TiO2 Nanoparticles Research Articles

Two-photon photodynamic therapy with curcumin nanocomposite

Two-photon photodynamic therapy (TP-PDT) offers an innovative approach to cancer treatment that utilizes near-infrared light to activate photosensitizers and generate reactive oxygen species (ROS) for targeted cancer cell elimination. TiO2-CUR-Sofast (TCS), which uses TiO2 nanoparticles and Sofast cationic polymer to modify curcumin (CUR), has demonstrated potential as a photosensitizer under visible light irradiation, addressing the limitations of CUR's narrow spectral range and low bioavailability. This study explores the utility of the two-photon technique to activate TCS within the infrared spectrum, aiming to enhance ROS production and penetration depth compared to traditional CUR. TCS exhibits a significantly higher ROS production at 900 nm excitation wavelength, approximately 6–7 times that of CUR, signifying a substantial increase in efficiency. In TP-PDT, TCS showed significant phototoxicity against HeLa and T24 cell lines compared to CUR. Furthermore, TCS's photodynamic efficacy is further confirmed by cell apoptosis and necrosis studies, where approximately 89 % of cells treated with TCS under 900 nm light irradiation were observed in an apoptosis/necrosis state. And the TP-PDT effect in deep tissue was simulated using pig skin. It shows that the two-photon excitation has a significant penetration depth advantage over the single-photon excitation. These results indicate that the two-photon PDT scheme of TCS has greater potential than the single-photon PDT scheme in the treatment of cancer, and provides an experimental foundation for the effective treatment of deep lesions.

Polysulfone (Psf) Mixed Matrix Membrane incorporating Titanium Dioxide (TiO2)/Polyethylene Glycol (PEG) for the removal of copper

The global increasing contamination of water resources with toxic metals such as copper (Cu), poses severe threats to human health and aqueous ecosystems. Therefore, the ultrafiltration mixed matrix membranes (UF MMMs) possess an applicable approach for the removal of copper ions. This novel fabricated technology can be applied in various wastewater treatment systems for the removal of heavy metals, especially copper. MMMs were fabricated by blending polysulfone (Psf) with additives into the dope solution via the phase inversion method by incorporating titanium dioxide (TiO2) and polyethylene glycol (PEG) in Psf MMMs. Seven Psf MMMs samples labelled M0 to M6, each with its own formulation, were prepared and tested for density, porosity, and degree of Cu retention. MMMs were further characterized via Fourier transform infrared spectroscopy (FTIR), which revealed the range of the IR spectrum of Psf polymer membrane from 1319 cm-1 to 1600 cm-1, 1650 cm-1 to 3400 cm-1 for PEG, and 800 cm-1 to 3600 cm-1 for TiO2 NPs. As for the scanning electron microscopy (SEM), M6 (Psf/TiO2/PEG 6000) was found to be the most dense and highest porous morphology asymmetric Psf MMM. The retained percentage of Cu and flux for M6 attained the highest value of 80.3% and 136.99 L/m2 .h respectively, whereas for the neat Psf membrane, M0 exhibited the lowest retained percentage of Cu and flux, about 25.8% and 61.64 L/m2.h. The inclusion of pore former and additives has shown an improvement of 54.5% in the copper rejection. Moreover, M6 displayed the highest antifouling properties compared to other Psf MMMSs. This study proves that PEG and TiO2 additives have significant potential to improve membrane performance due to the highest percentage of Cu retained on the surface of the membrane as adsorptive separation on Psf MMMs.

Green synthesis of ZnO, Fe3O4, and TiO2 nanoparticles: exploring enhanced bacterial inhibition, catalysis, and photocatalysis for sustainable environmental applications

ABSTRACT This study investigates the physicochemical and biological properties of metal oxide nanoparticles (TiO2, ZnO, and Fe3O4) synthesised via the phytosynthesis method using an extract from Boerhaavia diffusa leaves (BDL). The proteins and phenols present in the BDL extract played essential roles in reducing and stabilising TiO2, ZnO, and Fe3O4 nanoparticles. The study reveals size-dependent morphological, structural, and biological characteristics of the produced nanoparticles. FTIR spectra confirm the involvement of BDL extract in the synthesis process of TiO2, ZnO, and Fe3O4 nanoparticles. Transmission electron microscopy (TEM) analysis of TiO2 nanoparticles identified small, spherical particles (9 nm in diameter). BDL-derived TiO2, ZnO, and Fe3O4 demonstrated significant photocatalytic activity, achieving degradation rates of 98.96%, 96.26%, and 94.42%, respectively, in the decomposition of mono-azo dye after 40 minutes of UV irradiation. The reaction rates for BDL-derived TiO2, ZnO, and Fe3O4 were 0.367/min, 0.186/min, and 0.061/min, respectively, when catalysing the reduction of 4-Nitrophenol (4-NP) to 4-Aminophenol using NaBH4. BDL-derived TiO2 nanoparticles exhibited significant antibacterial effectiveness, showing a 23.6 mm zone of inhibition against Salmonella typhi. The BDL-derived TiO2, ZnO, and Fe3O4 nanoparticles exhibited remarkable cytotoxicity against lung cancer cell lines with IC50 values of 76.36 µg/mL, 90.21 µg/mL, and 94.61 µg/mL, respectively. This study reveals the potential of BDL-derived TiO2, ZnO, and Fe3O4 nanoparticles for applications in antibacterial, anticancer, catalytic, and photocatalytic fields, contributing to sustainable development of multifunctional nanomaterials for various technical and environmental advancements.

Natural convection magneto hydrodynamic filled with TiO2 nanofluid with a right-angled triangle obstacle within square cavity

The goal of this study is to examine the result of natural convection, magnetohydrodynamics, and nanofluids within a square cavity with an obstacle of a right-angle triangle within it. Among the various nanoparticles, TiO2 nanoparticles blended with water have shown promise in improving heat transfer. The Finite Element Method is used for the simulation. By utilizing the commercial software 'COMSOL Multiphysics 6.1' graphical illustrations, the influence of prominent parameters on streamline, isotherm contours and the local Nusselt number is effectively portrayed. The key factors that play a dominant role include the Prandtl number (Pr = 6.2) and Rayleigh number (104 <= Ra <= 106), Hartmann number (Ha = 0, 30, 50), and the heat source/sink (Q = -6, 0, 6) employed. The result confirms that the decline in fluid velocity and convective heat transfer is due to the enhancement of the Lorentz force. This outcome of the study affirms that the appropriate amalgamation of nanoparticles significantly improves the transmission of heat properties of fundamental fluids. The discoveries of this investigation could aid in comprehending the hydrothermal aspects of thermal systems, including electronic cooling, solar power and the utilization of nanofluid to regulate liquid movement and thermal exchange attributes within the annular space.

Synergistic Effect of Sn Doping in TiO2 Nanoparticles as an Additive in Anti‐Corrosion Coatings

ABSTRACTCorrosion is a major problem and protective coatings offer an effective solution. However, organic coatings are often associated with microcracks caused by the evaporation of solvents during coating preparation. This study investigates the use of titanium dioxide (TiO2) nanoparticles as a coating additive to protect mild steel surfaces. Additionally, doping TiO2 with tin (Sn) is believed to enhance its properties due to the reduced size of the nanoparticles. These nanoparticles were synthesised using the sol–gel method and subjected to various analyses. The coated mild steel samples were prepared using the dip‐coating method and immersed in 3.5 wt.% sodium chloride (NaCl) solution for 30 days. Electrochemical impedance spectroscopy (EIS) and Tafel polarisation showed that the Sn‐doped TiO2 nanoparticles as an additive improved the corrosion resistance, as evidenced by a positive shift in corrosion potential (Ecorr) and reduced corrosion current density (Icorr).

Mycosynthesis of TiO2 nanoparticles using Aspergillus penicillioides for toxic metal removal and photocatalytic applications

Globally, heavy metal pollution, especially lead and nickel, is becoming a problem and is of great concern due to its adverse effects. This study focuses on the eco-friendly biosynthesis of TiO2 nanoparticles using Aspergillus penicillioides metabolites as capping and reducing agents. The myco-synthesized TiO2 nanoparticles were characterized as oblate spherical and applied for photocatalytic removal of lead and nickel from industrial effluent. Optimal conditions for removal included lead and nickel concentrations of 60 μg/mL and 2 μg/mL, 10 μg/mL TiO2 nanoparticle concentration, a pH of 6, and sunlight irradiation. The kinetics and isotherm of adsorption were explained. Effective degradation of lead and nickel by using TiO2 nanoparticles was confirmed by atomic absorption spectroscopy. The nanoparticles demonstrated effective photocatalytic degradation of crystal violet dye achieved a high of 86.9% in 4h and 25% in 2 h, respectively, and showed promising biological activities, including antibacterial, antioxidant, and protein leakage properties. The hemolytic assay confirmed their ecological sustainability for bioremediation. The study highlights the effectiveness of new bio-based TiO2 nanoparticles arbitrated by Aspergillus penicillioides as effective bioremediation agents.

H2O2-assisted room temperature preparation of crystalline TiO2 and Ti3C2Tx-derived C-doped amorphous TiOx homojunction for photocatalytic degradation of tetracycline

The light absorption, active sites, and charge carriers separation of photocatalysts are extremely important factors in the field of photocatalysis. Near-perfect lattice-matched homojunction constructed using disorder engineering and doping strategies is an effective strategy to improve photocatalytic activity. Herein, we developed crystalline TiO2 nanoparticles (NPs) and Ti3C2Tx MXene-derived C-doped amorphous TiOx homojunction (TCT) at room temperature. In this homojunction, TiO2 NPs are evenly distributed on the surface of the C-TiOx nanosheet to form a type-II structure, which promotes the separation of photogenerated carriers. The light absorption range of TCT extends to 550 nm due to the presence of intermediate energy levels in C-TiOx, which increases its photon absorption capacity. Moreover, TCT possesses a large number of oxygen vacancies, which are beneficial for improving the adsorption and degradation of pollutants. These characteristics of TCT could significantly improve its photodegradation performance for tetracycline. Interestingly, the precursor mass ratio of TCT with the best degradation efficiency is different under different illumination conditions, which is attributed to the different band gaps of C-TiOx and TiO2 NPs resulting in different light absorption ranges. This work provides a new approach to rationally designing crystalline and amorphous homojunction for photocatalytic applications.

Novel cytotoxicity of nano-coated orthodontic micro-implants: An in vitro study

Objectives: Many attempts have been made to modify the surface of orthodontic micro-implants and prevent the development of microbes by coating them with antimicrobial nanoparticles (NPs). The purpose of the present study was to evaluate the cytotoxicity of different NPs, namely, TiO2 and zinc oxide (ZnO) NPs, that are used to coat titanium orthodontic micro-implants. Material and Methods: Thirty orthodontic micro-implants were included in this study. Those were divided into three groups: control group without coating, TiO2-coated orthodontic micro-implants, and TiO2- and ZnO-coated orthodontic micro-implants. Scanning electron microscope, energy-dispersive spectroscopy (EDS), and cytotoxicity tests were applied for all groups. Results: The results of scanning electron microscopy and EDS showed effective deposition of the titanium oxide layer onto the micro-implants. The ZnO layer applied on the micro-implants exhibited superior physicochemical characteristics in comparison to the uncoated samples with no significant cytotoxicity. Conclusion: Both NPs showed biocompatibility with the oral tissues.

“Synthesis and characterization of TiO2 nanoparticles as brake fluid additives: Viscosity modulation and impact on rheological properties”

TiO2 nanoparticles were synthesized using the reduction precipitation method, verified by powder x-ray diffraction (PXRD) with an average crystallite size of 62 nm and an average particle size of 135 nm from SEM images. Rheological studies of brake fluid with nanoparticle additives revealed that while the fluid generally maintains consistent behavior, a 2 wt.% concentration showed non-Newtonian behavior at 120 °C. Viscosity increased slightly with nanoparticle addition and decreased with rising temperature, with the 0.5 wt.% sample demonstrating the most notable increase of 18.18% at 120 °C. At 30 °C, the 1 wt.% sample exhibited a 4.06% increase. The observed viscosity changes are attributed to higher internal shear stress and the need to manage dispersion solid elements. The Herschel-Bulkley model was effective in predicting sample behavior, and all samples conformed to Reynolds’ equation μ 0 = b e − aT . This research indicates that TiO2 nanoparticles can be effectively used as brake fluid additives, offering potential benefits for high-temperature applications in vehicles. Further optimization using mathematical models such as response surface methodology (RSM) is suggested for improved performance.

Engineering hierarchical TiO2/ZnIn2S4 hybrid heterostructure with synergistic interfaces: A dual-functional S-scheme photocatalyst for efficient CO2 reduction and norfloxacin degradation

The development of multifunctional photocatalysts that can harness solar energy for both environmental remediation and energy generation is a considerable challenge in achieving sustainable development. This study introduces a dual-functional S-scheme hybrid catalyst comprising hierarchical 3D flower-like ZnIn2S4 (ZIS) microspheres embedded with TiO2 (TO) nanoparticles, synthesized via a facile in situ hydrothermal process. The unique structural and compositional synergy between ZIS and TO leverages their complementary photocatalytic properties, facilitating efficient solar energy utilization, increasing specific surface area, and enhancing CO2 adsorption capabilities. The S-scheme mechanism, confirmed by in situ-irradiated X-ray photoelectron spectroscopy and electron spin resonance spectroscopy, underlying this system promotes effective separation of photoexcited charge carriers while preserving the intrinsic strong reducibility of ZIS and high oxidizability of TO. These beneficial properties of the TO/ZIS hybrid provide a robust platform for CH4 production (75.6 μmol h−1 g−1) through selective (99.6 %) CO2 reduction over competing water reduction and achieve exceptional degradation and mineralization of the persistent antibiotic norfloxacin in water, addressing both energy and environmental challenges. Furthermore, the hybrid catalyst exhibits significant stability and recyclability, maintaining high catalytic performance across multiple cycles, thereby underscoring its practical viability. This work offers a promising blueprint for developing multifunctional photocatalysts capable of addressing critical global challenges, demonstrating the potential of hierarchical nanostructures and S-scheme charge transfer mechanisms.

Singlet Oxygen Photocatalytic Generation by Silanized TiO2 Nanoparticles.

A commercial TiO2 sample, used as received or hydrothermally treated to increase surface hydroxylation, has been functionalized by surface modification with hexadecyltrimethoxysilane. The anchoring of thesilane has been characterized byFTIR and solid-state NMR spectroscopies, and the grafting density was determined by thermogravimetric and N2 physisorption analyses. The silane moieties induce a partial decrease of the shielding of the valence electrons of the Ti ions at the surface, and a local modification of their crystal field, as demonstrated by XPS and UV-vis spectroscopy, respectively. The changes in coordination and the produced oxygen vacancies result in the formation of Ti3+ defects localized in the sub-surface region, as revealed by EPR spectroscopy. These paramagnetic centers are stabilized in the silanized samples, as the electron transfer to O2 is efficiently inhibited even under UV irradiation. However, the amount of Ti3+ centers appears to be correlated with the singlet oxygen (1O2) formation rate. Accordingly, epoxidation of limonene under UV light, chosen as a model photocatalytic reaction triggered by 1O2, occurred with higher selectivity when TiO2 was silanized and upon simultaneous NIR irradiation. These evidences suggest that in the silanized sample 1O2 may be generated through Förster-type energy transfer from excited sub-surface Ti3+ centers.

Synergistic and antagonistic interaction between ZDDP and TiO2 nanoparticles under boundary lubrication

Lubricants are complex mixtures of additives that serve multiple purposes, and these additives must work synergistically at best and at worst, not interfere with each other. In previous research, nanoparticles of TiO2 have demonstrated excellent tribological outcomes when used singularly as an additive in lubricants. In this study, we have shown that when nanoparticles of TiO2 and ZDDP are used together they act antagonistically by resulting in very high wear rates wherein nanoparticles of TiO2 remove the protective tribofilms from ZDDP as they form on the surface. To further investigate this behavior, we used these additives in alternating sequential order and introduced them at different time points (15 & 30 min) during the one-hour testing. Very synergistic interaction is seen when TiO2 is used first followed by ZDDP wherein the TiO2 reacts with the Fe substrate to form FeTiO3. This layer then serves as a superior surface for Zn-polyphosphates and Ti-phospate tribofilms formed due to the decomposition of ZDDP under tribological conditions. On the other hand, when use of ZDDP is followed by TiO2 we see outcomes that favor the shorter duration of use of ZDDP, however, results are not as effective as former case where TiO2 is followed by ZDDP. The addition of TiO2 earlier in the tribological process assists in the development of more robust complex polyphosphate tribofilms leading to much desirable tribological properties.

Antibiofilm Activity of PDMS/TiO2 against Candida glabrata through Inhibited Hydrophobic Recovery.

Coatings with antibiofilm properties are desirable for biomedical applications. Titanium dioxide (TiO2) has been explored as an antimicrobial agent in materials development primarily due to it being an excellent photocatalyst. Candida glabrata (C. glabrata) is an emerging human fungal pathogen with known high resistance to oxidative stress. Here, we fabricated a polydimethylsiloxane/titanium dioxide (PDMS/TiO2) nanocomposite coating and tested its antibiofilm activities against C. glabrata. The resulting nanocomposite exhibited >50% reduction in C. glabrata biofilm formation with 2.5 wt % TiO2 loading, even in the dark. Through ROS detection and surface characterization, the antibiofilm activity was attributed to the synergistic interaction of TiO2 nanoparticles with the PDMS matrix, which resulted in the impediment of hydrophobic recovery. This work provides a design strategy to develop antibiofilm coatings against C. glabrata.

Characterization of exopolysaccharide / starch composite film incorporated with TiO2 nanoparticles and its application in chilled meat preservation

Multifunctional food packaging composite films were prepared using Pediococcus acidilactici J1 exopolysaccharide (EPS), potato starch (PS) and TiO2 nanoparticles by casting method. The microstructure, physicochemical properties and antibacterial activity of EPS/PS composite films with different weight ratio of TiO2 nanoparticles were characterized. Transmission electron microscope (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed the uniform distribution of TiO2 nanoparticles in the EPS/PS matrix. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results indicated that the interaction between polymers and nanoparticles through non-covalent bonds. When TiO2 nanoparticles were added at 1 % (wt), the composite film had higher barrier properties against water vapor and UV–vis light, and better mechanical properties then EPS/PS film. Notably, EPS/PS/1%TiO2 composite film exhibited good antioxidant and antibacterial activity against Escherichia coli and Staphylococcus aureus. Through the analysis of the quality indexes and microbial community structure during the storage of chilled meat, the composite film slowed the oxidation rate of chilled meat and inhibited the growth of dominant spoilage bacteria, effectively extending its shelf life. All results suggested that EPS/PS/1%TiO2 composite film could serve as an effective packaging material for chilled meat, providing a novel approach to solve its limited shelf-life problem.

A versatile superhydrophilic/air-superoleophobic glass fiber membrane: Fabrication and application in oil/water separation

Superwetting materials have received extensive interest owing to their potential for efficient oil/water separation. Herein, a superhydrophilic-superoleophobic glass fiber membrane was fabricated through a simple spraying coating method. The membrane was coated with a composite layer of methyltrimethoxysilane (MTMS), fluorosurfactant (FS-50) and TiO2 nanoparticles. Accordingly, both hydrophilic groups (i.e., -OH) and oleophobic groups (i.e., fluorinated groups) were distributed on the membrane, and its surface roughness was improved by TiO2. The contact angles of water and oil on the coated membrane were 0° and 156.8° in air, respectively. By virtue of its selective permeability, it demonstrated separation efficiencies larger than 99.2 % for oil/water mixtures, which remained 98.7 % after 40 separation cycles. Furthermore, its separation efficiencies for oil-in-water emulsions were over 98.3 %, which remained 98 % after 10 separation cycles. Owing to its strong superoleophobicity, it displayed prominent anti-oil-fouling performance both in air and underwater. Besides, presence of TiO2 endowed it with photocatalytic capability, enabling it to recover from organic dye pollution. Moreover, the coated membrane maintained superoleophobic after 10 sandpaper-abrading or squeezing cycles. It also exhibited excellent stability under acid/alkali/salt conditions. The study provided new insights for constructing superwetting materials and an effective strategy for oil/water separation.

Icelike water molecules with single hydrogen bond donor on the surface of nano anatase and rutile particles by IR spectroscopy

The hydration behavior of TiO2 nanoparticles was studied by molecular dynamics simulations and a novel IR ratio spectroscopy method. It was found that the hydration water at the titanium dioxide interface contains molecules with a large number of single hydrogen bond donors, and approximately five water layers were confined within the nano-grooves of the nanoparticles. The confinement effect was observed to enhance the strength of the hydrogen bonds and to slow down the movement of the water molecules around the surface of the nanoparticles.

Harnessing the potential of electrospun TiO2 nanofibers and nanoparticles enriched with natural dyes: a path towards affordable aolutions for low-cost electronic devices

Abstract This study evaluates the morphological effects of TiO2 nanoparticles, nanofibers, and a bilayer configuration on electronic devices, such as Dye-Sensitized Solar Cells (DSSCs) and UV sensors. Cost-efficient natural dyes—curcumin, coffee beans, and banana peel—were used as sensitizers for nanomaterial films. TiO2 nanoparticles were synthesized using the sol–gel technique, while nanofibers were produced via electrospinning. Characterization techniques, including Scanning Electron Microscopy (SEM), Energy Dispersive x-ray Spectroscopy (EDS), and x-ray Diffraction (XRD), confirmed the formation and dimensions of the TiO2 nanostructures. UV–visible spectroscopy was used to determine the optical properties of the samples. TiO2 nanofibers and nanoparticles exhibited high surface-area-to-volume ratios, with nanofibers having a diameter of 20 nm and particles measuring 50 nm. A binder-free, low-temperature paste was prepared using TiO2 nanoparticles and nanofibers to develop thin films. The turmeric dye showed peak absorption at 470 nm with a band gap energy of 2.06 eV when loaded on a TiO2 bilayer film. This study aims to develop electronic devices that reduce costs and enhance performance by using low-cost, efficient, and economically viable dyes. TiO2 nanofiber and nanoparticle films show promise for cost-effective and high-performance electronic devices.

Hepatoprotective Activity of Gingko biloba‐Mediated TiO2 NPs Against Acetaminophen‐Induced Albino Rats‐ In Vitro Studies

AbstractNumerous effects of “titanium dioxide nanoparticles (TiO2 NPs)” have been described and significantly utilized in complementary drugs for many decades. This study is conducted to analyze the therapeutic efficiency of TiO2 NPs against the acetaminophen‐(AMP) induced toxicity. TiO2 NPs were initially prepared using Ginkgo biloba leaf extract as reducing and stabilizing agent. The prepared TiO2 NPs were studied using various spectroscopic and microscopic techniques. AFM, TEM, XRD, and DLS studies have confirmed the formation of TiO2 NPs with size between 20 to 60 nm with negative surface charge of about −12 mV. Later, hepatoprotective studies were performed by administering AMP to albino mice only once at a dosage of 2 g/kg p.o. Post 24 h of AMP intoxication, the animals were treated orally with three different doses of TiO2 NPs (150, 100, and 50 mg/kg) or silymarin at an amount of 50 mg/kg p.o., administered only once. Post 24 h of last treatment, all the animals were surrendered to death. The group of mice administered with AMP displayed a substantial raise in the serum alkaline phosphatase (560 ± 31.90), lactate dehydrogenase (167 ± 10.17), aspartate amino transferase (251 ± 14.82), alanine amino transferase (326 + 18.96), bilirubin (2.2 ± 1.066), cholesterol (96.7 ± 6.2), and albumin (6.0 ± 1.27) in serum, which signified the liver damage. A considerably depleted level of glutathione (5.4 + 1.24) was detected in the mice intoxicated with AMP. The activities of catalase (33.2 ± 2.66) and superoxide dismutase (36 ± 2.93) declined after exposure to acetaminophen, resulting in oxidative stress in liver. The performance of adenosine triphosphatase (901 ± 50.7) and glucose‐6‐phosphatase (3.9 + 1.15) were considerably inhibited after administrating with AMP. On treating with TiO2 NPs, all the variables reversed significantly towards regular levels and were noticed to be nontoxic. The groups treated with TiO2 NPs exhibited less activity of ALT, AST, LDH, and SALP in serum, indicating the protective effect of TiO2 NPs to prevent liver damage. Exposure with TiO2 NPs inverted the cholesterol, albumin, and bilirubin levels towards normal, which is similar to silymarin treatment. TiO2 NPs exhibited a substantial change in tissue and blood biochemical parameters with that of control groups. These results indicate that TiO2 NPs possesses hepatoprotective properties that mitigate the hepatotoxicity induced by acetaminophen in rats. Hence, TiO2 NPs can be further utilized in the preparation of medicine against hepatic and renal diseases, post further clinical and preclinical studies.

A multi-omics approach reveals differences in toxicity and mechanisms in rice (Oryza sativa L.) exposed to anatase or rutile TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in agriculture, which increased the risk to soil-plant systems. Studies have demonstrated that TiO2 NPs can induce phytotoxicity. However, the toxicity mechanisms, particularly under the stress of TiO2 NPs with different crystalline forms, remain inadequately reported. In this study, we combined transcriptomics and metabolomics to analyze the toxicity mechanisms in rice (Oryza sativa L.) under the stress of anatase (AT) or rutile (RT) TiO2 NPs (50 mg/kg, 40 days). The length (decreased by 1.1-fold, p = 0.021) and malondialdehyde concentration (decreased by 1.4-fold, p = 0.0027) of rice shoots was significantly reduced after AT exposure, while no significant changes were observed following RT exposure. Antioxidant enzyme activities were significantly altered both in the AT and RT groups, indicating TiO2 NPs induced rice oxidative damage (with changes of 1.1 to 1.4-fold, p < 0.05). Additionally, compared to the control, AT exposure altered 3247 differentially expressed genes (DEGs) and 56 significantly differentially metabolites in rice (collectively involved in pyrimidine metabolism, TCA cycle, fatty acid metabolism, and amino acid metabolism). After RT exposure, 2814 DEGs and 55 significantly differentially metabolites were identified, which were collectively involved in fatty acid metabolism and amino acid metabolism. Our results indicated that AT exposure led to more pronounced changes in biological responses related to oxidative stress and had more negative effects on rice growth compared to RT exposure. These findings provide new insights into the phytotoxic mechanisms of TiO2 NPs with different crystalline forms. Based on the observed adverse effects, the study emphasizes that any form of TiO2 NPs should be used with caution in rice ecosystems. This study is the first to demonstrate that AT is more toxic than RT in paddy ecosystems, providing crucial insights into the differential impacts and toxic mechanisms of TiO2 NPs with different crystalline forms. These findings suggest prioritizing the use of RT when TiO2 NPs are necessary in agricultural development to minimize toxicity risks.

Enhanced hydrophobic properties, wear and corrosion resistance of plasma electrolyte oxidation coatings on AZ31B magnesium alloys with addition of TiO2 nanoparticles

Nanocomposite coatings were fabricated on AZ31B magnesium alloy by means of plasma electrolyte oxidation (PEO) with the addition of TiO2 nanoparticles into the alkaline electrolyte, followed by low surface energy modification in the ethanol solution of lauric acid. The dual-layered nanocomposite PEO coatings composed of MgO, Mg2SiO4, anatase-TiO2, rutile-TiO2, and Mg2TiO4 were formed, and the TiO2 nanoparticles incorporated into the PEO coatings via both inertia and reactive modes. Besides, the penetration and adsorption of TiO2 nanoparticles created a distribution gradient in the coating thickness direction. The wear rate of the PEO coatings with TiO2 nanoparticles in 4 g/L was approximately 82 % lower than that of the bare substrate and approximately 39 % lower than that of the PEO coatings without TiO2 addition, respectively. The enhancement in wear resistance was due to the synergistic effect of the lower coefficient of friction (COF), the higher microhardness and the denser microstructure with finer micropores and less microcracks on the coatings than that of the TiO2-free coatings. Besides, the hydrophobic property was enhanced for the low surface energy modified PEO coatings with the addition of TiO2 nanoparticles in the electrolyte. Moreover, a significant enhancement in the corrosion resistance was achieved for the PEO coating with the addition of TiO2 nanoparticles in 4 g/L. It exhibited a higher corrosion inhibition efficiency and a lower corrosion rate than that in other concentrations and without TiO2 addition. The improvement in anti-corrosion property was originated from the formation of phases including TiO2 and Mg2TiO4 in the coating, and denser microstructure with better hydrophobic properties for the PEO coatings with TiO2 nanoparticles in 4 g/L compared with that in other concentrations. Accordingly, the hydrophobic, wear-resistant and corrosion-resistant PEO coatings with TiO2 nanoparticles exhibited significant advantages in the field of Mg alloys protection.