A simple enhancement method for the silver-gold-intensified diaminobenzidine reaction in the light microscopic immunoperoxidase technique.

We describe a simple and sensitive method for enhancement of the silver-gold-intensified 3,3'-diaminobenzidine (DAB) reaction demonstrating peroxidase activity. After completing silver-gold intensification of the preparations immunostained by the avidin-biotin-peroxidase method with DAB as the chromogen, the preparations were immersed in a solution containing uranyl nitrate. This new method appeared to increase the sensitivity by at least one order of magnitude as compared with silver-gold intensification alone.