Application of NIR (near-infrared) emitting transition metal complexes in biomedicine is a rapidly developing area of research. Emission of this class of compounds in the “optical transparency windows” of biological...
In this work, we
report on the synthesis of the two highly thermosensitive
Eu complexes ([(tta)3Eu(NN1)] (Eu1) and [(tta)3Eu(NN2)] (Eu2), where tta is thenoyltrifluoroacetone,
NN1 is 3-phenyl-2-(pyridin-2-yl)pyrido[2,1-a]pyrrolo[3,2-c]isoquinoline, and NN2 is 1-phenyl-2-(pyridin-2-yl)-1H-phenanthro[9,10-d]imidazole),
and preparation of luminescent thermosensitive nanomaterial (latex
nanothermometer, LNT). LNT design and preparation were based on the
application of Eu2 and copolymerization of butyl and
methyl methacrylates in the presence of the complex, surfactant (cetyltrimethylammonium
bromide), and cosurfactant (acetone). Optimization of nanoemulsion
polymerization conditions allowed us to obtain strongly luminescent
nanoparticles with a narrow size distribution (D =
75 nm; PDI = 0.05). Moreover, the resulting LNT particles feature
nonuniform distribution of Eu2, which localizes mainly
inside the nanoparticles while the outer layer lacks the complex.
As a result, the developed LNT demonstrates monoexponential luminescence
decays with a lifetime temperature sensitivity up to 0.84%/K and resolutions
of 0.26 K comparable to or exceeding existing analogues together with
complete reversibility in cycling experiments.
Quasi-spherical nanoparticles of ZrO2 containing EuO1.5 from 2 to 15 mol.% were synthesized from the chlorides of the corresponding metals under hydrothermal conditions. The structural changes of Zr1–xEuxO2–0.5x (x = 0.02 ÷ 0.15) nanoparticles depending on the content of europium (III) ions were studied using the complementary methods (X-ray diffraction, electron microdiffraction, Raman and photoluminescence spectroscopy). It was shown that increasing the Eu3+ concentration in the Zr1–xEuxO2–0.5x nanoparticles leads to a transition from the equilibrium monoclinic zirconia phase to metastable tetragonal and cubic polymorphic modifications. In this case, the size of the nanoparticles decreases from 11.5 nm to 9 nm; the specific surface area grows from 80.2 to 111.3 m2/g, and the electrokinetic potential increases monotonously from −8.7 to 16.3 mV. The evolution of the phase composition of Zr1–xEuxO2-0.5x nanoparticles from monoclinic to tetragonal/cubic allomorphs with an increase in the molar fraction of stabilizer ions was correlated with changes in the sublevel structure of 5D0 → 7F2 and 5D0 → 7F4 optical transitions for Eu3+ in the luminescence spectra. Besides, for the nanoparticles obtained by hydrothermal synthesis from chlorides, the quantum efficiency does not exceed 3%. According to the M.T.T. assay, as a result of three-day human fibroblast cultivation in the aqueous dispersion of Zr1–xEuxO2–0.5x (x = 0.02 ÷ 0.15) nanoparticles, the proliferation activity of the cells is maintained, indicating that they do not have cytotoxic properties. Such nanoparticles can be used in organic–inorganic composites for medical applications in order to strengthen the polymer scaffolds and visualize changes in their structure within time.
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.