N A N O P R O B E S     N E W S
Vol. 11, No. 4          April, 2011

for in situ hybridization
and immunohistochemistry:
Features and Advantages

Related Nanoprobes products:

Another great leap forward for in situ hybridization:

Buy onlineEnzMet™ is a biological labeling and staining method where a targeted enzymatic probe is used to selectively deposit metal at sites of interest.

EnzMet™ has proven to be very clean and sensitive both for in situ hybridization (ISH), where it readily visualizes both endogenous copies of single genes and allows the counting of copies of amplified genes, and immunohistochemistry (IHC) detection.

The sharply resolved black signal, used for in situ hybridization, is readily distinguished from other stains, and has been combined with fast red K immunohistochemistry to provide a concomitant brightfield gene and protein assay (EnzMet GenePro).


The mechanism of EnzMet SISH technology, with DAB comparison in HER2 breast cancer tissue assay.
(LEFT) The mechanism behind EnzMet™. (RIGHT) DAB vs. EnzMet: HER2 staining in HER2-amplified tissue (from a human breast cancer biopsy; courtesy of Dr. Raymond R. Tubbs, Cleveland Clinic Foundation).


The advantages of EnzMet include:

  • EnzMet™ technology uses horseradish peroxidase (HRP) to deposit metallic silver with extraordinary selectivity. Background is virtually zero.
  • Ultra high sensitivity: detect single copies of target genes, or low-abundance proteins, with almost no background.
  • Virtually no diffusion of reaction product means super-sharp signals with highest resolution. Individual gene copies are clearly differentiated.
  • Black, sharply defined, non-diffusing stain lets you clearly see underlying morphology.
  • EnzMet™ is readily distinguished from most counterstains.
  • Does not fade or bleach: specimens stained with EnzMet™ can be archived indefinitely.


EnzMet™ available for both manual staining
and automated commercial use

For manual in situ hybridization and immunohistochemical staining, you can purchase the EnzMet™ HRP Detection Kit for IHC / ISH directly from Nanoprobes.

Nanoprobes has also licensed EnzMet™ to Ventana Medical Systems (now a part of the Roche Group) for the commercial use of this reagent in automated slide staining instruments and applications.

As a result, the first commercial product has now been introduced in Europe, Australia, Japan and other parts of the world; it is called SISH (Silver In Situ Hybridization). Introduction of SISH in the United States is pending FDA approval.



Powell, R. D.; Pettay, J. D.; Powell, W. C.; Roche, P. C.; Grogan, T. M.; Hainfeld, J. F., and Tubbs, R. R.: Metallographic in situ hybridization. Hum. Pathol., 38, 1145-1159 (2007).

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