Retraction notice to “Oil-in-water emulsions containing titanium dioxide nanoparticles: A tribological study on forged steel-steel surfaces” [Colloids Surf. A: Physicochem. Eng. Asp. 719 (2025) 136994

Abstract The Ag-doped TiO2 and TiO2-Pt nanoparticles have been synthesized using a simple, eco-friendly method by fine grinding with zero solutions used. TiO2 has been loaded with just 5 wt.% of Ag and Pt in TiO2-Ag and TiO2-Pt, respectively. The prepared samples have been characterized using various techniques. TEM showed good dispersion and distribution of Ag and Pt within the TiO2 host matrix using this simple method with fine grinding. Furthermore, EDX analysis was conducted reveal the difference in compositions of the TiO2-Ag and TiO2-Pt NPs samples is illustrated. From the elemental mapping mode, highly uniformly dispersed Ag and Pt nanoparticles on the TiO2. The XRD patterns of the synthesised TiO2-Ag and TiO2-Pt are shown in the planes of the anatase phase and the lattice constant of anatase. The lattice constant was not influenced by the doped Ag and Pt. The thermal behaviour was studied by DSC-TGA analysis.The weight loss at 900⁰C in the TGA curve is 13% and 12%, respectively, with around 5% thermal enhancement when only 5 wt.% of Ag and Pt are added. That is a promising potential application of TiO2 in solar cells with high thermal stability

Salinity stress severely limits rice productivity and grain quality worldwide. Although exogenous foliar application of titanium dioxide nanoparticles (nano-TiO2) has been reported to enhance crop stress tolerance, its regulatory roles in yield formation and grain quality in rice varieties with differing salt tolerance are not well understood. In the present study, two contrasting rice varieties, viz., Jingliangyou 3261 (JLY3261; salt-tolerant) and Yuxiangyouzhan (YXYZ; salt-sensitive), were applied with five nano-TiO2 foliar application treatments-viz., CK: water spray; Ti1: 15 mg L-1; Ti2: 30 mg L-1; Ti3: 45 mg L-1; and Ti4: 60 mg L-1-at the jointing and panicle initiation stages. Plants were irrigated with 0.3% saltwater to simulate salt stress. The results showed that Ti2 and Ti3 treatments led to 8.59% and 14.80% increases in grain yield in JLY3261 and YXYZ, respectively, compared with CK. Ti2 and Ti3 treatments significantly increased the leaf area index, net photosynthetic rate, and aboveground biomass of both varieties at the heading stage. Meanwhile, the activities of antioxidant enzymes such as superoxide dismutase and peroxidase, as well as nitrogen metabolism enzymes including nitrate reductase and glutamine synthetase, were improved with a substantial reduction in malondialdehyde contents. Application of nano-TiO2 upregulated the expression of ion transport-related genes such as OsSOSs, OsNHXs and OsHKTs, thus improving leaf K+ accumulation and reducing Na+ content to optimize the K+/Na+ ratio. In addition, Ti2 and Ti3 treatments improved the milled rice rate, head rice rate, and protein content, while they decreased the chalkiness degree of both rice cultivars. Principal component analysis showed that the aboveground biomass at the heading stage was a core evaluation index for both varieties. Overall, foliar application of 30-45 mg L-1 nano-TiO2 was found to be effective regarding growth and yield improvement in rice under saline conditions. This study provides a theoretical basis for agro-management strategies for rice cultivation in saline-alkaline soils.

Abstract Kiwifruit is prone to rapid softening due to ethylene accumulation and is highly susceptible to microbial infection and decay. To address these two major challenges, a multifunctional film was developed via electrospinning using polyvinyl alcohol (PVA) and pullulan (PUL) as a composite polymer matrix, and incorporated with titanium dioxide (TiO2) nanoparticles and thymol (THY) as photocatalyst and natural antimicrobial agent, respectively. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed the uniform dispersion of TiO2 nanoparticles within the fibers without obvious aggregation. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) results verified the successful integration of anatase TiO2 and THY into the nanofiber film. The nanofiber film nearly completely degraded ethylene (200×10–6) within 4 h under irradiation, corresponding to a degradation rate of 12.5 µL/(g·h). Furthermore, the nanofiber film exhibited 100% antibacterial efficiency against Escherichia coli, Staphylococcus aureus, and Botryosphaeria. Compared with PUL/PVA film, the TiO2/THY/PUL/PVA composite film exhibited enhanced thermal stability, ultraviolet absorption capacity, and mechanical strength. Under 4 °C storage condition, the active packaging film extended the shelf life of kiwifruit to more than 35 d, effectively maintained fruit firmness and color, delayed the decline in total soluble solids, vitamin C, and anthocyanins, decelerated weight loss and malondialdehyde accumulation, and markedly suppressed microbial infection. This study provides an effective strategy for developing active packaging materials with ethylene degradation and antimicrobial functions, offering considerable potential for advancing postharvest preservation technologies for kiwifruit and other climacteric fruits.

Introduction: Glass Ionomer Cements (GICs), commonly used in restorative dentistry, demonstrate favorable biocompatibility and chemical bonding to tooth structures. However, their antibacterial properties are often inadequate, potentially leading to secondary caries due to biofilm formation on the material's surface. Incorporating Titanium Dioxide (TiO₂) nanoparticles into GICs has emerged as an effective strategy to enhance their antimicrobial properties. Methods: This study investigated the solubility and water sorption of a self-cured restorative dental GIC modified with TiO₂ nanoparticles at concentrations of 0%, 0.5%, 1%, and 3%. The antimicrobial and antibiofilm effects of the TiO₂-modified GIC were then evaluated against Streptococcus mutans (S. mutans) using a series of in vitro assays, including disk diffusion, Minimum Inhibitory Concentration (MIC), and Minimum Biofilm Inhibitory Concentration (MBIC). Results: A statistically significant difference was observed in the inhibition zones among the groups (P = 0.001), with the 3% TiO₂ group showing significantly greater antimicrobial activity compared to the 1% (P = 0.02) and 0.5% (P = 0.001) groups. TiO₂ addition also significantly enhanced resistance to biofilm formation (P = 0.0001), with the 3% group again demonstrating superior results over 1% (P = 0.0001) and 0.5% (P = 0.0001). Regarding solubility, there was a significant difference between groups (P = 0.001), and the 3% group exhibited the lowest solubility (P = 0.0001). No statistically significant difference was found in water sorption among the groups (P = 0.1). Conclusion: This novel approach shows promise for reducing the risk of secondary caries in clinical applications.

Endocrine-disrupting effects of titanium dioxide nanoparticles on the female reproductive system: Evidence from an ovariectomized rat model.

Combined effects of nanomaterials and climate change on aquatic ecosystems: Toxicity, interactions, and regulatory challenges.

Sunscreen-derived nano-TiO2 undermines viability and recruitment of the Mediterranean foundation alga Ericaria amentacea.

Retraction notice to "Antibacterial, antifungal, antidiabetic, and antioxidant activities potential of Coleus aromaticus synthesized titanium dioxide nanoparticles" [Environ. Res. 216 (2023) 114714

Multifunctional titanium dioxide nanoparticles synthesized from Ephedra sinica: antimicrobial, anticancer, photocatalytic, and larvicidal activities

Effect of flow regimes on flowability of titania nanoparticle agglomerates and particle size distribution in a conical fluidized bed: evaluation of particle collision parameters and collision models

Geometry effect on titania nanoparticle distribution and its impact on the photocatalytic properties of vat photopolymerization 3D-printed acrylic resin-based nanocomposites

Molecular dynamics simulation of the adsorption and coating stability of succinic acid on the surface of titanium nanoparticles

Titanium dioxide (TiO2) nanoparticles were green-synthesized using whole Gracilaria edulis. The G. edulis was washed, dried, powdered and extracted, which is rich with various natural reducing, stabilizing, and capping agents. The TiO2 nanoparticles confirmed with strong UV-Vis absorption with peaks between 250 and 350nm, consistent with the anatase TiO2 band gap. FTIR analysis revealed surface hydroxyl groups and organic residues from the algal extract, potentially facilitating reactive oxygen species (ROS) generation. XRD confirmed a highly crystalline nature of green-synthesized TiO2 nanoparticles and showed irregular nanoscale morphology by SEM, while EDS confirmed Ti and O with minor algal-derived elements. TEM images showed mostly spherical, well-dispersed nanoparticles with minimal aggregation. Antimicrobial evaluation demonstrated stronger inhibition, with MIC values of 0.50mg/mL for bacteria and 0.25mg/mL for fungi. Photocatalytic degradation of methylene blue under sunlight achieved efficiencies of 90.1-94.4% at neutral pH (7) and 88.3-90.1% at alkaline pH (9), with performance improving at higher TiO2 loadings (10-30ppm), while acidic pH showed slightly lower but variable degradation. Immobilization within sodium alginate produced uniform, stable beads with minimal leaching, suitable for reuse, and biofilm assays demonstrated concentration-dependent inhibition of bacterial biofilm formation. These results highlight that G. edulis-mediated TiO2 nanoparticles are promising sustainable materials in wastewater treatment and antimicrobial work because they have good physiochemical properties, strong antimicrobial and anti-biofilm action, and high dye degradation by photocatalysts.

Microbial assisted biogenic synthesis of titanium dioxide nanoparticles for enhanced methylene blue removal from aqueous solutions

Glass fiber reinforced polymers (GFRPs) have drawn significant attention given their lightweight, mechanical resistance and tunable properties through constituent selection. Due to environmental concerns, research efforts have focused on incorporating sustainable materials, such as bio-epoxy resins, to reduce the ecological impact of GFRPs. This study characterizes a GFRP containing a bio-epoxy resin matrix, various loadings of titanium dioxide (TiO2) nanoparticles, and a stabilized arrangement of glass fiber. The unreinforced composite exhibited a tensile strength and modulus of 214 MPa, and 13 GPa, respectively, and a flexural strength and modulus of 375 MPa and 14.5 GPa, respectively. The addition of TiO2 produced an improvement in mechanical response for all the composites. The formulation with 1 wt.% TiO2 showed the best tensile response with an improvement of 13% and 14% for its tensile strength, and modulus, respectively; meanwhile, the composites with 2 wt.% TiO2 attained an improvement of 19% and 40% for the flexural strength and modulus, respectively. Scanning electron microscopy (SEM) revealed significant changes in the fracture mechanism of the composites, while energy-dispersive spectroscopy (EDS) confirmed an even nanoparticle distribution. Additionally, machine learning (ML) models were developed to predict the mechanical response as a function of the TiO2 content.

This study presents a sustainable approach to managing maize anthracnose stalk rot caused by Colletotrichum graminicola using alginate beads loaded with titanium nanoparticles (TiNPs) and chitosan nanoparticles (ChNPs). Encapsulation altered nanoparticle properties, as confirmed by UV-vis absorption at 210-270 nm, and Fourier transform infrared spectroscopy (FTIR) cross-linking signals. ζ-Potential and particle size distribution measurements indicated aggregation tendency of TiNPs, uniform dispersion of ChNPs, and heterogeneous surface charge-size in composite beads. Nanoparticle beads were spherical (4.5-5.2 nm), while composite were ellipsoidal (4.76 nm). ChNPs beads exhibited superior hydration, mass stability, and 81% antifungal activity, whereas composite beads showed 64% inhibition. Complete disease control was achieved in maize plants treated with beads of either ChNPs or TiNPs + ChNPs, accompanied by significant improvement in the plant performance attributes, both outperforming chemical fungicides. This research highlights nanoparticle-based alginate beads as a scalable, eco-friendly biofungicidal solution for agriculture.

Abstract This work investigates the mechanical characteristics of epoxy nanocomposites reinforced with titanium dioxide (TiO 2 ) and silicon oxide (SiO 2 ) nanoparticles. The intrinsic brittleness and low impact resistance of neat epoxy resin limit its use in high-performance settings, despite its benefits, which include high stiffness, chemical stability, and thermal resistance. The inclusion of nano-sized reinforcements was investigated as a solution to these constraints, with the objective of improving the impact, tensile, flexural, and compressive qualities of epoxy-based composites. The presence of nanoparticles significantly improved all tested properties, according to mechanical characterization. The tensile strength of the nanocomposites increased from 67 MPa for pure epoxy to 84 MPa for the composite that contained 2 wt.% TiO 2 and 1 wt.% SiO 2 . The flexural strength of the nanocomposites increased by 242.5% (from 73 MPa for pure epoxy to 250 MPa for the composite). The compressive strength and strain tolerance of all nanocomposite samples have significantly improved, and stress increases nearly monotonically with strain. This enhancement is ascribed to improved interfacial bonding between the nanoparticles and matrix, which promoted energy dissipation during fracture. Improved interfacial bonding and particle dispersion in low to moderately filled systems were confirmed by morphological analysis using SEM and EDX, which also showed uniform distribution and little void formation. These improved epoxy nanocomposites are especially well-suited for structural uses in the automotive, marine, and aerospace industries where durability and high strength-to-weight ratios are crucial. They are also perfect for protective coatings and electronic encapsulants in harsh environments due to their enhanced impact resistance and surface hardness.

Titanium dioxide nanoparticles (TiO2 NPs) are used in agriculture, cosmetics, energy, and environmental applications, necessitating advanced methods to evaluate their effects on biological systems such as plant growth. This study demonstrates the use of biospeckle optical coherence tomography (bOCT), a novel and non-invasive technique, to rapidly assess the size and concentration-dependent impacts of TiO2 NPs as well as the synergistic effects of TiO2 NPs and polyethylene microplastics (PEMPs) on lentil (Lens culinaris) seeds. The primary objective was to validate bOCT as a rapid and non-invasive tool for assessing NPs-induced biological responses in plants. Seeds were treated with TiO2 particles (<5 µm,<100 nm, 21 nm) at concentrations of 0, 25, 100, and 200 mg/L. The sizes were selected based on commercially available TiO2 NPs grades in industrial and agricultural applications. For synergy experiments, TiO2 NPs (21 nm) at 25 and 100 mg/L were combined with PEMPs (744–4990 nm) at concentration-based ratios of 1:1 and 1:2. A swept-source OCT system (central wavelength: 1.3 µm; bandwidth: 125 nm; sweep frequency: 20 kHz), acquired OCT structural images at 12.5 frames per second and biospeckle images were calculated as the ratio of the standard deviation to the mean of 100 OCT structural images over an 8-second interval, at 0, 5, 10, and 20 hours (h) post-exposure. Smaller TiO2 NPs (<100 nm) enhanced internal activity at lower concentrations (25 mg/L), while larger particles (<5 µm) exhibited similar effects at higher concentrations (200 mg/L). These observations were qualitatively consistent with conventional physiological measurements, including germination rates, growth parameters, and antioxidative enzyme activities recorded over 7 days. The co-application of TiO2 NPs and PEMPs at a 1:1 ratio alleviated the reduction in internal activity caused by PEMPs alone, while the 1:2 ratio led to a significant decrease in biospeckle contrast, indicating suppressed internal seed activity. bOCT successfully detected early biological responses of TiO2 NPs within 20 h, demonstrating its efficiency compared to the conventional methods. The ability of bOCT to monitor dynamic internal changes highlights its potential as a rapid tool for assessing NPs as well as their synergistic effects with polyethylene microplastics on plants.

The importance of nanotechnology in protecting the environment is represented in multiple applications, including, for example, the green synthesis of nanoparticles (NPs), using the remains of plant parts, as well as photolysis application that used semiconductors NPs which showed a clear effect in treating water from organic pollutants, this study combines these two applications, in terms of green synthesis of titanium dioxide nanoparticles (TiO2NPs) using melon peel (Cucumis melo L.) in sol-gel method, as well as, the photodegradation of methylene blue dye (MB) by using a new irradiation photoreactor device which has designed and implemented for this purpose. This device used to irradiate MB dye with three different types of ultraviolet$-$visible (UV) light sources to study the photodegradation with different cases, first on circulation of MB dye only, second when irradiation MB dye with UV-A, UV-B, UV-C light sources with circulation, finally, the effect of adding (0.05 g) of green synthesized of TiO2NPs by using melon peel extract in sol-gel method with irradiation and circulation MB dye in the system. Different percentage of MB dye removal where reported. The prepared of TiO2NPs catalysts were characterized using, Energy dispersive analysis (EDX), Ultraviolet$-$visible spectroscopy (UV-Vis), Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray spectroscopy (XRD), Atomic force microscopy (AFM). High performance of photodegradation was absorbed under UV-C, UV-B irradiation of MB dye in 90 min.