Incorporation of Zirconium Oxide Nanoparticles in Adhesive Resin for Bonding of Brackets to Enamel Conditioned with Er,Cr:YSGG, Photodynamic Therapy, and Phosphoric Acid.

Objective: To evaluate the effect of enamel conditioning methods, that is, total-etch and rinse (TER), Er,Cr:YSGG (ECYL), and photodynamic therapy (PDT) on the shear bond strength (SBS) of orthodontic metallic brackets bonded using Zirconium oxide experimental adhesive (ZOEA). Methods: Sixty human incisor buccal surfaces were cleaned and allocated into three groups based on the method of enamel surface treatment, that is, TER using 37% phosphoric acid gel, methylene blue photosensitizer activated by PDT and ECYL (n = 20 each). Each group was further divided into two subgroups (n = 10) based on the type of adhesive, that is, ZOEA and experimental adhesive (EA). Metallic brackets were seated using composite resin. Samples were placed in a universal testing machine for SBS and failure mode using the ARI index. One-way analysis of variance and post hoc Tukey were used for multiple comparisons. ARI was presented in percentages in different investigated groups. Results: TER+ZOEA (17.16 ± 0.41 MPa) displayed the highest bond integrity. However, group PDT+EA (11.34 ± 0.25 MPa) demonstrated the lowest bond scores. The intergroup comparison revealed that the TER system displayed significantly higher SBS values than the PDT and ECYL groups (p < 0.05). The intragroup comparison revealed that enamel conditioned with TER and brackets bonded with ZOEA and EA displayed comparable bond integrity (p > 0.05). Conclusions: Enamel conditioned with TER bonded to a metallic bracket displayed better bond strength than PDT and ECYL. Zirconium oxide nanoparticles incorporated in adhesive have proved to be promising in improving the bond integrity of adhesive.

Effect of zirconium oxide nano-coating on frictional resistance of orthodontic wires.

Objectives: Minimizing the frictional force between orthodontic wire and brackets is imperative to safely obtain a more favorable result by applying lower loads. Several methods have been proposed for this purpose such as changing the wire shape/size, changing the bracket design, and coating wires with different materials. This study aimed to assess the effect of zirconium oxide (ZrO2) nano-coating on frictional resistance of three types of orthodontic wires. Materials and Methods: This in vitro, experimental study evaluated 42 pieces of nickel-titanium (NiTi), stainless steel (SS), and beta-titanium (TMA) orthodontic wires, and 42 maxillary canine brackets. The samples were divided into six groups with and without ZrO2 nano-coating. The nano-coating was applied on the wires using the sol-gel technique. The presence of ZrO2 nano-coating was evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The surface roughness of the samples was evaluated using atomic force microscopy (AFM). The brackets and wire had a 5° angle relative to each other. The static and kinetic friction of the samples were evaluated in the presence of artificial saliva and occlusogingival movements in a universal testing machine. Data were analyzed by the Shapiro-Wilk's test, one-way ANOVA, Kruskal-Walli's test, Mann-Whitney U test, independent t-test, and Tukey's test. Results: ZrO2 nano-coating was only observed on TMA wires. The surface roughness of coated NiTi and SS wires had no significant difference from that of non-coated wires (P > 0.05). However, this difference was significant for TMA wires with and without the coating (P < 0.05). The static and kinetic friction were not significantly different between wires with and without coating (P > 0.05). Conclusions: ZrO2 nano-coating could only be applied on TMA wires, and had no significant efficacy for reduction of static or kinetic friction of TMA wires.

Fabrication of different adsorbents based on zirconium oxide, graphene oxide, and dextrin for removal of green malachite dye from aqueous solutions.

In this study, graphene oxide and amine graphene were studied by binding to dextrin and zirconium oxide nanoparticles as adsorbent nanocomposites to the removal of dye. Identification and characterization of the synthesized materials were examined using FTIR, XRD, SEM, and BET analyses. Adsorption tests between adsorbents and green malachite (MG) dye solution for the synthesized nanocomposites were performed by considering parameters such as contact time, solution pH, and adsorbent dosage. The data indicated that dye removal increased with increasing the amount of adsorbent dosage. Increased dye removal by increasing the adsorbent dosage can be attributed to the increase of availability of the number of active sites. The active adsorption sites are saturated during the adsorption process, by the molecules of the adsorbate and filled over time. The results showed that the synthesized bio-composite had malachite green removal ability from aqueous media.

Photocatalytic degradation of methylene blue dye using newly synthesized zirconia nanoparticles.

Zirconium oxide nanoparticles (ZrO2NPs) were prepared using the leaf extract of Muntingia calabura as a reductant. The absorption peak at 232 nm confirmed the signature peak for ZrO2NPs with band energy at 5.07 eV. The ZrO2NPs were tetragonal and highly crystalline, possessing a mean diameter of 14.83 nm as confirmed by XRD studies. The lattice constants (a = 0.362 nm and c = 0.511 nm) were consistent with the literature. Spherical nanoaggregates (29.25 nm) were seen in FESEM image and the specific signals for Zr and O were noticed in EDS image. The tetragonal phase of the ZrO2NPs were further confirmed from the XPS and Raman studies. PL spectrum had a sharp emission at 493 nm. The FTIR spectrum revealed the presence of various functional groups. ZrO2NPs were thermally stable with 5.76% total weight loss - as revealed from TGA profile. The photocatalytic breakdown of methylene blue (MB) dye under the influence of solar irradiation was performed using ZrO2NPs which exhibited 89.11% degradation within 5 h. Hence, the synthesized ZrO2NPs can be used as an alternate potential photocatalyst for the degradation of various dyes present in waste streams.

Reversible Martensitic Phase Transition in Yttrium-Stabilized ZrO2 Nanopowders by Adsorption of Water.

The present study was aimed at revealing the influence of the mechanical stress induced by water molecule adsorption on the composition of crystalline phases in the ZrO2 + 3 mol% Y2O3-nanoparticles. Three basic methods were used to determine the phase transition: neutron diffraction, Raman microspectroscopic scanning, and X-ray diffraction. The fact of reversible phase-structural ß â†’ α transformation and the simultaneous presence of two polymorphic structural modifications (ß is the phase of the tetragonal syngony and α of monoclinic syngony in nanosized particles (9 nm)) under normal physical conditions was established by these methods. An assumption was made regarding the connection of the physical mechanism of transformation of the extremely nonequilibrium surface of nanoparticles with electronic exchange of the material of the near-surface layer of nanoparticles with the adsorption layer through donor-acceptor interaction. The principal possibility of creating direct-acting hydroelectric converters based on nanoscale YSZ (Yttria-Stabilized Zirconia) systems due to the reversible character of the considered effect was shown.

Ammonia removal from industrial effluent using zirconium oxide and graphene-oxide nanocomposites.

The present study developed and evaluated nano-adsorbents based on zirconium oxide and graphene oxide (ZrO2/GO) as a novel adsorbent for the efficient removal of ammonia from industrial effluents. Fourier transform infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray Spectroscopy, and X-ray diffraction were used to evaluate and identify the novel adsorbent in terms of morphology, crystallography, and chemical composition. The pH (7), adsorbent quantities (20 mg), adsorbent contact time (30 min) with the sample, and initial ammonia concentration were all tuned for ammonia uptake. To validate ammonia adsorption on the ZrO2/GO adsorbent, several kinetic models and adsorption isotherms were also utilized. The results showed that the kinetics of ammonia adsorption are of the pseudo-second order due to high R2 (>0.99) value as compared first-order (R2 = 0.52). The chemical behavior and equilibrium isotherm were analyzed using the isotherm models and Langmuir model provided high R2 (>0.98) as compared Freundlich (>0.96). Hence, yielding a maximum uniform equilibrium adsorption capacity of 84.47 mg g-1. The presence of functional groups on the surface of graphene oxide and ZrO2 nanoparticles, which interact efficiently with ammonia species and provide an efficient surface for good ammonia removal, is most likely to be responsible.

Efficacy of zirconium oxide nanoparticles coated on stainless steel and nickel titanium wires in orthodontic treatment.

It is of particular intrigue to synthesize, analyze anti-bacterial, anti-inflammatory activity, cytotoxicity effect of clove and cardamom reinforced zirconium oxide nanoparticles to coat the orthodontic archwires and study its ramifications. Characterization of nanoparticles was done using Transmission electron microscopic analysis (TEM). Antimicrobial activity was assessed using agar well diffusion method. Cytotoxic effect was assessed using Brine Shrimp Assay. Anti-inflammatory activity was completed using Bovine Serum Albumin (BSA). A Digital magnetic stirrer with a hot plate was used to coat orthodontic arch wires such as NiTi and SS. TEM spherical shape was of size 5 -20 nm. Minimal cytotoxicity was observed at 50 µL. Anti-inflammatory property was fair. Antimicrobial activity against Lactobacillus species, streptococcus mutans staphylococcus aureus and Candida albicans was recorded. NiTi and SS showed a colour shift from silver to orange red with a uniform surface coating on wires. Thus, green synthesized zirconium oxide nanoparticles have potent antimicrobial, anti-inflammatory properties with minimal cytotoxicity for further consideration as nano-coatings on orthodontic archwires such as NiTi and Stainless Steel.

Interaction between Amorphous Zirconia Nanoparticles and Graphite: Electrochemical Applications for Gallic Acid Sensing Using Carbon Paste Electrodes in Wine.

Amorphous zirconium oxide nanoparticles (ZrO2) have been used for the first time, to modify carbon paste electrode (CPE) and used as a sensor for the electrochemical determination of gallic acid (GA). The voltammetric results of the ZrO2 nanoparticles-modified CPE showed efficient electrochemical oxidation of gallic acid, with a significantly enhanced peak current from 261 µA ± 3 to about 451 µA ± 1. The modified surface of the electrode and the synthesised zirconia nanoparticles were characterised by scanning electrode microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDXA), X-ray powdered diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Meanwhile, the electrochemical behaviour of GA on the surface of the modified electrode was studied using differential pulse voltammetry (DPV), showing a sensitivity of the electrode for GA determination, within a concentration range of 1 × 10-6 mol L-1 to 1 × 10-3 mol L-1 with a correlation coefficient of R2 of 0.9945 and a limit of detection of 1.24 × 10-7 mol L-1 (S/N = 3). The proposed ZrO2 nanoparticles modified CPE was successfully used for the determination of GA in red and white wine, with concentrations of 0.103 mmol L-1 and 0.049 mmol L-1 respectively.

In vitro induction of odontogenic activity of human dental pulp stem cells by white Portland cement enriched with zirconium oxide and zinc oxide components.

Background . The aim of this in vitro study was to investigate the effect of zinc oxide (ZnO) and zirconium oxide (ZrO2) microparticles (MPs) and nanoparticles (NPs) in combination with white Portland cement (WPC) on odontogenic capacity of human dental pulp stem cells over a period of 21 days. Methods . Synthesized ZnO and ZrO2 particles were characterized using scanning electron microscopy and transmission electron microscopy. The viability of human dental pulp stem cells was measured by a 3-(4,5-dimethylthiazolyl-2-yl)-2,5- diphenyltetrazolium bromide assay at 7-, 14- and 21-day intervals after seeding on WPC disks enriched with ZnO and ZrO2 MPs and NPs. Odontogenic potential of ZnO and ZrO2 particles in combination with WPC was investigated by alkaline phosphatase (ALP) activity and ionized calcium level of supernatant culture media at different time intervals. Data were analyzed using one-way ANOVA and post hoc Tukey tests. Results . All the materials exhibited cell viability over a 21-day period, except for WPC with ZnO NPs on day 7, although it was not statistically significant (P>0.05). The ALP activity and ionized calcium level increased in all the groups compared to the control group (P<0.05). ZnO NPs had superior effect on odontogenic activity and calcium ion release compared to ZnO MPs (P=0.046). There was no significant difference between ZrO2 MPs and NPs in odontogenic activity (P>0.05). Conclusion . WPC enriched with ZnO and ZrO2 increased ALP activity and calcium ion release of human dental pulp stem cells over a period of 21 days in vitro.

Effect of Trigonella foenum Extract and ZiO2 Nanoparticles on Some Pathogenic Fungi and Bacteria

Aim: The current venture, were made to evaluate the inhibitory effect of Trigonella foenum seed Extract and ZiO2 Nanoparticles on some selected species of Fungi and Bacteria. Materials and Methods: two bacterial species included Pseudomonas aeruginosa and Staphylococcus aureus and three fungal species which is Cryptococcus neoformans, Candidda albicans and Chaetomium were used to evaluate the antibacterial activity of Trigonella foenum Extract and ZiO2 Nanoparticles. Results: This study showed that the Zirconium Oxide (ZiO2) nanoparticles have antifungal and antibacterial activities on the isolates of Cryptococcus neoformans, Candida alicans and Staphylococcus aureus, respectively. While the antimicrobial activity of Zirconium Oxide nanoparticles on the Chaetomium and Pseudomonas aeruginosa was negative. All tested fungi and bacterial isolates were found to be sensitive to Trigonella foenum seed extract, the results of the compination of the ZiO2 Nanoparticle and the Trigonella foenum seed extract were poisitive for all tested fungi isolates and bacterial isolates. The XRD analysis was done for Zirconium Oxide nanoparticles and the result showed that the biocrystallization on the surface of the Zirconium Oxide manoparticles. The average partides size was about (29.8) nm. Conclusions: This investigation conclude that the use of Trigonella foenum seed Extract has the effect of killing all bacteria and fungi under study, result indicate the Trigonella foenun seed Extract best antibacterial efficacy than the ZiO2 together (AU)

Thermal control of the defunctionalization of supported Au25(glutathione)18 catalysts for benzyl alcohol oxidation.

Au25(SG)18 (SG - glutathione) clusters deposited on ZrO2 nanoparticles have been used as a catalyst for benzyl alcohol oxidation. Calcination was performed at different temperatures to study the ligand and particle size effect on the catalytic activity. In contrast to most gold nanoclusters which have to be completely defunctionalized for maximum catalytic activity, the partially defunctionalized Au25(SG)18@ZrO2 catalyst, thermally treated at 300 °C, exhibits full conversion of benzyl alcohol within 15 h under atmospheric pressure with 94% selectivity towards benzaldehyde.

The effects of adding various ratios of zirconium oxide nanoparticles to poly(methyl methacrylate) on physical and mechanical properties.

The aim of the present study is to evaluate the transverse strength, modulus of elasticity, surface roughness, hardness, and water sorption/solubility of nanoparticle zirconium oxide (nano-ZrO2) added to heat-cured poly(methyl methacrylate) (PMMA) after thermocycling. The specimens were divided into four groups according to the ratio of nano-ZrO2 addition to heat-cured PMMA; group 1: 5% nano-ZrO2; group 2: 10% nano-ZrO2; group 3: 20% nano-ZrO2, and group 4 (control): PMMA without nano-ZrO2. A statistically significant decrease in transverse strength was observed by all additional rates of nano-ZrO2 compared with group 4 (control; P < 0.025). When hardness results were evaluated, groups 1 and 2 showed statistically higher values compared with groups 3 and 4 (P < 0.025). The surface roughness of group 3 was statistically higher than the other groups (P < 0.025), but it was within the clinically acceptable limits. As the nano-ZrO2 addition rate increased, water sorption/solubility values of the specimens also increased. Although nano-ZrO2 addition had an adverse effect on some mechanical and physical properties of heat-cured PMMA, it increased hardness values, implying that the addition of nano-ZrO2 would contribute positively to some mechanical properties of PMMA denture base material when nano-ZrO2 was homogeneously distributed in PMMA.

Surface Modifier-Free Organic-Inorganic Hybridization To Produce Optically Transparent and Highly Refractive Bulk Materials Composed of Epoxy Resins and ZrO2 Nanoparticles.

Surface modifier-free hybridization of ZrO2 nanoparticles (NPs) with epoxy-based polymers is demonstrated for the first time to afford highly transparent and refractive bulk materials. This is achieved by a unique and versatile hybridization via the one-pot direct phase transfer of ZrO2 NPs from water to epoxy monomers without any aggregation followed by curing with anhydride. Three types of representative epoxy monomers, bisphenol A diglycidyl ether (BADGE), 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (CEL), and 1,3,5-tris(3-(oxiran-2-yl)propyl)-1,3,5-triazinane-2,4,6-trione (TEPIC), are used to produce transparent viscous dispersions. The resulting ZrO2 NPs are thoroughly characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and solid-state 13C CP/MAS NMR measurements. The results from DLS and TEM analyses indicate nanodispersion of ZrO2 into epoxy monomers as a continuous medium. A surface modification mechanism and the binding fashion during phase transfer are proposed based on the FT-IR and solid-state 13C CP/MAS NMR measurements. Epoxy-based hybrid materials with high transparency and refractive index are successfully fabricated by heat curing or polymerizing a mixture of monomers containing epoxy-functionalized ZrO2 NPs and methylhexahydrophthalic anhydride in the presence of a phosphoric catalyst. The TEM and small-angle X-ray scattering measurements of the hybrids show a nanodispersion of ZrO2 in the epoxy networks. The refractive index at 594 nm ( n594) increases up to 1.765 for BADGE-based hybrids, 1.667 for CEL-based hybrids, and 1.693 for TEPIC-based hybrids. Their refractive indices and Abbe's numbers are quantitatively described by the Lorentz-Lorenz effective medium expansion theory. Their transmissivity is also reasonably explained using Fresnel refraction, Rayleigh scattering, and the Lambert-Beer theories. This surface modifier-free hybridization provides a versatile, fascinating, and promising method for synthesizing a variety of epoxy-based hybrid materials.

Effect of zirconium oxide nanoparticles addition on the optical and tensile properties of polymethyl methacrylate denture base material.

BACKGROUND: Polymethyl methacrylate (PMMA) is widely used for the fabrication of removable prostheses. Recently, zirconium oxide nanoparticles (nano-ZrO2) have been added to improve some properties of PMMA, but their effect on the optical properties and tensile strength are neglected. OBJECTIVE: The aim of this study was to investigate the effect of nano-ZrO2 addition on the translucency and tensile strength of the PMMA denture base material. MATERIALS AND METHODS: Eighty specimens (40 dumbbell-shaped and 40 discs) were prepared out of heat-polymerized acrylic resin and divided into four groups per test (n=10). The control group for each test included unreinforced acrylic, while the test groups were reinforced with 2.5, 5, and 7.5 wt% nano-ZrO2. Acrylic resin was mixed according to manufacturer's instructions, packed, and processed by conventional method. After polymerization, all specimens were finished, polished, and stored in distilled water at 37°C for 48±2 hours. Tensile strength (MPa) was evaluated using the universal testing machine while the specimens' translucency was examined using a spectrophotometer. Statistical analysis was carried out by SPSS using the paired sample t-test (p≤0.05). A scanning electron microscope was used to analyze the morphological changes and topography of the fractured surfaces. RESULTS: This study showed that the mean tensile strength of the PMMA in the test groups of 2.5%NZ, 5%NZ, and 7.5%NZ was significantly higher than the control group. The tensile strength increased significantly after nano-ZrO2 addition, and the maximum increase seen was in the 7.5%NZ group. The translucency values of the experimental groups were significantly lower than those of the control group. Within the reinforced groups, the 2.5%NZ group had significantly higher translucency values when compared to the 5%NZ and 7.5%NZ groups. CONCLUSION: The addition of nano-ZrO2 increased the tensile strength of the denture base acrylic. The increase was directly proportional to the nano-ZrO2 concentration. The translucency of the PMMA was reduced as the nano-ZrO2 increased. CLINICAL SIGNIFICANCE: Based on the results of the current study, the tensile strength was improved with different percentages of nano-ZrO2 additions. However, translucency was adversely affected. Therefore, it is important to determine the appropriate amount of reinforcing nano-ZrO2 that will create a balance between achieved properties - mechanical and optical.

Inhibitory effect of zirconium oxide nanoparticles on Candida albicans adhesion to repaired polymethyl methacrylate denture bases and interim removable prostheses: a new approach for denture stomatitis prevention.

BACKGROUND: Despite drawbacks, cold-cured acrylic resin is still the most common material used in denture repair. Zirconia nanoparticles were among the reinforcements added to increase the strength of the resin. The effect on Candida due to the addition of zirconia nanoparticles to the resin has not been investigated. PURPOSE: The aim of this study was to evaluate the effect of zirconia nanoparticles added to cold-cured acrylic resin on Candida albicans adhesion. MATERIALS AND METHODS: A total of 120 acrylic resin specimens with dimensions measuring 22×10×2.5 mm3 were prepared and divided into two equal groups. One group (repair) comprised heat-polymerized specimens that were sectioned at the center and prepared to create a 2 mm repair area that was repaired with cold-cured resin reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. The second group contained intact cold-cured acrylic resin specimens reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. Specimens were incubated at 37°C in artificial saliva containing C. albicans, and the effect of zirconia nanoparticles on C. albicans was assessed using two methods: 1) a slide count method and 2) a direct culture test. Variations in the number of living Candida were observed in relation to the different concentrations of zirconia nanoparticles. Analysis of variance (ANOVA) and post hoc Tukey's tests were performed for data analysis. If the P-value was ≤0.05, then the difference was considered as statistically significant. RESULTS: It was found that C. albicans adhesion to repaired specimens was significantly decreased by the addition of zirconia nanoparticles (P<0.00001) in comparison with the control group. Intact cold-cured groups and groups repaired with cold-cured resin reinforced with 7.5% wt zirconia nanoparticles showed the lowest Candida count. Tukey's test showed a significant difference between the repaired group and the intact cold-cured group, while the later demonstrated a lower Candida count. CONCLUSION: The addition of zirconia nanoparticles to cold-cured acrylic resin is an effective method for reducing Candida adhesion to repaired polymethyl methacrylate (PMMA) denture bases and cold-cured removable prosthesis. CLINICAL SIGNIFICANCE: Based on the results of the current study, zirconia nanoparticles have an antifungal effect, which could be incorporated in the repair material for repairing denture bases and in PMMA removable prostheses as a possible approach for denture stomatitis prevention.

Photocatalytic activity against azo dye and cytotoxicity on MCF-7 cell lines of zirconium oxide nanoparticle mediated using leaves of Lagerstroemia speciosa.

Metal oxide nanoparticles are gaining interest in recent years. The present paper explains about the green synthesis of zirconium oxide nanoparticles (ZrO NPs) mediated from the leaves of Lagerstroemia speciosa. The prepared ZrO NPs were characterized by UV-vis spectroscopy, FT-IR, X-ray diffraction analysis (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and Thermogravimetric Analysis (TGA). The photocatalytic activity of ZrO NPs was studied for azo dye by exposing to sunlight. The azo dye was degraded up to 94.58%. Also the ZrO NPs were studied for in vitro cytotoxicity activity against breast cancer cell lines-MCF-7 and evaluated by MTT assay. The cell morphological changes were recorded by light microscope. The cells viability was seen at 500µg/mL when compared against control. Hence the research highlights, that the method was simple, eco-friendly towards environment by phytoremediation activity of the azo dye and cytotoxicity activity against MCF-7 cell lines. Hence the present paper may help to further explore the metal nanoparticle for its potential applications.

A sensitive determination of terbutaline in pharmaceuticals and urine samples using a composite electrode based on zirconium oxide nanoparticles.

An accurate and precise determination of terbutaline has been carried out using a glassy carbon electrode (GCE) modified with a composite of multi-walled carbon nanotubes (MWCNTs) and nanoparticles of zirconium oxide (ZrO2NPs). Energy dispersive X-ray and scanning electron microscopic techniques were utilized for the characterization of the composite layer. Terbutaline exhibited a broad oxidation peak at 770mV on a GCE. However, MWCNTs/GCE presented an electrocatalytic effect toward the oxidation of terbutaline with a better anodic peak at 660mV. Furthermore, the electrochemical behavior of terbutaline has greatly been improved at a GCE modified with a composite of MWCNTs and nanoparticles of ZrO2. The ZrO2NPs/MWCNTs/GCE exhibited a sharp anodic wave at 645mV with a large enhancement of the current response for terbutaline. Square wave voltammetry (SWV) was performed for the determination of terbutaline at ZrO2NPs/MWCNTs/GCE. A linear plot was obtained for the current responses of terbutaline against concentrations in the range of 10-160nM yielding a detection limit of 2.25nM (based on 3Sb/m). Improved voltammetric behavior, long-time stability and good reproducibility were obtained for terbutaline at the proposed electrode. A mean recovery of 101.2% with an RSD% of 1.9 was obtained for the analysis of the drug formulation. The accurate and precise quantification of terbutaline makes the ZrO2NPs/MWCNTs/GCE system of great interest for monitoring its therapeutic use.

In vivo genotoxicity assessment of titanium, zirconium and aluminium nanoparticles, and their microparticulated forms, in Drosophila.

As in vivo system, we propose Drosophila melanogaster as a useful model for study the genotoxic risks associated with nanoparticle exposure. In this study we have carried out a genotoxic evaluation of titanium dioxide (TiO2), zirconium oxide (ZrO2) and aluminium oxide (Al2O3) nanoparticles and their microparticulated forms in D. melanogaster by using the wing somatic mutation and recombination assay. This assay is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3, can lead to the formation of mutant clones in treated larvae, which are expressed as mutant spots on the wings of adult flies. Third instar larvae were feed with TiO2, ZrO2 and Al2O3 nanoparticles, and their microparticulated forms, at concentrations ranging from 0.1 to 10mM. Although a certain level of aggregation/agglomeration was observed in solution, it must be noted than the constant digging activity of larvae ensures that treated medium pass constantly through the digestive tract ensuring exposure. The results showed that no significant increases in the frequency of all spots (e.g. small single, large single, twin, total mwh and total spots) were observed, indicating that these nanoparticles were not able to induce genotoxic activity in the wing spot assay of D. melanogaster. Negative data were also obtained with the microparticulated forms. This indicates that the nanoparticulated form of the selected nanomaterials does not modify the potential genotoxicity of their microparticulated versions. These in vivo results contribute to increase the genotoxicity database on the TiO2, ZrO2 and Al2O3 nanoparticles.