DAB metal enhancer is used to enhance the signal strength in peroxidase (HRP) detections and to modify the signal colour from brown to purplish gray. Applications include all immunochemical assays like immunohistochemistry and -cytochemistry as well as Western blotting, but DAB metal enhancer may also well be used during in situ hybridization. DAB Metal Enhancer ready-to-use, for immunochemistry Mechanism When the DAB metal enhancer is applied, the sensitivity of DAB staining is about two times higher than with DAB alone. Figure: Immunohistochemical staining of mouse small intestines with an anti-PCNA antibody. Minuscules: pure DAB substrate, capitals: detection supplemented by DAB enhancer (A: NiCl 2 , B: DAB Metal Enhancer, Art. No. 9204). A/a: Basic method using 0.6 mg/ml DAB in Tris-buffer. B/b: Detection performed with the ROTI ® DAB Kit. Directions for use For application, the DAB substrate components and buffer reagents (for instance ROTI ® DAB-Kit, Art. No. 9202) are simply diluted in DAB metal enhancer instead of water. The purplish gray precipitate resulting from the staining reaction can be detected in visible light and does not bleach during long-term storage. Since it is insoluble in aqueous and organic solvents, slides may be permanently mounted in hydrophilic, or, after dehydration, in hydrophobic mounting medium. Figure 1: Dot blot of a HRP conjugated antibody (400, 200, 100, 50 and 25 pg). CR/cr: Detection using ROTI ® DAB Kit A-e: Detection using kits and DAB substrates from other suppliers CR: Detection under supplementation with DAB Metal Enhancer A: Detection under supplementation with NiCl 2