Prussian Blue staining of fluorescencing MLNP accumulations close to the intracerebroventricular injection site.

<p>(<b>A</b>) The magnetite in MLNPs shows emission in the green and red (insert) spectrum with blue and green excitation. It was imaged before doing the Prussian Blue staining from an untreated cryo-slice from PFA fixed brain. (<b>B</b>) shows the Prussian Blue staining, whereas blue color derives from the hexacyanoferrat complex. (<b>C</b>) is a maximum difference projection of (<b>A</b>) and (<b>B</b>), showing the overlap of MLNP fluorescence and Prussian Blue staining. (<b>D</b>) The fluorescence totally vanishes after Prussian Blue staining, indicating that binding the iron in the complex alters the excitability of the magnetite molecules. Abbreviations: F = fluorescence; LV = lateral ventricle; CC = corpus callosum. Magnification = 20x.