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.

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.

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

An effective, simple and practically useful method to incorporate fluorescent nanoparticles inside live biological cells was developed. The internalization time and concentration dependence of a frequently used liposomal transfection factor (Lipofectamine 2000) was studied. A user friendly, one-step technique to obtain water and organic solvent soluble Er(3+) and Yb(3+) doped NaYF4 nanoparticles coated with polyvinylpyrrolidone was obtained. Structural analysis of the nanoparticles confirmed the formation of nanocrystals of the desired sizes and spectral properties. The internalization of NaYF4 nanoparticles in HeLa cervical cancer cells was determined at different nanoparticle concentrations and for incubation periods from 3 to 24 h. The images revealed a redistribution of nanoparticles inside the cell, which increases with incubation time and concentration levels, and depends on the presence of the transfection factor. The study identifies, for the first time, factors responsible for an effective endocytosis of the up-converting nanoparticles to HeLa cells. Thus, the method could be applied to investigate a wide range of future 'smart' theranostic agents. Nanoparticles incorporated into the liposomes appear to be very promising fluorescent probes for imaging real-time cellular dynamics.