Synthesis of Fe3O4/ZnO Core-shell Nanoparticles for Photodynamic Therapy Applications

2010 ◽  
Vol 1257 ◽  
Author(s):  
Juan C. Beltran Huarac ◽  
Surinder P. Singh ◽  
Maharaj S. Tomar ◽  
Sandra Peňa ◽  
Luis Rivera ◽  
...  

AbstractThe use of nanoparticles as carriers of photosensitizer (PS) molecules for photodynamic therapy (PDT) has attracted much interest on core-shell nanosize structures. Herein, we used a simple aqueous solution method to synthesize Fe3O4/ZnO core-shell nanoparticles. X-ray diffraction (XRD) analyses showed the presence of well defined peaks corresponding to Fe3O4 and ZnO in as-synthesized nanocrystals. Vibrating sample magnetometer (VSM) measurements showed that these nanoparticles exhibited superparamagnetic behavior of the core with no coercivity nor remanence. X-ray photoelectron spectroscopy (XPS) analyses revealed the presence of Zn1/2 and Zn3/2 species on the surface of nanocrystals. Photoluminescence measurements showed excitonic emission of ZnO co-existing with a weak and broad defect- related green emission at room temperature. The generation of singlet oxygen was monitored via the photooxidation of diphenyl-1,3-isobenzofuran (DPBF) with different light sources, followed by absorption spectroscopy at 409 nm. The capability of synthesized nanoparticles to generate singlet oxygen has also been verified.

2015 ◽  
Vol 7 (12) ◽  
pp. 5053-5059 ◽  
Author(s):  
Na-Na Li ◽  
Tian-Fang Kang ◽  
Jing-Jing Zhang ◽  
Li-Ping Lu ◽  
Shui-Yuan Cheng

In this study, Fe3O4@ZrO2 magnetic core–shell nanoparticles (NPs) were synthesized and were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).


2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.


2021 ◽  
Vol 19 (10) ◽  
pp. 82-88
Author(s):  
Duaa A. Uamran ◽  
Qasim Hassan Ubaid ◽  
Hammad R. Humud

Core-shell nanoparticles (SiO2/Ag) were manufactured by using a two-step process: Electric detonation of Ag. Wire in colloidal solution particles then by using laser pulses, nanoparticles are released. The structural features of these nanoparticles were checked by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The (XRD) study showed the progressive coverage of SiO2/Ag by nanoparticles according to the energies of the laser pulse. Measurements of morphology and EDX confirmed the Core/shell structure with particle size at the nano level. It confirmed that preliminary analysis consists of a SiO2 core and an Ag shell from FESEM. The surface of the microscopic balls (SiO2) has been covered completely and homogeneously with Ag nanoparticles, Moreover, Ultraviolet-Visible, and by optical absorption spectroscopy, the Nanoparticles with core crust SiO2/Ag showed excellent photocatalytic activities at various concentrations and laser pulse energy.


2014 ◽  
Vol 118 (46) ◽  
pp. 26621-26628 ◽  
Author(s):  
Won Hui Doh ◽  
Vasiliki Papaefthimiou ◽  
Thierry Dintzer ◽  
Véronique Dupuis ◽  
Spyridon Zafeiratos

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
M. S. Pudovkin ◽  
D. A. Koryakovtseva ◽  
E. V. Lukinova ◽  
S. L. Korableva ◽  
R. Sh. Khusnutdinova ◽  
...  

Core Pr3+ : LaF3 (CPr = 1%) plate-like nanoparticles (nanoplates), core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanoplates, core Pr3+ : LaF3 (CPr = 1%) sphere-like nanoparticles (nanospheres), and core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanospheres were synthesized via the coprecipitation method of synthesis. The nanoparticles (NPs) were characterized by means of transmission electron microscopy, X-ray diffraction, and optical spectroscopy. The formation of the shell was proved by detecting the increase in physical sizes, sizes of coherent scattering regions, and luminescence lifetimes of core/shell NPs comparing with single core NPs. The average physical sizes of core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were 62.2 ± 0.9, 74.7 ± 1.2, 13.8 ± 0.9 and 22.0 ± 1.2 nm, respectively. The formation of the NP shell led to increasing of effective luminescence lifetime τeff of the 3P0 state of Pr3+ ions for the core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres the values of τeff were 2.3, 3.6, 3.2, and 4.7 μsec, respectively (at 300 K). The values of absolute sensitivity Sa for fluorescence intensity ratio (FIR) thermometry was 0.01 K−1 at 300 K for all the samples. The FIR sensitivity can be attributed to the fact that 3P1 and 3P0 states share their electronic populations according to the Boltzmann process. The values of Sa for lifetime thermometry for core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were (36.4 ± 3.1) · 10−4, (70.7 ± 5.9) · 10−4, (40.7 ± 2.6) · 10−4, and (68.8 ± 2.4) · 10−4 K−1, respectively.


Author(s):  
Heng Lu ◽  
Bing Gu

In this work, the Au@Ag bimetallic core–shell nanostructures were synthesized by a seed-mediated growth. The crystal structure, morphology, elemental composition, atomic concentration, and absorption spectrum of the as-synthesized nanoparticles were characterized by means of X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible linear absorption spectrum, respectively. The femtosecond third-order optical nonlinearities of nanoparticle dispersions were investigated by carrying out the femtosecond-pulsed [Formula: see text]-scan measurements at 800[Formula: see text]nm. The experimental results indicate that Au@Ag core–shell nanoparticles exhibit the positive refractive nonlinearity and negative absorptive nonlinearity. The third-order nonlinear refraction indexes of Au and Au@Ag nanoparticles are measured to be [Formula: see text] and [Formula: see text][Formula: see text]cm2/GW, respectively. The results show that the bimetallic nanoparticle has potential possibility in nonlinear photonic applications.


2006 ◽  
Vol 933 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

ABSTRACTGermanium nanoparticles are grown on HfO2 substrates by hot-wire chemical vapor deposition (HWCVD). The oxidation and thermal stability of these unmodified Ge nanoparticles are determined with X-ray photoelectron spectroscopy (XPS). Core-shell nanoparticles were then prepared by growing the Ge cores with HWCVD and selectively growing Si or C shell layers on the Ge cores by conventional CVD. The formation of core-shell nanoparticles was monitored with XPS and low energy ion scattering. Large differences are observed in the thermal stability and oxide formation for unmodified Ge and the different core-shell nanoparticles.


Sign in / Sign up

Export Citation Format

Share Document