Observation of intracellular protein localization area in a single neuron using gold nanoparticles with a scanning...

The localization areas of intracellular proteins in rat cortical neurons were visualized using a scanning electron microscope (SEM) coupled with a focused ion beam (FIB) system. To obtain a clear contrast in the SEM images, gold nanoparticles (GNPs) were bound to specific intracellular proteins by antigen-antibody reactions. By obtaining a cross section of the desired location of the neurons by FIB milling under the SEM imaging condition, it was possible to observe the proteins inside the cells as clear bright spots. When a neuron was stained with anti-tau and anti-histone H1 antibodies, the bright spots were localized in the cross section of the axon and the nucleus, respectively. It was confirmed that targeted proteins in a single neuron on a substrate could be successfully identified. The development of FIB/SEM observation with immunological GNP staining will offer important information for the stable growth of neurons on various substrate structures, since the elongation and turning of axons on the substrates are activated by the redistribution of intracellular proteins.