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The method of magnetic particle imaging (MPI) is substantially limited by a rather small field of view (FOV) even in preclinical imaging. To cover a bigger FOV, a multi-patch approach – i.e., scanning of a series of small FOVs (patches) shifted in the space - is necessary. Here, we present a simple software tool for merging of patches into a final 3D volume data of the scanned object. The software reads reconstructed data produced by a field-free point scanner (MPI 25/20FF, Bruker BioSpin MRI GmbH, Germany), merges them, averages data overlapped in the space, and export them in DICOM format. The software is free for non-commercial use., International Journal on Magnetic Particle Imaging IJMPI, Vol 9 No 1 Suppl 1 (2023)

Multimodal imaging, integrating several modalities including down- and up-conversion luminescence, T1- and T2(T2*)-weighted MRI, and CT contrasting in one system, is very promising for improved diagnosis of severe medical disorders. To reach the goal, it is necessary to develop suitable nanoparticles that are highly colloidally stable in biologically relevant media. Here, hydrophilic poly(N,N-dimethylacrylamide-N-acryloylglycine methyl ester)-alendronate-[P(DMA-AGME)-Ale]-coated Gd(Tb)F3:Tb3+(Gd3+),Yb3+,Nd3+ nanoparticles were synthesized by a coprecipitation method in ethylene glycol (EG) followed by coating with the polymer. The particles were tho-roughly characterized by a dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray energy dispersive spectroscopy (EDAX), selected area electron diffraction (SAED), elemental ana-lysis and fluorescence spectroscopy. Aqueous particle dispersions exhibited excellent colloidal stability in water and physiological buffers. In vitro toxicity assessments suggested no or only mild toxicity of the surface-engineered Gd(Tb)F3:Tb3+(Gd3+),Yb3+,Nd3+ particles in a wide range of concentrations. Internalization of the particles by several types of cells, including HeLa, HF, HepG2, and INS, was confirmed by a down- and up-conversion confocal microscopy. Newly developed particles thus proved to be an efficient contrast agent for fluorescence imaging, T1- and T2(T2*)-weighted magnetic resonance imaging (MRI), and computed tomography (CT).

A modified procedure for preparation of iron oxide nanoparticles was used to produce nanoparticles suitable for magnetic particle imaging (MPI). Cationic and anionic maghemite particles were prepared and coated by poly(N-(2-hydroxypropyl)methacrylamide)-co-N-[2-(hydroxyamino)-2-oxo-ethyl]-2-methyl-prop-2-enamide. Bare and coated particles were characterized by magnetometry, dynamic light scattering, MR relaxometry, transmission electron microscopy and tested in vitro in a field-free-point MPI scanner. The nanoparticles were compared to Resovist and to differently oxidized particles dedicated for magnetic resonance imaging (control NP). The cores of particles had an average diameter 8.0 nm (cationic ones) and 8.7 nm (anionic ones), hydrodynamic diameter of coated particles in water colloids was 88 nm, and zeta potential +52 mV or –60 mV for cationic or anionic particles respectively).Cationic particles provided at MPI lower signal-to-noise ratio than Resovist, while anionic higher by 25%. Also signal dispersion to surrounding voxel was smaller. The worst results were reached in the case of control NP. Int. J. Mag. Part. Imag. 6(2), Suppl. 1, 2020, Article ID: 2009019, DOI: 10.18416/IJMPI.2020.2009019, International Journal on Magnetic Particle Imaging, Vol 6 No 2 Suppl. 1 (2020)

Nanomateriály jsou v současnosti předmětem intenzivního výzkumu díky jejich možnému využití na poli biomedicíny, optiky a elektroniky. Připravili jsme a testovali nanočástice na bázi feritů s kobaltem a zinkem (Co0.5Zn0.5Fe2O4+γ [CZF-NPs]) obalované amorfní silikou, které by měly sloužit jako kontrastní látka pro sledování transplantovaných buněk v organismu pomocí magnetické rezonance (MRI). Potkaní mesenchymální buňky (rMSC) byly inkubovány 48 h s nízkou, střední nebo vysokou koncentrací (0,05, 0,11 nebo 0,55 mmol) nanočástic nebo se silikou (Si-NPs, 0,11 mmol) sloužící jako negativní kontrola. Internalizace nanočástic byla potvrzena pomocí elektronové transmisní mikroskopie. Biologické účinky byly hodnoceny ihned po expozici a po dalších 72 h v čerstvém médiu bez nanočástic. Pomocí značení annexinem V/PI nebyl odhalen žádný rozdíl v cytotoxicitě (v úmrtnosti buněk, pozn. překl.) mezi jednotlivými skupinami buněk, pouze nejvyšší koncentrace nanočástic snížila přírůstek buněk a zvýšila poškození DNA, které se projevilo jako vyšší počet zlomů a oxidovaných bází. U těchto buněk bylo nalezeno také zvýšení koncentrace 15-F2t-isoprostanu a karbonylových skupin, což svědčilo pro oxidativní poškození u tohoto vzorku. Žádné poškození (makromolekul) nebylo pozorováno u nízké koncentrace nanočástic. I buňky inkubované s touto nejnižší koncentrací nanočástic prokázaly dostatečné relaxační časy v opakovaných MRI experimentech a ICP-MS potvrdila dostatečné množství nanočástic uvnitř buněk. Tyto výsledky podporují možné využití silikou obalovaných CZF-NPs v nízkých netoxických koncentracích jako intracelulární kontrastní látky pro MRI. Nanomaterials are currently the subject of intense research due to their wide variety of potential applications in the biomedical, optical and electronic fields. We prepared and tested cobalt zinc ferrite nanoparticles (Co0.5Zn0.5Fe2O4+γ [CZF-NPs]) encapsulated by amorphous silica in order to find a safe contrast agent and magnetic label for tracking transplanted cells within an organism using magnetic resonance imaging (MRI). Rat mesenchymal stem cells (rMSCs) were labeled for 48 h with a low, medium or high dose of CZF-NPs (0.05; 0.11 or 0.55 mM); silica NPs (Si-NPs; 0.11 mM) served as a positive control. The internalization of NPs into cells was verified by transmission electron microscopy. Biological effects were analyzed at the end of exposure and after an additional 72 h of cell growth without NPs. Compared to untreated cells, Annexin V/Propidium Iodide labeling revealed no significant cytotoxicity for any group of treated cells and only a high dose of CZF-NPs slowed down cell proliferation and induced DNA damage, manifested as a significant increase of DNA-strand breaks and oxidized DNA bases. This was accompanied by high concentrations of 15- F2t-isoprostane and carbonyl groups, demonstrating oxidative injury to lipids and proteins, respectively. No harmful effects were detected in cells exposed to the low dose of CZF-NPs. Nevertheless, the labeled cells still exhibited an adequate relaxation rate for MRI in repeated experiments and ICP-MS confirmed sufficient magnetic label concentrations inside the cells. The results suggest that the silica-coated CZF-NPs, when applied at a non-toxic dose, represent a promising contrast agent for cell labeling.