Silver enhancement has long been used by microscopists to better visualize gold labeling, especially when using small gold particles. With GoldEnhance™, gold ions are specifically deposited around the gold nanoparticle, growing it in size, and offering several advantages over silver.

For TEM, the 1.4 nm Nanogold® can be enlarged to 3-20 nm for clear visiblility, even at low magnifications. Using an initial small gold immunoprobe allows better penetration into tissues (up to 40 microns!) and better labeling of antigens. Then gold enhancement makes everything clearly visible.

The development time can be extended to deposit more gold and make the signal visible by bright field (or reflection) light microscopy. With a little more development time, the signal can be seen by the naked eye, and can be used with dot blots or Westerns.

Why GOLD?

Advantages over silver:

• May safely be used before osmium tetroxide staining (silver is dissolved by the oxidizing agent O₄; gold is stable)
• Lower backgrounds than silver in many cases; autonucleation minimal even after 1-2 hours
• For SEM, gold gives a much better backscatter signal than silver
• Compatible with physiological buffers (silver precipitates with chloride ion, as in PBS buffer; gold does not)
• Reaction is less pH senstitive than silver, and GoldEnhance™ is near neutral for best structural preservation of biological samples (many silver enhancers have a pH of 3-4)
• Excellent shelf life
• Low viscosity for easy and accurate mixing of components