Fig. 5

Distribution of MDA-MB-231 cells labeled with BSA-NWs after implantation in mouse brain at 11.7 T. Minimal intensity projections of all brain transverse 2D slices of the 3D image sets where BSA-NW labeled cells were present. Circa 10 cells were implanted on the left hemisphere (left side of the images), while circa 100 cells were implanted in the right hemisphere (right side of the images). Images were acquired immediately after implantation (a), and at days 10 (b), 20 (c), and 40 (d) post-implantation in living mouse. White arrows indicate the distribution of implanted cells along the injection needle tracks and into the corpus callosum. Correlation of mouse brain MRI images of implanted NW-labeled cells and optical images of histological slices of the same brain region stained with Perls’ Prussian blue for Fe detection 40 days post-implantation. Magnification of the left (e) and right (f) hemispheres showing MRI images (I), optical microscopy images of histological preparations (II), and overlay of both imaging methods (III). Perls’ Prussian blue stains NWs in blue due to the presence of Fe³⁺ in the oxide shell