RESUMO
Polyacrylic acid (PAA)-coated lanthanide oxide (Ln2O3) nanoparticles (NPs) (Ln = Tb and Ho) with high colloidal stability and good biocompatibility were synthesized, characterized, and investigated as a new class of negative (T2) magnetic resonance imaging (MRI) contrast agents at high MR fields. Their r2 values were appreciable at a 3.0 T MR field and higher at a 9.4 T MR field, whereas their r1 values were negligible at all MR fields, indicating their exclusive induction of T2 relaxations with negligible induction of T1 relaxations. Their effectiveness as T2 MRI contrast agents at high MR fields was confirmed from strong negative contrast enhancements in in vivo T2 MR images at a 9.4 T MR field after intravenous administration into mice tails.
RESUMO
One-dimension Tb2O3-modified ZnO nanowires were synthesized via water-glycerol binary thermal route. The X-ray diffraction (XRD) patterns demonstrated that the Tb2O3-modified ZnO was pure phase with high crystallinity. The Energy Dispersive Spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed the chemical compositions of Tb2O3-modified ZnO. The images of field-emission electron microscopy (FESEM) indicated that the Tb2O3-modified ZnO was one-dimension nanowires with a diameter of â¼40-100 nm. N2 adsorption/desorption measurements and BET analysis were used to revealed the specific surface area and pore size of Tb2O3-modified ZnO. The images of Transmission Electron Microscope (TEM) and High-Resolution Transmission Electron Microscopy (HRTEM) further showed that the highly uniform heterojunctions had been successfully obtained. The sensitivity and response/recovery time of 3 at% Tb2O3-modified ZnO tested at 200 °C were â¼123 and 73s/50s to 50 ppm 1,2-propanediol, respectively. In addition, the detection limit was as low as 1 ppm. Under UV irradiation, the sensitivity was further improved to 152 while the response/recovery time was shortened to 67s/23s. The morphology of one-dimension Tb2O3-modified ZnO nanowires, the increase of oxygen-deficient region in ZnO and the formation of p-n heterojunction enhanced the properties of 1,2-propanediol-sensing synergistically.
RESUMO
The synthesis of inner transition metal nanoparticles via an ecofriendly route is quite difficult. This study, for the first time, reports synthesis of terbium oxide nanoparticles using fungus, Fusarium oxysporum. The biocompatible terbium oxide nanoparticles (Tb2O3 NPs) were synthesized by incubating Tb4O7 with the biomass of fungus F. oxysporum. Multiple physical characterization techniques, such as UV-visible and photoluminescence spectroscopy, TEM, SAED, and zeta-potential were used to confirm the synthesis, purity, optical and surface characteristics, crystallinity, size, shape, distribution, and stability of the nanoemulsion of Tb2O3 NPs. The Tb2O3 NPs were found to inhibit the propagation of MG-63 and Saos-2 cell-lines (IC50 value of 0.102µg/mL) and remained non-toxic up to a concentration of 0.373µg/mL toward primary osteoblasts. Cell viability decreased in a concentration-dependent manner upon exposure to 10nm Tb2O3 NPs in the concentration range 0.023-0.373µg/mL. Cell toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, and FACS analysis. Morphological examinations of cells revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The level of ROS within the cells-an indicator of oxidative stress was significantly increased. The induction of apoptosis at concentrations ≤IC50 was corroborated by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining (DNA damage and nuclear fragmentation). Flow-cytometric studies indicated that the response was dose dependent with a threshold effect.