The synthesis and characterization of hybrid structures obtained by coating Fe3O4 magnetic nanoparticles from water based nanofluid with a polypyrrole (PPy) layer are reported. The thin amorphous layer of polypyrrole surrounding the crystalline magnetic core was observed by HRTEM. The FTIR spectra of the nanocomposites show that the absorption bands characteristic for pyrrole ring vibrations significantly shifted to lower frequencies in the nanocomposite spectra, which indicates a higher degree of oxidation of the PPy shell covering the magnetite as compared with conventional PPy. The existence of superparamagnetism in the investigated nanocomposites is evidenced by the missing hysterezis loop in the magnetization versus applied magnetic field dependences. The comparison between the physical size of nanoparticles determined from TEM analysis and the magnetic size deduced from magnetization measurements is discussed. The surface modification of magnetite by polypyrrole coating results in an increase in the saturation magnetization and of the apparent magnetic diameter of the nanoparticles. This novel effect is attributed to a charge transfer process from the conducting polymer to the surface iron ions of magnetite, producing an increase in the surface contribution to the overall magnetic moment of the nanoparticles.
Abstract:The low rate of survival for patients diagnosed with glioblastoma may be attributed to the existence of a subpopulation of cancer stem cells. These stem cells have certain properties that enable them to resist chemotherapeutic agents and ionizing radiation. Herein, we show that temozolomide-loaded gold nanostructures are efficient in reducing chemoresistance and destroy 82.7% of cancer stem cells compared with a 42% destruction rate using temozolomide alone. Measurements of in vitro cytotoxicity and apoptosis indicate that combination with gold facilitated the ability of temozolomide, an alkylating drug, to alter the resistance of these cancer stem cells, suggesting a new chemotherapy strategy for patients diagnosed with inoperable recurrent malignant glioma.
Composite core-shell nanoparticles may have morpho-structural, magnetic, and optical (photoluminescence (PL)) properties different from each of the components considered separately. The properties of Fe3O4–TiO2 nanoparticles can be controlled by adjusting the titania amount (shell thinness). Core–shell nanoparticles were prepared by seed mediated growth of semiconductor (TiO2) through a modified sol-gel process onto preformed magnetite (Fe3O4) cores resulted from the co-precipitation method. The structure and morphology of samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), and high resolution-TEM respectively. X-ray photoelectron spectroscopy was correlated with ICP-AES. Magnetic measurements, optical absorption spectra, as well as PL spectroscopy indicate the presence of a charge/spin transfer from the conduction band of magnetite into the band gap of titania nanocrystals. The process modifies both Fe3O4 and TiO2 magnetic and optical properties, respectively.
The aim of the present study was to obtain and to investigate nano forsterite and nano forsterite biocomposites for biomedical application. New self-curing forsterite biocomposites were obtained by mixing nano forsterite powder (5, 15, 30, 50, 70 wt %) with 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) monomers. The new nano forsterite biocomposites were investigated for mechanical properties: compressive strength (CS) (143-147.12 MPa), compressive modulus (CM) (1.67-2.75 GPa), diametral tensile strength (DTS) (27.33-31.55 MPa), flexural strength (FS) (59.47-83.20 MPa) and flexural modulus (FM) (2.05-8.60 GPa). Increases of CS, DTS, FS with increasing amount of forsterite were observed up to 50 wt %. The highest CM and FM values were registered for 70 wt % and a direct correlation between the forsterite volume fraction (%) was observed. SEM micrographs revealed the morphology of surface of fractured biocomposites after CS test. XPS indicated that these biocomposites promoted the hydroxyapatite formation on their surface immersed in simulated body fluid (SBF). AFM images showed that the growth of the hydroxyapatite layer occurs with a preferred orientation on the surface of forsterite biocomposites after immersion in SBF. Incorporation of nano forsterite in the polymer matrix (bis-GMA/TEGDMA) did show osteoblast adhesion and proliferation was improved on nano forsterite biocomposites. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1290-1301, 2016.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.