Yttrium-Doped Iron Oxide Nanoparticles for Magnetic Hyperthermia Applications

Magnetic nanoparticles of Fe₃O₄ doped by different amounts of Y³⁺ (0, 0.1, 1, and 10%) ions were designed to obtain maximum heating efficiency in magnetic hyperthermia for cancer treatment. Single-phase formation was evident by X-ray diffraction measurements. An improved magnetization value was obtained for the Fe₃O₄ sample with 1% Y³⁺ doping. The specific absorption rate (SAR) and intrinsic loss of power (ILP) values for prepared colloids were obtained in water. The best results were estimated for Fe₃O₄ with 0.1% Y³⁺ ions (SAR = 194 W/g and ILP = 1.85 nHm²/kg for a magnetic field of 16 kA/m with the frequency of 413 kHz). The excellent biocompatibility with low cell cytotoxicity of Fe₃O₄:Y nanoparticles was observed. Immediately after magnetic hyperthermia treatment with Fe₃O₄:0.1%Y, a decrease in 4T1 cells' viability was observed (77% for 35 μg/mL and 68% for 100 μg/mL). These results suggest that nanoparticles of Fe₃O₄ doped by Y³⁺ ions are suitable for biomedical applications, especially for hyperthermia treatment.

AMPK-mediated senolytic and senostatic activity of quercetin surface functionalized Fe3O4 nanoparticles during oxidant-induced senescence in human fibroblasts

Cellular senescence may contribute to aging and age-related diseases and senolytic drugs that selectively kill senescent cells may delay aging and promote healthspan. More recently, several categories of senolytics have been established, namely HSP90 inhibitors, Bcl-2 family inhibitors and natural compounds such as quercetin and fisetin. However, senolytic and senostatic potential of nanoparticles and surface-modified nanoparticles has never been addressed. In the present study, quercetin surface functionalized Fe₃O₄ nanoparticles (MNPQ) were synthesized and their senolytic and senostatic activity was evaluated during oxidative stress-induced senescence in human fibroblasts in vitro. MNPQ promoted AMPK activity that was accompanied by non-apoptotic cell death and decreased number of stress-induced senescent cells (senolytic action) and the suppression of senescence-associated proinflammatory response (decreased levels of secreted IL-8 and IFN-β, senostatic action). In summary, we have shown for the first time that MNPQ may be considered as promising candidates for senolytic- and senostatic-based anti-aging therapies.

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Quercetin surface functionalized magnetite nanoparticles (MNPQ) were synthesized.

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MNPQ eliminated hydrogen peroxide-induced senescent human fibroblasts.

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MNPQ limited senescence-associated proinflammatory responses.

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Senotherapeutic action of MNPQ was accompanied by increased activity of AMPK.

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MNPQ may be useful for senolytic- and senostatic-based anti-aging therapies.

Multifunctional nanocrystalline calcium phosphates loaded with Tetracycline antibiotic combined with human adipose derived mesenchymal stromal stem cells (hASCs)

Osteoconductive drug delivery system composed of nanocrystalline calcium phosphates (Ca10(PO4)6(OH)2/β-Ca3(PO4)2) co-doped with Yb(3+)/Er(3+) ions loaded with Tetracycline antibiotic (TC) was developed. Their effect on human adipose derived mesenchymal stromal stem cells (hASCs) as a potential reconstructive biomaterial for bone tissue regeneration was studied. The XRD and TEM measurements were used in order to determine the crystal structure and morphology of the final products. The characteristics of nanocomposites with the TC and hASCs as potential regenerative materials as well as the antimicrobial activity of the nanoparticles against: Staphylococcus aureus ATCC 25923 as a model of the Gram-positive bacteria, Escherichia coli ATCC 8739 of the Gram-negative bacteria, were shown. These combinations can be a promising material for theranostic due to its regenerative, antimicrobial and fluorescent properties.

A new approach in the synthesis of La(1-x)Gd(x)FeO3 perovskite nanoparticles--structural and magnetic characterization

A series of highly crystalline orthoferrite nanoparticles (type La(1-x)Gd(x)FeO3, where x = 0 to 1) were prepared using the self-combustion method. Extensive studies including X-ray diffraction, Rietveld refinement and Fourier transform infrared spectroscopy as well as Raman spectroscopy confirmed the orthorhombic space group Pnma of the obtained materials. The calculated average grain size for powders is in the range of 30 to 80 nm. Magnetic characterization of the La(1-x)Gd(x)FeO3 series, performed at 1.72 K, indicated an antiferromagnetic state characterized by some canting of iron magnetic moments, in good agreement with the data reported for similar fine-particle systems.

Functional up-converting SrTiO3:Er(3+)/Yb(3+) nanoparticles: structural features, particle size, colour tuning and in vitro RBC cytotoxicity

SrTiO3 nanoparticles co-doped with a broad concentration range of Er(3+) and Yb(3+) ions were fabricated using the citric route as a function of annealing temperatures of 500-1000 °C. The effect of a broad co-dopant concentration range and sintering temperature on structural and up-conversion properties was investigated in detail by X-ray diffraction techniques and optical spectroscopy. The TEM technique was used to estimate the mean particle size, which was around 30 nm for the inorganic product annealed at 600 °C. Up-conversion emission color tuning was achieved by particle size control. Power dependence of the green and red emissions was found to be a result of temperature determination in the operating range of SrTiO3 nanoparticles and a candidate for the fast and local microscopic heating and heat release induced by IR irradiation. The color changed from white-red-yellow-green upon an increase of sintering temperature, inducing changes in the surface-to-volume ratio and the number of optically active ions in particle surface regions. The cytotoxic activity of nanoparticles on human red blood cells was investigated, showing no harmful effects up to a particle concentration of 0.1 mg ml(-1). The cytotoxic response of a colloidal suspension of nanoparticles to RBC cells was connected with the strong affinity of SrTiO3 particles to the cell membranes, blocking the transport of important biological solutes.

Multifunctional lanthanide and silver ion co-doped nano-chlorapatites with combined spectroscopic and antimicrobial properties

Nanocrystalline chlorapatites (Ca10(PO4)6Cl2) doped with lanthanide ions (Eu(3+), Er(3+) and Yb(3+)) and co-doped with silver ions (Ag(+)) were synthesized by a hydrothermal synthesis route. XRD, TEM, and SAED measurements indicated that the powders are single phased and crystallize with a hexagonal structure with good dispersion. The results showed well crystallized chlorapatite grains with a diameter of about 45 nm. The antimicrobial activity of the nanoparticles against Escherichia coli ATCC 11229 and ATCC 25922, Klebsiella pneumoniae ATCC 700603, and Pseudomonas aeruginosa PAO1 and ATCC 27853 was studied. The best activity was observed for the Eu(3+),Ag(+):Ca10(PO4)6Cl2 and Eu(3+),Ag(+),Yb(3+):Ca10(PO4)6Cl2 compositions. These multifunctional nanocrystalline powders could be used as a promising antimicrobial agent and material for bio-detection.

Up-conversion emission and in vitro cytotoxicity characterization of blue emitting, biocompatible SrTiO3 nanoparticles activated with Tm3+ and Yb3+ ions

Blue emitting, up-converting NP's of SrTiO₃:Tm³⁺/Yb³⁺ synthesized using the citric route are biocompatible towards J774.E whereas the cytotoxic effect to U2OS cells is not particle size dependent but most probably is related to Sr²⁺ ion release.

An up-converting HAP@β-TCP nanocomposite activated with Er3+/Yb3+ ion pairs for bio-related applications

A HAP@β-TCP nanocomposite doped with Er³⁺/Yb³⁺ ions was prepared and its cytotoxicity was tested on canine osteosarcoma and murine macrophage cells. Metronidazole release from the nanocomposite was studied and its up-conversion properties measured.

Preferential site substitution of Eu3+ ions in Ca10(PO4)6Cl2 nanoparticles obtained using a microwave stimulated wet chemistry technique

The Eu³⁺ doped Ca₁₀(PO₄)₆Cl₂ nanocrystalline powders were synthesized using a microwave stimulated technique. It is demonstrated that for low concentration Ca(ii) (A) site is preferentially substituted whereas increase of Eu³⁺ above 2 mol% results in domination of the Eu³⁺ cations located at Ca(i) (B) site.

Visualization of custom-tailored iron oxide nanoparticles chemistry, uptake, and toxicity

Nanoparticles of iron oxide generated by wearing of vehicles have been modelled with a tailored solution of size-uniform engineered magnetite particles produced by the Bradley reaction, a solvothermal metal-organic approach rendering hydrophilic particles. The latter does not bear any pronounced surface charge in analogy with that originating from anthropogenic sources in the environment. Physicochemical properties of the nanoparticles were thoroughly characterized by a wide range of methods, including XPD, TEM, SEM, DLS and spectroscopic techniques. The magnetite nanoparticles were found to be sensitive for transformation into maghemite under ambient conditions. This process was clearly revealed by Raman spectroscopy for high surface energy magnetite particles containing minor impurities of the hydromaghemite phase and was followed by quantitative measurements with EXAFS spectroscopy. In order to assess the toxicological effects of the produced nanoparticles in humans, with and without surface modification with ATP (a model of bio-corona formed in alveolar liquid), a pathway of potential uptake and clearance was modelled with a sequence of in vitro studies using A549 lung epithelial cells, lymphocyte 221-B cells, and 293T embryonal kidney cells, respectively. Raman microscopy unambiguously showed that magnetite nanoparticles are internalized within the A549 cells after 24 h co-incubation, and that the ATP ligand is retained on the nanoparticles throughout the uptake process. The toxicity of the nanoparticles was estimated using confocal fluorescence microscopy and indicated no principal difference for unmodified and modified particles, but revealed considerably different biochemical responses. The IL-8 cytokine response was found to be significantly lower for the magnetite nanoparticles compared to TiO(2), while an enhancement of ROS was observed, which was further increased for the ATP-modified nanoparticles, implicating involvement of the ATP signalling pathway in the epithelium.

Crystal structure and morphology evolution in the LaXO3, X = Al, Ga, In nano-oxide series. Consequences for the synthesis of luminescent phosphors

The LaXO(3):Tb(3+) (X = Al(3+), Ga(3+), In(3+)) perovskite nanoparticles were obtained using the nonhydrolytic treatment (Bradley reaction) of the molecular precursors of the La(O(i)Pr)(3), Al(O(i)Pr)(3), Ga(O(i)Pr)(3), In(5)O(O(i)Pr)(13), and Tb(acac)(3), respectively. It was shown that crystal structure and morphology evolution in the LaXO(3), X = Al, Ga, In nano-oxide series depended on the size and chemical properties of the X-metal atom. Formation of the LaInO(3):Tb(3+) nanoparticles is distinctly less thermodynamically demanding on contrary to the LaAlO(3):Tb(3+) and LaGaO(3):Tb(3+) since it provided crystalline product directly in the solution synthesis at 202 °C, which is the lowest reported synthesis temperature for this compound up-to-date. This behavior was ascribed to the effects directly connected with the dopant substitution (exchange of bigger La(3+) cation with smaller Tb(3+)) as well as reduction of the particle size. The size effects are mostly reflected in the expansion of the cell volume, changes of the cell parameters as well as shifting and broadening of the Raman bands. Indirectly, size reduction has also an effect on the luminescence properties through the higher probability of presence of surface and net defects as well as heterogeneous distribution of the Tb(3+) ions caused by high surface-to-volume ratio. The prepared nanophosphors show basically green emission with exception of white-green in case of the LaInO(3):Tb(3+). Strong emission quenching was found in the latter case being most likely a consequence of the nonradiative energy transfer between Tb(3+) and In(3+) as well as the presence of defects. In comparison to the Pechini's method, the LaXO(3) nanoparticles required significantly lower annealing temperature (700 °C) necessary for complete crystallization. Generally the resulting particles are distinctly smaller (5 to 25 nm) and less agglomerated (50-100 nm) depending on the reaction conditions as well as thermal treatment. For the first time, it was shown that the LaGaO(3):Tb(3+) nanopowder has crystallized in the high-temperature rhombohedral R3c phase.