Colour development of immunogold-labelled antibodies for light microscopy

Abstract

We describe an improvement of the immunogold technique, which is based on the colour development of silver-intensified immunogold signals. This method (referred to as the coloured-SIG technique) was found to be as sensitive as the silver-intensified immunogold method and more sensitive (in two of the three tested systems) than immunoenzymatic procedures, such as the peroxidase/antiperoxidase technique or the avidin-biotin system. The coloured SIG-method results in either a magenta-red or a cyan-blue final reaction product. Therefore, this new improvement of the immunogold technique should be useful in double-staining methods, immunoblot methods and conventional immunostaining methods.

Silver-Enhanced Colloidal Gold for Light Microscopy

“…Some chemical reactions used in color photography may be applied in a method analogous to that used in color autoradiography (Haase et al, 1985). Techniques resulting in either a magenta-red or a cyan-blue final reaction product have been proposed by Fritz et al (1986).…”

Improvements in the silver-staining technique for nucleolar organizer regions (AgNOR).

“…Several authors have proposed variations in the original procedure to reduce these problems, including: destaining of slides before silver staining (2); pre-or post-incubation of sections with alcoholic acetic acid (3,4,8,10,28), other acids (7,21), or glycine (7) to reduce background staining; variations in solution concentration (54); increase in pH (22); variations in temperature (3,4,7, 439 9,12,17); staining slides while inverted (4) or coating the sections with collodion ( 3 ) to reduce precipitates; conversion of the silver precipitate to a dye complex (12); combination with other staining procedures (18); replacement of the gelatin component with other colloids (26); and use of sodium thiosulfate (8,9,12) and gold toning (8,22) to improve permanence. None of these modifications has entirely controlled the problems.…”

Colloidal Gold for Multiple Staining

“…Recently, Fritz et al (1986) described the photochemical color develop ment of SIG, or "colored SIG" method; various dyes were used, giving a final reaction product magenta-red or cyan-blue. The technique was found to be as sensitive as the standard SIG method.…”

“…Colored SIG, using cyan-blue, was combined with an avidin-biotinperoxidase complex to visualize simultaneously two antigenic sites in human synovial tissue (Fritz et al, 1986). The peroxidase was revealed in red, using 3-amino-9-ethylcarbazole and H 2 0 2 .…”