Magnetic resonance imaging of mesenchymal stromal cells labeled with uncoated multidomain iron oxide nanoparticles

Abstract

Background & Aim The development of regenerative therapy makes necessary the creation of a method for in vivo labeling of cells for subsequent in vivo imaging. In case of large organisms such as humans, magnetic resonance imaging (MRI) seems to be the optimal visualisation technique. Single domain (i.e. with the size The aim of the work was to evaluate the possibility of using uncoated iron (II, III) oxide nanoparticles obtained by wire explosion in an air atmosphere to obtain labeled mesenchymal stromal cells (MSC) for subsequent visualization by MRI in tissues using clinical 1.5T MRI scanners. Methods, Results & Conclusion The viability, trilineage differentiation potential, immunophenotype were evaluated with flow cytometry. The size of the particles was measured with the DLS and electron microscopy methods. The colocalisation of IONP with lysosomes, autophagosomes and endosomes was studied with immunochemistry methods.The imaging of labeled cells injected post mortem into the bovine liver was performed with Siemens Espree and PHILIPS Ingenia 1,5T MRI scanners. MSC internalise IONP without reducing proliferative activity, viability, and changing the set of surface markers. IONP obtained by the method of explosion had a shape close to spherical. Particle size varied from 14 to 136 nm with IONP up to 136 nm composing 75% of particles, and IONP less than 36 nm - 10%. All IONP were localised in late endosomes and autophagosomes in 10 h of incubation with IONP being thus covered with a membrane. A wide range of particle sizes made it possible to select imaging parameters during MRI in animal tissues both in the T2 mode and in the T1 relaxation mode because of combination of IONP with ferro- and superparamagnetic properties. We conclude that IONP obtained with dry wire explosion can be used for MSC labelling in vivo for subsequent MRI imaging.