Disodium Hydrogen Phosphate Facilitates the Gold Enhancement Reaction of Nanogold in the Pre-embedding Immunoelectron Microscopy

Immunoelectron microscopy is a technique for analyzing molecular localization at the ultrastructural level. In the pre-embedding immunoelectron microscopy, samples are immunolabeled with extremely small gold particles. Gold enhancement then enlarges the gold particles to an easily visible size. During the examination of the optimal conditions, we found that phosphate buffer accelerates the enhancement reaction. Furthermore, disodium hydrogen phosphate was identified as responsible for this effect. Disodium hydrogen phosphate enabled the gold labeling of deep regions within thick tissue samples. In conclusion, our method is useful for increasing the sensitivity, especially in the deeper region of the sample.