Search Results (274)

Nanofertilizers (NFs) and engineered nanoparticles (NPs) are increasingly used in agriculture, yet their environmental safety remains poorly understood. This study evaluated the comparative phytotoxicity of zinc oxide (ZnO), titanium dioxide (TiO₂), and clinoptilolite nanoparticles, three commercial nanofertilizers, and potassium dichromate (K₂Cr₂O₇) using Lactuca sativa seeds under adapted OECD-208 protocol conditions. Seeds were exposed to varying concentrations of each xenobiotic material (0.5–3% for NFs; 10–50% for NPs), with systematic assessment of seedling survival, root and hypocotyl length, dry biomass, germination index (GI), and median effective concentration (EC₅₀) values. Nanofertilizers demonstrated significantly greater phytotoxicity than engineered nanoparticles despite lower application concentrations. The toxicity ranking was established as NF1 > NF3 > NF2 > NM2 > NM1 > NM3, with NF1 being most toxic (EC₅₀ = 1.2%). Nanofertilizers caused 45–78% reductions in root length and 30–65% decreases in dry biomass compared with controls. GI values dropped to ≤70% in NF1 and NF3 treatments, indicating concentration-dependent growth inhibition. While nanofertilizers offer agricultural benefits, their elevated phytotoxicity compared with conventional nanoparticles necessitates rigorous pre-application safety assessment. These findings emphasize the critical need for standardized evaluation protocols incorporating both physiological and ecotoxicological endpoints to ensure safe xenobiotic nanomaterial deployment in agricultural systems. Full article

Ecotribology focuses on both saving energy resources and reducing environmental pollution. Considering environmental concerns, water-based nanolubricants have gained significant attention over conventional oil-based ones. Non-ecotoxic and highly environmentally friendly nanoadditives were chosen for nanolubricant synthesis, especially considering their use at elevated temperatures. In this study, hexagonal boron nitride nanosheets (hBNNSs) and titanium dioxide nanoparticles (TiO₂ NPs) were used to prepare water-based lubricants with glycerol and surfactant sodium dodecyl benzene sulfonate (SDBS) in water under ultrasonication. An Rtec ball-on-disk tribometer was used to investigate the tribological performance of the synthesised water-based lubricants containing different nano-hBN/TiO₂ concentrations, with dry and water conditions used as benchmarks. The results indicated that the water-based nanolubricant containing 0.5 wt% hBN and 0.5 wt% TiO₂ exhibited the best tribological performance at both ambient (25 °C) and elevated (500 °C) temperatures. This optimal concentration leads to a reduction in the coefficient of friction (COF) by 72.9% and 37.5%, wear of disk by 62.5% and 49%, and wear of ball by 74% and 69% at ambient and elevated temperatures, respectively, compared to that of distilled water. Lubrication mechanisms were attributed to the rolling, mending, tribofilm, solid layer formation, and synergistic effects of hBNNSs and TiO₂ NPs. Full article

Titanium dioxide (TiO₂), a widely used semiconductor in photocatalysis owing to its adequate potential for water hydrolysis, chemical stability, low toxicity, and low cost. However, its efficiency is limited by fast charge-carrier recombination and poor visible light absorption. Coupling TiO₂ with a p-type semiconductor, such as nickel oxide (NiO), forming a p-n heterojunction, decreases the recombination of charge carriers and increases photocatalytic activity. In this work, the surface of TiO₂ modified with NiO nanoparticles (NPs) induced by radiolysis for photocatalytic hydrogen production was studied. The photocatalytic activity of NiO/TiO₂ was evaluated using methanol as a hole scavenger under UV–visible light. All modified samples presented superior photocatalytic activity compared to bare TiO₂. The dynamics of the charge carriers, a key electronic phenomenon in photocatalysis, was investigated by time-resolved microwave conductivity (TRMC). The results highlight the crucial role of Ni-based NPs modification in enhancing the separation of the charge carrier and activity under UV–visible irradiation. Furthermore, the results revealed that under visible irradiation, NiO-NPs inject electrons into the conduction band of titanium dioxide. Full article

The accumulation of nanoparticles (NPs) in the female body has raised global concerns regarding potential effects on the reproductive system. This study aimed to investigate the toxic effects of nano-titanium dioxide (nano-TiO₂) exposure on the ovaries and the underlying mechanisms. By establishing a nano-TiO₂ accumulation model in mice, our research systematically evaluated the effects of different concentrations of nano-TiO₂ exposure on the development and reproductive endocrine functions of mice. The results showed that nano-TiO₂ exposure significantly reduced the littering rate, sex hormone levels, and ovarian index of mice, and the effects were dose-dependent. Studies on the mechanisms involved revealed that nano-TiO₂ induces an excessive production of reactive oxygen species (ROS), leading to the potential collapse of the mitochondrial membrane and an increase in the apoptosis rate of granulosa cells, thereby triggering oxidative stress and inhibiting the expression of ovarian-specific genes and granulosa-cell function genes. This study reveals the “dual blow” mechanism of nano-TiO₂-mediated ovarian morphology and function through oxidative stress in granulosa cells, namely directly disrupting cellular homeostasis and interfering with the reproductive-related gene network, ultimately leading to decreased ovarian function. This provides experimental evidence for assessing the reproductive risks of nanomaterials in women. Full article

The dry roots of Polygonum cuspidatum contain resveratrol, a compound known for its antimicrobial and protective effects against oxidative stress, which is associated with impaired wound healing. In this study, titanium dioxide nanoparticles (TiO₂NPs) were loaded with a P. cuspidatum extract (TiO₂-loaded extract NPs), and the resveratrol release profile, hemocompatibility, antioxidant, cytotoxic, and antimicrobial activities were evaluated. The results demonstrated that TiO₂-loaded extract NPs exhibited antioxidant activity for DPPH (Inhibitory Concentration 50 (IC₅₀) = 62.31 mg Trolox Equivalent (TE)/mL) and ABTS⁺ (IC₅₀ = 4.8 mg TE/mL) assays, along with suitable hemocompatibility (3.02% at 10 mg/mL), in comparison with bulk TiO₂ NPs. Additionally, temperature influenced the resveratrol release over time. The P. cuspidatum extract alone showed strong antibacterial activity, with a Minimal Inhibitory Concentration (MIC) of 5 µg/mL, TiO₂-loaded extract NPs showed MIC values about 50 mg/mL, while bulk TiO₂ NPs exhibited no antibacterial effect against the tested strains. In contrast, the P. cuspidatum extract, the TiO₂-loaded extract NPs, and the bulk TiO₂ NPs did not demonstrate antifungal activity against Candida albicans and C. glabrata. Moreover, TiO₂-loaded extract NPs showed no cytotoxicity against the L-929 cell line at concentrations ranging from 1.5 to 150 µg/mL, unlike TiO₂ NPs, which exhibited high cytotoxic concentrations between 9.4 and 300 µg/mL. These findings suggest that TiO₂-loaded extract NPs effectively control the release of resveratrol and hold promises for applications in skin management and wound healing. Full article

Titanium dioxide nanoparticles (TiO₂-NPs) were synthesized using the molten salt method and systematically characterized. TiO₂-NPs were evaluated for their capacity to promote the growth of Capsicum annuum cultivars together with the plant growth-promoting microorganisms (PGPMs) Bacillus thuringiensis (Bt) and Trichoderma harzianum (Th). The variables analyzed included physiological parameters and antioxidant responses. The capacity of TiO₂-NPs to scavenge free radicals was also investigated, along with their biocompatibility, using Artemia salina as an in vivo model. The results demonstrated that TiO₂-NPs exhibited a nanocuboid-type morphology, negative surface charge, and small surface area. It was noted that TiO₂-NPs enhanced the CFU and spore production of Bt (1.56–2.92 × 10⁸ CFU/mL) and Th (2.50–3.90 × 10⁸ spores/mL), respectively. It was observed that TiO₂-NPs could scavenge DPPH, ABTS, and H₂O₂ radicals (IC₅₀ 48.66–109.94 μg/mL), while not compromising the viability of A. salina at 50–300 μg/mL. TiO₂-NPs were determined to enhance the root length and fresh and dry weights of chili peppers. Similarly, TiO₂-NPs in synergy with Bt and Th increased the activity of β-1,3-Glucanase (2.45 nkat/g FW) and peroxidase (69.90 UA/g FW) enzyme activity, and increased the TPC (29.50 GA/g FW). The synergy of TiO₂-NPs with the PGPMs consortium also upregulated the total chlorophyll content: 210.8 ± 11.4 mg/mg FW. The evidence from this study unveils the beneficial application of TiO₂-NPs with Bt and Th as an efficient approach to promote the physiology and antioxidant responses of chili peppers. Full article

Nanotechnology is an emerging field in science that exhibits significant promise in the synthesis of nanomaterials for diverse applications. Traditionally, these nanomaterials were manufactured using hazardous and labor-intensive physical and chemical processes. Nevertheless, in recent years, researchers have developed safer, more scalable, and environmentally friendly methods for green synthesis. The problem addressed in this study is the need for an environmentally friendly and efficient synthesis process for titanium dioxide nanoparticles (TiO₂ NPs) with enhanced properties. The aim of this work is to describe the synthesis of TiO₂ NPs with various plant extracts using a green approach and to evaluate the physicochemical characteristics and potential applications of the resulting nanoparticles. This study focuses on understanding how the integration of plant extracts influences the properties of TiO₂ NPs, particularly in terms of their structural, optical, and functional characteristics. The novelty lies in the use of plant extracts as bio-reductants and capping agents, which not only provides a safer and more sustainable synthesis method but also enhances the functional properties of TiO₂ NPs. This green synthesis approach reduces the use of harmful chemicals, making the process more environmentally friendly and economically viable, with potential applications in photocatalysis, antibacterial, and antioxidant activities. The TiO₂ NPs possess diverse functionalities, including photocatalysis, antibacterial properties, and antioxidant properties. The initial precursor, such as a metal salt, undergoes transformation into the desired nanoparticles through the actions of plants exactly. Bio-reduction and capping processes are carried out by secondary metabolites found in bacteria and plants. The results demonstrated that the plant extract-mediated TiO₂ NPs exhibited enhanced photocatalytic activity, superior antibacterial effects, and higher antioxidant potential compared to chemically synthesized TiO₂ NPs. This highlights the potential of green synthesis methods in producing nanomaterials with improved functional properties for a wide range of applications. Full article

Titanium dioxide (TiO₂) is one of the most widely produced nanomaterials. Many products contain nanoparticles because they have various technological, medical, and economic benefits. However, the presence of nanoparticles in the environment has a negative impact on public health. Due to the presence of TiO₂ NPs in food, food packaging, and drinking water, they can easily enter the human gastrointestinal tract (GIT), which includes environments with different pH values. These pH changes can affect the stability, dispersion, and toxicity of nanomaterials. Our experiments aimed to monitor the effect of TiO₂ NPs incubated at a pH similar to the GIT values on DNA structure. DNA damage was monitored using a DNA biosensor and a biosensing approach with electrochemical voltammetric detection. Cyclic voltammetry (CV) detected damage to DNA/GCE biosensors of up to 10%. The best way to monitor the genotoxicity of TiO₂ NPs on DNA structure was the biosensing approach, which changes in the redox indicator current response detected by differential pulse voltammetry (DPV) up to 47.6%. The highest effect of TiO₂ was observed for guanine residues at pH 8.0. The results were confirmed by UV–vis spectrophotometry and hyperchromic and bathochromic spectral shifts. Full article

Evaluating the effects of nanoparticles on biomass growth and astaxanthin accumulation in Haematococcus lacustris is crucial for optimizing the production of astaxanthin, a valuable carotenoid with numerous industrial applications. Identifying the life stages at which these nanoparticles exert stimulatory or toxic effects will aid in formulating effective production strategies. This study investigated the effects of titanium dioxide (TiO₂), zinc oxide (ZnO), and copper oxide (CuO) nanoparticles on biomass growth, astaxanthin biosynthesis, and lipid accumulation in Haematococcus lacustris, with a focus on their stage-specific impact throughout the algal life cycle. The nanoparticles were added at the start of cultivation, and the microalgal cultures developed continuously in their presence. Sampling for biochemical analyses was performed at distinct life stages (green motile, palmella, and aplanospore), enabling the assessment of stage-dependent responses. TiO₂NPs significantly stimulated biomass accumulation during the green motile stage. In the palmella stage, astaxanthin levels decreased in the presence of all nanoparticles, likely due to the absence of a stress signal required to activate pigment biosynthesis, despite ongoing biomass growth. In contrast, the aplanospore stage exhibited reactivation of astaxanthin biosynthesis and increased lipid accumulation, particularly under TiO₂NPs. Astaxanthin content increased by 21.57%. This study highlights that TiO₂, ZnO, and CuO nanoparticles modulate growth and astaxanthin biosynthesis in Haematococcus lacustris in a life cycle-dependent manner. Full article

This research investigates the enhanced photocatalytic activity of cuprous oxide (Cu₂O) nanoparticles (NPs)-titanium dioxide (TiO₂) nanotube (NT) composites for air purification, focusing on the removal of volatile organic compounds (VOCs) and Escherichia coli (E. coli) bacteria under simulated sunny light. Cu₂O-NPs were successfully deposited onto TiO₂-NTs via the successive ionic layer adsorption and reaction method. The resulting p- and n-type semiconductor heterojunction nanocomposites were characterized using various techniques, including scanning electron microscopy, transmission electron microscopy, ultraviolet–visible-light spectroscopy, and chlorinated radicals. The photocatalytic activity was evaluated for different VOCs present in indoor air (butadione, chloroform, and butyraldehyde) in the presence of E. coli bacteria. The results showed that the Cu₂O-NPs/TiO₂-NTs composites exhibited enhanced photocatalytic activity compared to pure TiO₂-NTs. The Langmuir–Hinshelwood model was used to describe the degradation kinetics, revealing that Cu₂O loading and the nature of the target pollutant influence the photocatalytic efficiency. This study has also highlighted the role of chlorinated radicals in the degradation process, especially for chloroform. The degradation process of chloroform generated chlorine radicals, which not only contributed to the degradation of other VOCs, but also enhanced the overall oxidative capacity of the system. This synergistic effect was observed to accelerate pollutant removal and improve the antibacterial efficacy against E. coli. The Cu₂O-NPs/TiO₂-NTs composites demonstrated significant reusability and antibacterial properties, highlighting their potential for sustainable indoor air purification applications. Full article

In this study, silver nanoparticles (Ag NPs) were synthesized on the surface of rutile-phase titanium dioxide (R-TiO₂) using a plasma-assisted technique. Comprehensive analyses were conducted to investigate the structural, morphological, optical, and electrical properties of the synthesized nanocomposites. Transmission electron microscopy (TEM) images revealed the uniform decoration of Ag NPs (average size: 29.8 nm) on the R-TiO₂ surface. X-ray diffraction (XRD) confirmed the polycrystalline nature of the samples, with decreased diffraction peak intensity indicating reduced crystallinity due to Ag decoration. The Williamson–Hall analysis showed increased crystallite size and reduced tensile strain, suggesting grain growth and stress relief. Raman spectroscopy revealed quenching and broadening of R-TiO₂ vibrational modes, likely due to increased oxygen vacancies. X-ray photoelectron spectroscopy (XPS) confirmed successful plasma-assisted deposition and the coexistence of Ag⁰ and Ag⁺ states, enhancing surface reactivity. UV-Vis spectroscopy demonstrated enhanced light absorption across the spectral range, attributed to localized surface plasmon resonance (LSPR), and a reduced optical bandgap. Dielectric properties, including dielectric constants, loss factor, and AC conductivity, were evaluated across frequencies (4–8 MHz) and temperatures (20–240 °C). The AC conductivity results indicated correlated barrier hopping (CBH) and overlapping large polaron tunneling (OLPT) as the primary conduction mechanisms. Composition-dependent dielectric behavior was interpreted through the Coulomb blockade effect. These findings suggest the potential of plasma assisted Ag NP-decorated R-TiO₂ nanostructures for photocatalysis, sensor and specific electro electrochemical systems applications. Full article

Titanium dioxide (TiO₂) nanoparticles (NPs) are widely used in various industries and are increasingly found in environmental systems, especially in soil. However, the environmental behavior of TiO₂ NPs is still poorly understood. Hence, this study aims to fill this gap by investigating the short- and long-term effects of soil solutions on anatase and rutile NPs. The experiments were carried out using two soil types, which have very different chemical properties, in order to obtain a more nuanced picture of how these factors affect the stability, surface chemistry, and photocatalytic activity of TiO₂ NPs. The results indicate that acidic soil solutions with lower ionic strength tend to enhance the stability of TiO₂ NPs by preventing aggregation, while alkaline solutions with higher ionic strength promote aggregation and reduce photocatalytic activity by blocking active sites. Additionally, the adsorption of organic matter and other soil components on the nanoparticle surface further complicates their behavior, potentially reducing their photocatalytic efficiency. The interaction time plays a crucial role in determining the long-term fate of TiO₂ NPs in soil environments. Extended exposure to soil solutions leads to changes in crystallite size, surface charge, and the adsorption of functional groups, which, in turn, affect the NPs’ photocatalytic properties. Full article

Objectives: Bacterial infections, mainly due to rising antimicrobial resistance (AMR), are an immense global health threat, complicating treatment, prolonging illness, and increasing mortality. The WHO lists AMR as one of the major threats to human health. Biofilm plays a crucial role in AMR, protecting bacteria and promoting resistance. Targeting biofilms improves antibiotic efficacy and reduces chronic infections. Titanium dioxide nanoparticles (TiO₂-NPs) have emerged as a promising candidate in drug delivery, diagnostics, and antimicrobial therapies due to their distinctive properties. Methods: Due to the challenge of AMR and the potential of green-synthesized nanoparticles, this study investigates antibiofilm activity and intracellular ROS production by TiO₂-NPs produced from Linum usitatissimum seed extract. Results: The crystal size of LU-TiO₂-NPs was determined as 8.024 nm, and TEM validated the average particle size as 14.30 ± 5.93 nm. FTIR confirmed the presence of the O-Ti-O bond near 684 cm⁻¹. LU-TiO₂-NPs effectively inhibited biofilms, reducing biofilms of Staphylococcus aureus MTCC 3160 and Escherichia coli ATCC 25922 by 79.96% and 71.85%, respectively. Microscopic analysis also showed a reduction in bacterial adherence and colonization. This inhibition was supported by the reduction in exopolysaccharides, a major biofilm component. The biofilm inhibition was likely mediated by the induction of intracellular ROS production by LU-TiO₂-NPs. Furthermore, LU-TiO₂-NPs successfully eradicated established biofilms of both the Gram +ve and Gram −ve bacteria. Conclusion: The findings demonstrate that TiO₂-NPs hold significant promise in tackling biofilm-associated bacterial infections and may prove beneficial in addressing the escalating problem of AMR. Full article

The enhancement of tribological properties represents a pivotal strategy for achieving energy efficiency and environmental protection. Titanium dioxide (TiO₂) nanomaterials have been garnering significant attention due to their exemplary tribological properties and due to the abundance of titanium reserves. The present review is concerned with the study of TiO₂ nanomaterials in lubricants. The properties and various synthesis methods of TiO₂ nanomaterials are presented. The dispersion stability of these TiO₂ nanomaterials in lubricating oils is discussed in depth, as well as strategies to improve their dispersion stability, such as enhancing compatibility with base oils, reducing the dynamic light scattering (DLS) particle size, modulating the zeta potential, and optimizing the drying step. Aggregation and dispersion instability remain key challenges for TiO₂ nanomaterials, especially bare TiO₂ nanoparticles (NPs). In contrast, in situ surface-modified TiO₂ NPs show improved stability and tribological performance, offering promise for further research. The tribological performance of lubricants has been demonstrated to be enhanced by TiO₂ nanomaterials, with the observed enhancement attributed to the synergistic effect of multiple mechanisms, including rolling, patching, polishing, and the formation of a protective film. Furthermore, future research suggestions are proposed to provide a reference for the design and synthesis of high-performance TiO₂ nano-lubricants and promote their wide application. Full article

Antimicrobial polymeric coatings rely not only on their surface functionalities but also on nanoparticles (NPs). Antimicrobial coatings gain their properties from the addition of NPs into a polymeric matrix. NPs that have been used include metal-based NPs, metal oxide NPs, carbon-based nanomaterials, and organic NPs. Copper NPs and silver NPs exhibit antibacterial and antifungal properties. So, when present in coatings, they will release metal ions with the combined effect of having bacteriostatic/bactericidal properties, preventing the growth of pathogens on surfaces covered by these nano-enhanced films. In addition, metal oxide NPs such as titanium dioxide NPs (TiO₂ NPs) and zinc oxide NPs (ZnONPs) are used as NPs in antimicrobial polymeric coatings. Under UV irradiation, these NPs show photocatalytic properties that lead to the production of reactive oxygen species (ROS) when exposed to UV radiation. After various forms of nano-carbon materials were successfully developed over the past decade, they and their derivatives from graphite/nanotubes, and composite sheets have been receiving more attention because they share an extremely large surface area, excellent mechanical strength, etc. These NPs not only show the ability to cause oxidative stress but also have the ability to release antimicrobial chemicals under control, resulting in long-lasting antibacterial action. The effectiveness and life spans of the antifouling performance of a variety of polymeric materials have been improved by adding nano-sized particles to those coatings. Full article