquatic ecosystems, particularly marine organisms. Fertilization, a critical reproductive process for broadcast-spawning bivalves, is highly sensitive to environmental pollutants. In the present investigation, we explored the effects of nTiO₂ at environmentally relevant concentrations on oocyte quality and the fertilization process in the economically important marine bivalve Tegillarca granosa. nTiO₂ exposure significantly reduced fertilization success and sperm–egg fusion efficiency, while markedly increasing polyspermy incidence. Mechanistically, nTiO₂ triggered oxidative stress in oocytes, elevating ROS and MDA levels and causing structural damage to the oocyte membrane. Moreover, nTiO₂ exposure disrupted cellular energy metabolism by inhibiting PK and PFK activities, depleting ATP content, and reducing MMP. Additionally, nTiO₂ exposure impaired Ca²⁺ homeostasis by suppressing Ca²⁺-ATPase activity, which reduced intracellular Ca²⁺ levels. These cellular disruptions collectively compromised the cortical reaction by inhibiting cortical granule exocytosis and microfilament migration. Our findings suggest that nTiO₂-induced oxidative stress, coupled with an imbalance in energy and Ca²⁺ homeostasis, impairs the cortical reaction and fertilization capacity in T. granosa. This study provides valuable insights into the mechanistic pathway underlying the reproductive toxicity of nTiO₂ in marine invertebrates, offering a basis for evaluating the ecological risks associated with the presence of nanomaterials in marine environments. Full article

Effective management of water quality is critical for Litopenaeus vannamei aquaculture, yet it remains a significant technological hurdle for traditional farmers facing benthic anaerobiosis and toxic metabolite accumulation. This study introduces a novel approach by synergistically integrating calcium peroxide (CaO₂), titanium dioxide (TiO₂), and peracetic acid (PAA) encapsulated within Fe–alginate granules. Unlike conventional methods that treat oxygen depletion and toxicity separately, this composite is designed to simultaneously facilitate in situ oxygenation and advanced oxidation processes (AOPs) directly at the sediment–water interface. The physicochemical properties and radical generation mechanisms of the synthesized composites were characterized using FTIR, XRD, SEM, and ESR. In laboratory simulations of pond conditions, the synergistic efficacy of these composites was evaluated against critical parameters, including dissolved oxygen (DO), ammonia, and sulfide. Experimental results revealed that the application of 5 mg/L CP-T-PAA product to the sediment with an AOP system exhibited superior performance, generating the highest intensity of hydroxyl (•OH) and superoxide (•O₂⁻) radicals. This optimized treatment effectively maintained DO levels above ~2 mg/L at the sediment–water interface for 21 days (3 weeks) and achieved removal efficiencies of 94% for ammonia, 89% for sulfide, and 93% for turbidity. Multi-criteria decision analysis (TOPSIS) validated this formulation as the ideal solution. Consequently, this novel composite presents a sustainable, user-friendly strategy for enhancing environmental stability in traditional shrimp farming. Full article

Photocatalytic reduction of carbon dioxide is a very effective strategy to address the energy crisis and greenhouse effect. TiO₂ is a widely used semiconductor photocatalyst, which has excellent catalytic activity, excellent chemical stability and low toxicity. Nevertheless, TiO₂ still has some inherent limitations, such as: wide band gap, high carrier recombination rate, and low adsorption activation ability for carbon dioxide. These drawbacks severely restrict its further application in the photocatalytic reduction of CO₂. In this study, cotton-like blue C/TiO₂ NTs are successfully synthesized through the in situ growth of TiO₂ nanotubes on the MIL-125(Ti)-derived C/TiO₂ precursor. The experimental results revealed that the CO production rate of the cotton-like blue C/TiO₂ NTs was 1.84 times that of C/TiO₂ and 3.78 times that of TiO₂ nanotubes. These results clearly demonstrate that the cotton-like blue C/TiO₂ NTs exhibit a broad spectral response, a large specific surface area, and an abundance of oxygen vacancies. This research provides new insights into the design of titanium dioxide-based photocatalytic materials and opens up a promising avenue for enhancing the performance of titanium dioxide in the photocatalytic reduction of carbon dioxide. Full article

Phosphorus-modified poly(vinyl alcohol) (PVA) has recently gained increasing attention as a functional polymeric matrix suitable for gel-based systems, owing to its biocompatibility, film-forming ability, and capacity to develop semi-interpenetrating networks. In this work, PVA was chemically modified through the nucleophilic substitution of its hydroxyl groups with the chloride groups of phenyl dichlorophosphate, following a literature-reported method carried out in N,N-dimethylformamide (DMF) as reaction medium, resulting in phosphorus-containing PVA networks (PVA-OP3). Hybrid gel-like films were then prepared by incorporating titanium dioxide nanoparticles (TiO₂ NPs), known for their antimicrobial activity, low toxicity, and high stability. The resulting composites were structurally, morphologically, and thermally characterized using FTIR, SEM, and thermogravimetric analysis. The incorporation of TiO₂ NPs significantly improved the thermal stability, with T₅% increasing from 240 °C for neat PVA-OP3 to 288 °C for the optimal composite, increased the char residue from 4.5% for the neat polymer to 30.1% for PVA-OP3/TiO₂-4, and enhanced antimicrobial activity against both Gram-positive and Gram-negative bacteria. These findings demonstrate that PVA-OP3/TiO₂ hybrid films possess promising potential as advanced biomaterials for biomedical, protective, and environmental applications. Full article

Titanium-based bulk metallic glasses (BMGs) offer high strength, lower stiffness than Ti-6Al-4V, and superior corrosion resistance, but conventional Ti glass-forming systems often contain toxic Ni, Be, or Cu. This work investigates five novel Ti-based alloys free of these elements—Ti₄₂Zr₃₅Si₅Co_12.5Sn_2.5Ta₃, Ti₄₂Zr₄₀Ta₃Si₁₅, Ti₆₀Nb₁₅Zr₁₀Si₁₅, Ti₃₉Zr₃₂Si₂₉, and Ti_65.5Fe_22.5Si₁₂—synthesized by arc melting and suction casting. Single-track laser remelting using a selective laser melting (SLM) system was performed to simulate additive manufacturing and examine microstructural evolution, cracking behavior, mechanical properties, and cytocompatibility. All alloys solidified into fully crystalline α/β-Ti matrices with Ti/Zr silicides; no amorphous structures were obtained. Laser remelting refined the microstructure but did not induce glass formation, consistent with the known limited glass-forming ability of Cu/Ni/Be-free Ti systems. Cracking was observed at low laser energies but crack density decreased as laser energy increased. Cracks were eliminated above ~0.4 J/mm for most alloys. Ti₄₂Zr₃₅Si₅Co_12.5Sn_2.5Ta₃ exhibited the lowest stiffness (~125 GPa), while Ti₆₀Nb₁₅Zr₁₀Si₁₅ showed the highest due to silicide precipitation. Cytotoxicity tests (ISO 10993-5) confirmed all alloys to be non-toxic, with some extracts even enhancing fibroblast proliferation. This rapid laser-remelting approach enables cost-effective screening of Ti-based glass-forming alloys for additive manufacturing. Ti–Zr–Ta–Si systems demonstrated the most promising properties for further testing using the powder bed method. Full article

Mercury (Hg²⁺) contamination in water systems poses a severe environmental and health hazard due to its high toxicity and bioaccumulation potential. In this study, a novel adsorbent was developed by sequentially modifying kaolin via acid–base treatment, titanium dioxide (TiO₂) incorporation, and 3-aminopropyltriethoxysilane (APTES) grafting. Batch adsorption experiments revealed that the fully modified kaolin (TiO₂-loaded and APTES grafted) exhibited the highest adsorption capacity (25.6 mg/g) compared to the acid–base-treated (5.8 mg/g) and TiO₂-loaded (17.7 mg/g) kaolin. Under optimal conditions (75 mg adsorbent dosage; 70 mg/L Hg²⁺; pH 5), the fully modified kaolin maintained its performance even in the presence of varying ionic strengths, natural organic matter, and competing metal ions. Adsorption kinetics followed a pseudo-second-order model, and the equilibrium data were well fitted by the Langmuir isotherm. Antibacterial activity assay revealed that the TiO₂-loaded kaolin effectively inhibited S. aureus (minimum inhibitory concentration = 2.5 mg/mL) and showed moderate activity against E. coli (BL21) (minimum inhibitory concentration = 5 mg/mL). However, antibacterial activity decreased after amine functionalization, indicating a compromise between enhancing adsorption capacity and preserving antibacterial functionality. This study presents a promising cost-efficient approach for the simultaneous removal of Hg²⁺ ions from water matrices and inhibiting bacterial growth, aligning with SDG 6 (Clean Water and Sanitation). Full article

Total ammonia nitrogen (TAN) is a common and potent neurotoxic pollutant in aquatic environments. Due to their strong adsorption capacity, titanium dioxide nanoparticles (n-TiO₂), a widely used engineered material, can induce combined toxicity with multiple pollutants. However, the combined neurotoxicity of n-TiO₂ and TAN and its underlying mechanisms remain unclear. In this study, zebrafish embryos were exposed to TAN (0, 0.1, 1, 10 mg/L) and n-TiO₂ (100 µg/L) individually or in combination for 120 h. The results indicated that co-exposure to n-TiO₂ and TAN significantly increased the bioaccumulation of TAN in zebrafish embryos compared to TAN alone. Consequently, this led to exacerbated neurotoxicity, manifested as developmental impairments and abnormal motor behavior. Mechanistic investigations revealed that the co-exposure aggravated developmental neurotoxicity by triggering neuronal apoptosis and oxidative stress, disrupting the cholinergic and dopaminergic systems, and impairing neural and retinal development. Transcriptomic analysis further indicated that the co-exposure predominantly perturbed neurodevelopment, oxidative stress, and apoptosis. In conclusion, this study confirms that n-TiO₂ significantly amplifies TAN-induced neurodevelopmental toxicity by promoting its bioaccumulation and synergistically disrupting multiple neurophysiological processes. These findings provide crucial scientific evidence for assessing the combined ecological risks of nanomaterials and conventional pollutants. Full article

It is well known that nitrite is widely used in industrial and agricultural sectors as a preservative, corrosion inhibitor, and intermediate in chemical synthesis; consequently, nitrite residues are often present in food, water, and the environment as a result of meat curing, fertilizer use, and wastewater discharge. Despite having several applications, nitrite exerts toxic effects on human beings and aquatic life. Therefore, the monitoring of nitrite is of particular significance to avoid negative impacts on human health, the environment, and aquatic life. Previously, the electrochemical method has been extensively used for the development of nitrite sensors using various advanced electrode materials. Additionally, zinc oxide (ZnO), cerium oxide (CeO₂), titanium dioxide (TiO₂), copper oxide (CuO), iron oxides, nickel oxide (NiO), polymers, MXenes, reduced graphene oxide (rGO), carbon nanotubes (CNTs), graphitic carbon nitride (gCN), metal–organic frameworks (MOFs), and other composites have been utilized as electrocatalysts for the fabrication of nitrite electrochemical sensors. This review article provides an overview of the construction of nitrite sensors using advanced electrode materials. The electrochemical activities of the reported nitrite sensors are discussed. Furthermore, limitations and future perspectives regarding the determination of nitrite are discussed. Full article