Nearly monodispersed NaGdF4/Ho–Yb upconversion
nanoparticles (UCNPs) are synthesized by thermolysis of respective
rare earth oleates. UCNPs are made biocompatible by mesoporous silica
(m-SiO2) coating. These particles exhibit red and green
bands in the visible range upon excitation at 980 nm laser. Interestingly,
because of the presence of Ho3+ ions, these UCNPs can be
excited via UV–vis light in addition to the 980 nm near infrared
light. A systematic study is carried out to demonstrate the use of
these UCNPs as drug (DOX) carriers. Toxicity studies and bio-imaging
using DOX-loaded UCNPs have been demonstrated. UCNPs are also radiolabeled
with 177Lu using m-SiO2 coating to demonstrate
its potential application as a carrier of the therapeutic radionuclide
in vivo for radionuclide therapy. Lu-177 adsorption studies are carried
out extensively in order to understand the nature of adsorption, and
it is found to be a combination of Langmuir and Freundlich isotherm
models. Kinetics of adsorption of Lu3+ ions on the m-SiO2 coating of UCNPs is studied. Overall, the synthesis and physicochemical
characterization of NaGdF4/Ho–Yb@m-SiO2 upconversion nanocrystals and their potential utilities in multimodal
biomedical applications are amply demonstrated.
Monodispersed core@shell γ-Fe2O3@Mn
x
O
y
nanoparticles
have been prepared through thermolysis of iron and manganese oleate.
Further, these prepared nanoparticles are coated with biocompatible
substances such as silica and polyethylene glycol. These particles
are highly biocompatible for different cell lines such as normal and
cancer cell lines. The nanoparticles are used as hyperthermia agents,
and successful hyperthermia treatment in cancer cells is carried out.
As compared to γ-Fe2O3@SiO2, γ-Fe2O3@Mn
x
O
y
@SiO2 shows the enhanced
killing of cancer cells through hyperthermia. In order to make them
potential candidates for targeting to cancer cells, folic acid (FA)
is tagged to the nanoparticles. Fluorescein isothiocyanate (FITC)
is also tagged onto these nanoparticles for imaging. The developed
γ-Fe2O3@Mn
x
O
y
@SiO2 nanoparticle can act
as a single entity for therapy through AC magnetic field, imaging
through FITC and targeting through folic acid simultaneously. This
is the first report on this material, which is highly biocompatible
for hyperthermia, imaging, and targeting.
Herein, we present the synthesis and thermal treatment effect of Hematite (α-Fe2O3). Hematite nanoparticles were prepared by repeated calcination of a precursor obtained from Fe(NO3)3.9H2O and Hexamethylenetetramine (HMTA). Thermal treatment of the precursor at 400 °C for 4 h, resulted in the formation of Fe3O4 nanoparticles, which on repeated calcination at 400 °C, 500 °C and 600 °C, resulted in α-Fe2O3 nanoparticles. Synthesized samples were characterized by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy and UV–vis spectroscopy techniques. XRD result reveals the formation of cubic Fe3O4 phase at 400 °C, which is transformed into rhombohedral α-Fe2O3 polymorphs on repeated calcination. Crystallinity of the α-Fe2O3 is enhanced on repeated calcination up to 500 °C after that it gets slightly amorphized at 600 °C. Raman and FTIR results further corroborate the XRD result. Optical band gap of most crystalline α-Fe2O3, as estimated from UV–vis results, is 1.87 eV. Urbach energy of the samples has been calculated from absorption data, which shows the minimum value for most crystalline material. These findings demonstrate the close relation between structure and optical properties of α-Fe2O3.
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.