Gold Nanoparticle as a Marker for Precise Localization of Nano-objects Within Intracellular Sub-domains

Delivery of nano-objects to certain intracellular sub-domains is crucial for nanomedicine. Therefore delivery of nano-object to desirable cellular compartment has to be confirmed. The most valuable confirmation of the delivery comes from direct visualization of the nano-object. This visualization usually requires use of microscope and corresponding probe which has to be conjugated with the nano-object. There are two most popular methods of the visualization: confocal and electron microscopy. The former has significant limitations due to diffraction limited resolution of confocal systems and three-dimensional convolution of fluorescence. The latter should be significantly modified for needs of the visualization. Here we describe the method for precise localization of nano-object within the cell using electron microscopy and 1–2 nm gold particles as a nanomarker.