Once tissues are fixed and permeabilized, the antibodies are added. These antibodies can be labeled directly or detected by a labeled secondary reagent. For indirect detection, any reagent that binds specifically to the primary antibody can be "tagged" and used to locate the antibody. The possible reagents include anti-immunoglobulin antibodies, protein A or G, or, if the first antibody is labeled with biotin, streptavidin. They can be labeled with enzymes or gold. - [Read Binding Antibodies to Tissue Sections Protocol]
The technique has many advantages—plasmids may be used for delivery, DNA theoretically can be delivered to any cell type, and genes may be delivered to cells in vitro, ex vivo, or in vivo. DNA-coated gold particles are distributed evenly along the length of the tubing, which is subsequently cut into short sections of cartridges to be used in a gene gun. The Helios Gene Gun uses a pulse of helium to launch the DNA-coated particles, spreading them onto the target cells. - [Read Gene Delivery to Skin Using Biolistics Protocol]
In brief, the reaction mixture, is prepared in exactly the same way as if the sample is to be stained or shadowed for electron microscopy, but once the... Gold labeling technique for electron microscopic identification and location of proteins. - [Read Gold labeling of proteins for electron microscopy]
This protocol provides a description of how to introduce double-stranded RNA (dsRNA) into Drosophila embryos by microinjection. Several days of preparation are required before injections into Drosophila embryos begin. Flies must be in abundant supply for egg collection. Bombardment of embryos with dsRNA-coated gold particles (Delivery of dsRNA into Drosophila Embryos by a Gene Gun) can be used as an alternative. - [Read Microinjection of dsRNA into Drosophila Embryos Protocol]
Protargol-S (silver proteinate) is used with the addition of copper metal. The copper replaces the silver in the connective tissue, allowing a greater differentiation between the nerve fibers and the connective tissue. The silver is reduced with hydroquinone to the visible metallic form. The sections are toned with gold chloride, the gold chloride is reduced with oxalic acid, increasing the deposit of metallic gold on the sections. - [Read Staining of Nerve Fibers Protocol]