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

Catecholamines play a crucial role in signal transduction and are also expected to act as endogeneous antioxidants, but the mechanism of their antioxidant action is not fully understood. Here, we describe the impact of pH on the kinetics of reaction of four catecholamines (L-DOPA, dopamine, adrenaline, and noradrenaline) with model 2,2-diphenyl-1-picrylhydrazyl radical (dpph^•) in methanol/water. The increase in pH from 5.5 to 7.4 is followed by a 2 order of magnitude increase in the rate constant, e.g., for dopamine (DA) k^pH5.5 = 1,200 M^–1 s^–1 versus k^pH7.4 = 170,000 M^–1 s^–1, and such rate acceleration is attributed to a fast electron transfer from the DA anion to dpph^•. We also proved that at pH 7.0 DA breaks the peroxidation chain of methyl linoleate in liposomes assembled from neutral and negatively charged phospholipids. In contrast to no inhibitory effect during peroxidation in non-ionic emulsions, in bilayers one molecule of DA traps approximately four peroxyl radicals, with a rate constant k_inh >10³ M^–1 s^–1. Our results from a homogeneous system and bilayers prove that catecholamines act as effective, radical trapping antioxidants with activity depending on the ionization status of the catechol moiety, as well as microenvironment: organization of the lipid system (emulsions vs bilayers) and interactions of catecholamines with the biomembrane.

Upconverting/paramagnetic Gd₂O₃:1% Er³⁺, 18% Yb³⁺with Zn²⁺nanoparticles (NPs) permits one to perform optical imaging.

Efficiently upconverting, spherical ZnAl ₂ O ₄ nanoparticles (NPs), doped with erbium and ytterbium, were synthesized by a combustion aerosol method (CAM) and transported to cytosol of carcinoma cell line (HeLa) for the first time.

We demonstrate structural and room temperature magnetic properties of Fe doped ZnO nanofibers (NFs) obtained by electrospinning followed by calcination. The observed NFs, formed from crystalographically oriented, approximately 4.5 nm particles conglomerates, were approximately 200 nm in diameter. The reported synthesis of room temperature ferromagnetic Fe doped ZnO NFs is both facile and economical, and is therefore suggested as a generic method of fabricating biocompatible magnetic materials. The major substrates selected for the NFs synthesis (Zn, Fe) comprised of relatively low toxicity materials. Incorporating 10% Fe into ZnO does not modify the wurtzite crystal structure of the host material. No evidence of impurity phase was detected by either X-ray or electron diffraction. Magnetometry studies and Magnetic Force Microscopy imaging reveal a local ferromagnetic order that persists up to room temperature. We suggest that the observed phenomenon is either due to a mechanism mediated by presence of oxygen vacancies and/or is related to iron-rich precipitates.

Multicolor upconversion of SiO₂-coated nanoparticles using for cells imaging and reactive oxygen species generation.