Tissue and cellular localization of nanoparticles using 35S labeling and light microscopic autoradiography

Visualization of organic nanoparticles in cells and tissues, with their characteristics close to biomolecules, is particularly challenging. Formerly organic nanoparticles have been localized microscopically after the addition of fluorescent tags. However, the attachment of fluorochrome-molecules to these nanoscaled macromolecules may inevitably change physicochemical properties and subsequently alter their biological behavior in tissues. Here, we introduce a novel strategy for the localization of untagged organic dendritic polygycerol sulfate nanoparticles in mouse tissue. Based on radiolabeling the light microscopic autoradiography circumvents the drawbacks of fluorescent tagging and allows for a simultaneous light microscopical histopathology examination of the tissues for routine toxicology testing.263