Search

Using the polymerization-induced phase separation (PIPS) method, bilayer polymer-dispersed liquid crystal (PDLC) films with a PDLC-PVA-PDLC structure were prepared in this work. It was found that all PDLC performance indexes were affected by polymer mesh size after comparing the microscopic morphology and electro-optical properties of samples with different monomer ratios. Gd2O3 nanoparticles and rhodamine B base fluorescent dyes introduced into the bilayer PDLC optimized the samples' electro-optical properties and developed new functionalities. In addition, the bilayer PDLC doped with Gd2O3 and rhodamine B base held excellent progressive driving functions as well as stable durability properties. Samples doped with Gd2O3 nanoparticles and rhodamine B base also produced excellent anti-counterfeiting effects under UV irradiation at different angles, further exploiting the application potential of PDLC. [ABSTRACT FROM AUTHOR]

Using the polymerization-induced phase separation (PIPS) method, bilayer polymer-dispersed liquid crystal (PDLC) films with a PDLC-PVA-PDLC structure were prepared in this work. It was found that all PDLC performance indexes were affected by polymer mesh size after comparing the microscopic morphology and electro-optical properties of samples with different monomer ratios. Gd2O3 nanoparticles and rhodamine B base fluorescent dyes introduced into the bilayer PDLC optimized the samples’ electro-optical properties and developed new functionalities. In addition, the bilayer PDLC doped with Gd2O3 and rhodamine B base held excellent progressive driving functions as well as stable durability properties. Samples doped with Gd2O3 nanoparticles and rhodamine B base also produced excellent anti-counterfeiting effects under UV irradiation at different angles, further exploiting the application potential of PDLC.

We have prepared silica matrix with hexagonal symmetry of pores (SBA-15) and loaded it with anticancer drug 5-Fluorouracil (5-FU) to promote it as a drug delivery system. Gd2O3 nanoparticles were incorporated into the matrix to enhance nanosystems applicability as contrast agent for MRI, thus enabled this nanocomposite to be used as multifunctional nano-based therapeutic agent. Drug release profile was obtained by UV-VIS spectroscopy, and it indicates the prolongated release of 5-FU during the first hours and the total release after 5 h. The cytotoxicity tests using MTT-assay, fluorescent microscopy, bright-field microscopy, and flow cytometry were carried out using human glioma U87 MG cells and SK BR 3 cells. The nanocomposite with anticancer drug (Gd2O3/SBA-15/5FU) showed toxic behaviour towards studied cells, unlike nanocomposite without drug (Gd2O3/SBA-15) that was non-toxic. Our drug delivery system was designed to minimalize negative effect of Gd3+ ions at magnetic resonance imaging and drug 5-FU on healthy cells due to their encapsulation into biocompatible silica matrix, so the Gd3+ ions are more stable (in comparison to chelates), lower therapeutic dose of 5-FU is needed and its prolongated release from silica pores was confirmed. Very good T1 contrast in MR images was observed even at low concentrations, thus this nanosystem can be potentially used as contrast imaging agent.

Herein, we report the biocompatible amine-functionalized gadolinium oxide nanoparticles (Gd2O3 NPs) for the possibility of electrochemical detection of Vibrio cholerae (Vc) cells. The microwave irradiation process is applied to synthesize Gd2O3 NPs. The amine (NH2) functionalization is carried out via overnight stirring with 3(Aminopropyl)triethoxysilane (APTES) at 55 °C. The size of NPs amine functionalized APETS@Gd2O3 NPs are determined by transmission electron microscopy (TEM). APETS@Gd2O3 NPs are further electrophoretically deposited onto indium tin oxide (ITO) coated glass substrate to obtain working electrode surface. The monoclonal antibodies (anti-CT) specific to cholera toxin associated to Vc cells are covalently immobilized onto the above electrodes using EDC-NHS chemistry and further BSA is added to obtain the BSA/anti-CT/APETS@Gd2O3/ITO immunoelectrode. Further, this immunoelectrode shows the response for cells in CFU range from 3.125 × 106 to 30 × 106 and is very selective with sensitivity and LOD 5.07 mA CFUs mL cm−2 and 0.9375 × 106 CFU respectively. To establish a future potential for APTES@Gd2O3 NPs in field of biomedical applications and cytosensing, the effect of APTES@Gd2O3 NPs on mammalian cells is also observed using in vitro cytotoxicity assay and cell cycle analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eu3+/Gd 2 O 3 @HSiO 2 /NCO was prepared using step-wise synthetic approach. • The multifunctional fluorescence sensor can recognize Cr6+highly sensitively. • Cr6+ treatment causes significant changes in sum of fluorescence intensity changes. • Determination of Cr6+ in real samples was examined. We developed a multi-emission fluorescence sensor based on hybridizing two different fluorescent centers, which provides a built-in correction to remove environmental effects. Eu3+ doped Gd 2 O 3 nanoparticles were embedded in the silica hollow spheres while the fluorophore naphthalene derived molecules were covalently linked to the surface of silica to form multi-emission fluorescence sensors (Eu3+/Gd 2 O 3 @HSiO 2 /NCO). With a detection limit of 3.8 nM, the nanosensor offers an effective platform for reliable Cr6+ detection. The obtained accuracy is considerably lower than the maximum level of Cr6+ in drinking water permitted by the U.S. Environmental Protection Agency (EPA). The prepared Eu3+/Gd 2 O 3 @HSiO 2 /NCO inherited simultaneously the excellent luminescence performance of Eu3+/Gd 2 O 3 and the fluorophore group and exhibited interesting structural and fluorescence stability in aqueous solution. A higher enhancement of fluorescence emission stemming from an intrinsic structure of Eu3+/Gd 2 O 3 nanoparticles was observed by adding Cr6+ ions as opposed to naphthalene molecules. There was a good linear relationship between the sum of fluorescence intensity changes (ΔI 330 + ΔI 610) and the Cr6+ concentration in the range of 0.1–1.0 ppm. The nanosensor fabricated by this method showed good reversibility, enabling the rapid detection of Cr6+ in real water samples. As a result of this groundbreaking study, we are able to develop an idea for building a multifunctional fluorescent probe, with potential applications in biotechnology, food analysis, and environmental analysis. [ABSTRACT FROM AUTHOR]

Herein, we report the biocompatible amine-functionalized gadolinium oxide nanoparticles (Gd2O3 NPs) for the possibility of electrochemical detection of Vibrio cholerae (Vc) cells. The microwave irradiation process is applied to synthesize Gd2O3 NPs. The amine (NH2) functionalization is carried out via overnight stirring with 3(Aminopropyl)triethoxysilane (APTES) at 55 °C. The size of NPs amine functionalized APETS@Gd2O3 NPs are determined by transmission electron microscopy (TEM). APETS@Gd2O3 NPs are further electrophoretically deposited onto indium tin oxide (ITO) coated glass substrate to obtain working electrode surface. The monoclonal antibodies (anti-CT) specific to cholera toxin associated to Vc cells are covalently immobilized onto the above electrodes using EDC-NHS chemistry and further BSA is added to obtain the BSA/anti-CT/APETS@Gd2O3/ITO immunoelectrode. Further, this immunoelectrode shows the response for cells in CFU range from 3.125 × 106 to 30 × 106 and is very selective with sensitivity and LOD 5.07 mA CFUs mL cm−2 and 0.9375 × 106 CFU respectively. To establish a future potential for APTES@Gd2O3 NPs in field of biomedical applications and cytosensing, the effect of APTES@Gd2O3 NPs on mammalian cells is also observed using in vitro cytotoxicity assay and cell cycle analysis.

Nanostructured Gd 2 O 3 has been synthesized using the leaf broth of Annona reticulate. The formation of nanoparticles is confirmed by XRD and TEM analysis. UV–visible and PL studies are employed to characterize the optical nature of the samples and the thermal analysis of the as prepared material has been performed to ascertain the proper annealing temperature. XRD pattern shows cubic structure with average particle size of about 25 nm. FTIR spectra reveal the possible biomolecules responsible for the formation of nanoparticles and their stabilization. Raman spectrum with characteristic band located at 360 cm−1 for the F g mode supports the cubic phase of the nanostructured Gd 2 O 3. Biocompatibility of synthesized nanoparticles is evaluated by carrying out the cytotoxic test against normal fibroblast cell lines and surviving fraction of normal cell lines are found to be above 75% up to a concentration of 50μg/mL. The antimicrobial activity of developed nanoparticles are screened against K. Pneumonae and S.aureus bacterial cell lines and substantial inhibition zones are observed in the dose dependent study. Moreover, this study also investigates the antioxidant efficacy of Gd 2 O 3 nanoparticles using DPPH and superoxide free radical scavenging assays. With a concentration of 20μg/mL of the synthesized nanoparticles 70% scavenging is observed. The method of synthesis is simple, cost-effective and unexplored as it follows an ecofriendly protocol for the production of biologically active nanostructured Gd 2 O 3. • Biofabrication of Gd 2 O 3 nanoparticles. • The synthesized nanoparticles display better biocompatible nature on L929 cell lines. • Functionalized Gd 2 O 3 NPs exhibits moderate antibacterial activity. • Advanced free radical scavenging activity makes nano Gd 2 O 3 as better antioxidants. • Abstract. [ABSTRACT FROM AUTHOR]

• The influence of Mn substitution on the structural, magnetic and magnetocaloric characteristics of Gd 2 O 3 powders. • The lattice parameter slightly decreases with the Mn doping degree. • The maximum of magnetic entropy changes - Δ S M max were found 7.344 and 7.977 J/kg K respectively for x = 0.00 and x = 0.10 at µ 0 H = 5 T. Magnetic cooling is considered to be an important component of future green refrigeration. On this subject, rare earth oxides (RE 2 O 3) are seen as a promising class of magnetic materials for low-temperature magnetic cooling technology. In this work, we report the influence of Mn substitution on the structural, magnetic and magnetocaloric characteristics of Gd 2 O 3 powders synthesized by sol–gel route. Structural analysis using Rietveld refinement technique confirmed the cubic-bixbyite structure with the Ia 3 ¯ space group. The lattice parameter slightly decreases with the Mn doping degree. Temperature dependent magnetization measurements demonstrated a paramagnetic behavior sustained in Gd 2-x Mn x O 3 in the whole temperature range of 2–400 K and the presence of weak antiferromagnetic interactions at low temperature (≤2K). The measured hysteresis loops are linear and completely reversible (2 K), which is typical for paramagnetic system and suitable for cryogenics magnetic refrigeration. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with increasing magnetic field. [ABSTRACT FROM AUTHOR]

In this study, we report the synthesis and characterization of 3,5-Diiodo-L-tyrosine (DLT)-coated gadolinium oxide (Gd2O3) nanoparticles. The bonding status of DLT-coated Gd2O3 nanoparticles (DLT-NPs) were confirmed by Fourier transform infrared (FT-IR) absorption spectra and thermogravimetric analysis (TGA). The surface coating amount was estimated to be 73% in weight percent from a TGA. High-resolution transmission electron microscope (HR-TEM) shows that DLT-NPs were spherical in shape with an average diameter 2 nm. The MR relaxivity measurements confirmed that the DLT-NPs have higher r1 = 9.24 s-1 mM-1 than commercially available contrast agents. Furthermore, the bio-compatibility of the DLT-NPs were measured by cytotoxicity test, which has demonstrated that the cell viability reached up to 60% with Gd concentrations up to 50 μM for both DU145 and NCTC1469 cell lines, making them a promising candidate for biomedical applications. [ABSTRACT FROM AUTHOR]

We report on the effects of Mn doping on the structural, linear, and nonlinear optical properties of Gd 2-x Mn x O 3 nanoparticles (x = 0.00, 0.03, 0.05, and 0.10). The Gd 2-x Mn x O 3 powders were prepared using sol-gel process. The x-ray diffraction technique shows that the Mn3+ doping results in a small decrease in lattice parameter and an increase in crystallite size. UV–visible measurements were carried out in the wavelength range of 200–800 nm. The direct optical band gap estimated using Tauc model decreases with increasing Mn content from 5.152 to 5.008 eV, while Urbach energy increases from 0.753 to 1.012 eV. Moreover, the insertion of Mn results in a significant enhancement in the optical parameters (refractive index, extinction coefficient, absorption coefficient, dielectric constants (ε ', ε "), optical and electrical conductivity. The dispersion energy (E d) increases from 24.13 to 30.1 eV, while the single oscillator energy (E 0) declines lightly from 10.28 to 9.998 eV with the increase of Mn content. With Mn doping an enhancement in the static linear refractive index (n 0) and high-frequency dielectric constant (ε ∞) were also observed. Analysis of linear and nonlinear optical parameters shows that the presence of manganese enhanced the linear optical susceptibility (χ(1)), third-order non-linear susceptibility (χ(3)), and non-linear refractive index (n 2). These optical results show the potential applications of Gd 2-x Mn x O 3 nanoparticles (x = 0.00, 0.03, 0.05 and 0.10) in various optical devices. • We report on the effects of Mn doping on the structural, linear, and nonlinear optical properties of Gd 2-x Mn x O 3 nanoparticles. • The x-ray diffraction technique shows that the Mn3+ doping results in a small decrease in lattice parameter and an increase in crystallite size. • The insertion of Mn results in a significant enhancement of the optical parameters. [ABSTRACT FROM AUTHOR]

The magnetocaloric effect (MCE) of hybrid nanostructure consisting of fine gadolinium oxide (Gd2O3) nanoparticles with diameter up to 12 nm loaded into the pores of the periodically ordered mesoporous silica with cubic (SBA-16) symmetry were investigated. These studies were mainly based on heat capacity Cp measurements in temperature range 0.4-55 K under external magnetic field from 0 to 9 T. After the subtraction of lattice heat capacity contribution, the maximum of isothermal magnetic entropy change SM = 33 J/(K kg) and value of refrigerant capacity power RCP 170 J/kg was obtained at temperature 2.5 K. Our findings confirm that this kind of nanocomposites can be promising for future refrigeration technology applications. [ABSTRACT FROM AUTHOR]

We investigated nanocargo-delivery magnetic platform composed of spherical Gd2O3 particles, loaded together with cytostatic drug 5-fluorouracil (5-FU) in periodic mesoporous silica matrix. The system under study combined the advantages of high surface area and pore volume of mesoporous silica cargo with the advantages of magnetic separability and targeted drug delivery, provided by magnetic Gd2O3 nanoparticles. The sample was characterized by HRTEM (High-Resolution Transmission ElectronMicroscopy), PXRD (powder X-ray diffraction), elemental analysis, and magnetic measurements by MPMS apparatus. A conventional paramagnetic response was observed in the whole 5-330 K range with high magnetization about 90 emu/g at 50 000 Oe. Effective magnetic moment per formula unit 7.88 μB obtained at room temperature is close to theoretical value 7.94 μB. The released amount of 5-FU represented more than 90% of the loaded one. [ABSTRACT FROM AUTHOR]

We investigated nanocargo-delivery magnetic platform composed of spherical Gd2O3 particles, loaded together with cytostatic drug 5-fluorouracil (5-FU) in periodic mesoporous silica matrix. The system under study combined the advantages of high surface area and pore volume of mesoporous silica cargo with the advantages of magnetic separability and targeted drug delivery, provided by magnetic Gd2O3 nanoparticles. The sample was characterized by HRTEM (High-Resolution Transmission ElectronMicroscopy), PXRD (powder X-ray diffraction), elemental analysis, and magnetic measurements by MPMS apparatus. A conventional paramagnetic response was observed in the whole 5-330 K range with high magnetization about 90 emu/g at 50 000 Oe. Effective magnetic moment per formula unit 7.88 μB obtained at room temperature is close to theoretical value 7.94 μB. The released amount of 5-FU represented more than 90% of the loaded one. [ABSTRACT FROM AUTHOR]

The mononuclear Gd(III) complex, [Gd(L)3(H2O)5] (where L is alizarin yellow R (NaC13H8N3O5)), has been prepared in H2O under reflux condition. The Gd(III) complex has been characterized by elemental analysis and spectroscopic methods (UV–Vis and FT–IR). The Gd2O3 nanoparticles were prepared by the calcination of the Gd(III) complex in air at different temperatures up to 600 °C for 2 h. The calcination temperature was the key parameter which was changed for more investigation. The products were characterized by various methods such as FT–IR, X-ray diffraction analysis and field-emission scanning electron microscopy (FE–SEM). The electrochemical studies of the Gd(III) complex and Gd2O3 nanoparticles were performed in acetonitrile. The voltammograms in the absence and presence of carbon dioxide indicate that [Gd(L)3(H2O)5] and Gd2O3 nanoparticles can catalyze the electrochemical reduction of CO2 to CO.

We have prepared silica matrix with hexagonal symmetry of pores (SBA-15) and loaded it with anticancer drug 5-Fluorouracil (5-FU) to promote it as a drug delivery system. Gd 2 O 3 nanoparticles were incorporated into the matrix to enhance nanosystems applicability as contrast agent for MRI, thus enabled this nanocomposite to be used as multifunctional nano-based therapeutic agent. Drug release profile was obtained by UV-VIS spectroscopy, and it indicates the prolongated release of 5-FU during the first hours and the total release after 5 h. The cytotoxicity tests using MTT-assay, fluorescent microscopy, bright-field microscopy, and flow cytometry were carried out using human glioma U87 MG cells and SK BR 3 cells. The nanocomposite with anticancer drug (Gd 2 O 3 /SBA-15/5FU) showed toxic behaviour towards studied cells, unlike nanocomposite without drug (Gd 2 O 3 /SBA-15) that was non-toxic. Our drug delivery system was designed to minimalize negative effect of Gd 3+ ions at magnetic resonance imaging and drug 5-FU on healthy cells due to their encapsulation into biocompatible silica matrix, so the Gd 3+ ions are more stable (in comparison to chelates), lower therapeutic dose of 5-FU is needed and its prolongated release from silica pores was confirmed. Very good T1 contrast in MR images was observed even at low concentrations, thus this nanosystem can be potentially used as contrast imaging agent., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Adriana Zelenakova reports financial support was provided by 10.13039/501100005357Slovak Research and Development Agency., (© 2023 The Authors.)

The non-isothermal decomposition of unirradiated and γ-irradiated hydrated gadolinium acetylacetone with 102 kGy γ-ray absorbed dose was carried out in air and in nitrogen atmospheres and in the temperature range of 25–1000°C. The results indicate that gadolinium acetylacetonate decomposes through four main decomposition steps leading to the formation of intermediate products whose chemical structure is independent of the gas atmosphere applied and on the investigated absorbed dose. The final product at 820°C was found to be Gd2O3irrespective of the gas atmosphere and the irradiation conditions. The non-isothermal data were analyzed using linear Flynn–Wall–Ozawa and non-linear Vyazovkin (VYZ) iso-conversional methods. The results of the application of these free models on the present kinetic data showed that the activation energy,Eais independent of α in a very wide conversion range (0.1–0.9) indicating that the decomposition process is controlled by a unique kinetic model. The results of the model-fitting analysis showed that the decomposition course of the four decomposition steps of hydrated gadolinium acetylacetone was controlled by the D3Jander diffusion model. Pure phase of Gd2O3nanoparticles was obtained by thermal oxidation of γ-irradiated GdAcAc.3 H2O at 800°C for 6 h. X-ray diffraction, transmission electron microscopy (TEM) and atomic force microscopy (AFM) techniques were employed for characterization of the as-synthesized nanoparticles. This is the first attempt to prepare Gd2O3nanoparticles by solid-state thermal decomposition of γ-irradiated hydrated gadolinium acetylacetone. [ABSTRACT FROM AUTHOR]

Abstract: In this report, monodispersed ultra-small Gd2O3 nanoparticles capped with hydrophobic oleic acid (OA) were synthesized with average particle size of 2.9 nm. Two methods were introduced to modify the surface coating to hydrophilic for bio-applications. With a hydrophilic coating, the polyvinyl pyrrolidone (PVP) coated Gd2O3 nanoparticles (Gd2O3-PVP) showed a reduced longitudinal T 1 relaxation time compared with OA and cetyltrimethylammonium bromide (CTAB) co-coated Gd2O3 (Gd2O3-OA-CTAB) in the relaxation study. The Gd2O3-PVP was thus chosen for its further application study in MRI with an improved longitudinal relaxivity r 1 of 12.1 mm − 1 s−1 at 7 T, which is around 3 times as that of commercial contrast agent Magnevist®. In vitro cell viability in HK-2 cell indicated negligible cytotoxicity of Gd2O3-PVP within preclinical dosage. In vivo MR imaging study of Gd2O3-PVP nanoparticles demonstrated considerable signal enhancement in the liver and kidney with a long blood circulation time. Notably, the OA capping agent was replaced by PVP through ligand exchange on the Gd2O3 nanoparticle surface. The hydrophilic PVP grants the Gd2O3 nanoparticles with a polar surface for bio-application, and the obtained Gd2O3-PVP could be used as an in vivo indicator of reticuloendothelial activity. [Copyright &y& Elsevier]

• Nanocomposites with Gd 2 O 3 NPs embedded into regular pores of amorphous SiO 2 matrix. • Magnetic properties and magnetocaloric effect studied by heat capacity measurements. • At cryogenic temperature, the nanocomposites exhibit large magnetocaloric effect. • These are promising candidates for magnetic refrigeration at cryogenic temperature. Structural characteristics and magnetic properties with respect to magnetocaloric effect was studied in the nanocomposite systems consisting of Gd 2 O 3 nanoparticles embedded in the regular pores of amorphous silica matrix. The particles of size 2–16 nm were prepared by nanocasting method within the pores of periodic silica matrices of hexagonal (SBA15 type) and cubic (SBA16 type) symmetries. Magnetocaloric response of the systems was examined in the applied fields up to 9 T in the low temperature region ranging from 0.4 K to 55 K. The data obtained from the measurements of the heat capacity C p (H,T) revealed a peak at temperature below 10 K. Taking into account the superposition principle, the contributions corresponding to the lattice and the magnetic subsystem heat capacities were analyzed separately. The high value of magnetic entropy change |ΔS M | = ~27 JK−1kg−1 and |ΔS M | = 37 JK−1kg−1 for the systems with hexagonal and cubic matrices, respectively were observed at the temperature close to 2 K under field change from 0 to 9 T. The evidence on considerable high |ΔS M | values along with the large surface area of mesoporous silica, easy and reproducible preparation manifest some extra advantages over the conventional refrigeration technology. [ABSTRACT FROM AUTHOR]

A new strategy for designing contrast agents (CAs) based on geometrical confinement will become a competent way to improve the relaxivity of CAs. Herein, a magnetic resonance imaging (MRI) nanoconstruct is fabricated through loading Gd 2 O 3 nanoparticles into mesoporous carbon nanospheres, followed by conjugation of poly(ethylene glycol) (PEG) and the c(RGDyK) peptide (Gd 2 O 3 @OMCN-PEG-RGD), which could prolong the blood circulation half-life as well as improve the tumor-targeting ability. As a result, the Gd 2 O 3 @OMCN-PEG-RGD exhibits an outstandingly high relaxivity ( r 1 = 68.02 mM -1 s -1 ), which is ∼5.3 times higher than that of Gd 2 O 3 nanoparticles ( r 1 = 12.74 mM -1 s -1 ). Afterward, both the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test and H&E staining show that the Gd 2 O 3 @OMCN-PEG-RGD has wonderful biocompatibility in vitro and in vivo. Moreover, the in vivo MR images indicate that the Gd 2 O 3 @OMCN-PEG-RGD could accumulate in the tumor region more rapidly than Gd 2 O 3 @OMCN-PEG. This study presents a facile method to fabricate an MRI CA with excellent T 1 contrast ability based on geometrical confinement and excellent biocompatibility, which could act as an optimal contender for sensitive in vivo tumor imaging with outstanding targeting ability.