EnzMet™ is our metallographic peroxidase substrate. Use it in place of DAB or other organic chromogens for Western blotting, in situ hybridization (ISH), immunohistochemistry (IHC), electron microscopy, correlative microscopy, nanowires and biochips
Updated: May 16, 2024
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HER2 staining in HER2-amplified tissue from a human breast cancer biopsy. Dr. Raymond R. Tubbs, Cleveland Clinic.
What is EnzMet?
Clearer, crisp staining for Western blotting, in situ hybridization (ISH), and immunohistochemistry (IHC)
EnzMet (Enzyme Metallography) is a new biological labeling and staining method developed at Nanoprobes. It uses a targeted enzymatic probe with a novel metallographic substrate to provide a quantum leap in staining clarity over conventional chromogenic and fluorescent substrates.
EnzMet™ has proven highly sensitive both for in situ hybridization (ISH), where it readily visualizes endogenous copies of single genes, and immunohistochemistry (IHC) detection.
It has also been used as an electrical detection method and to create nanowires for biochips.
Comparison of EnzMet with conventional DAB immunohistochemistry and enhanced DAB, showing superior contrast and sensitivity even without further amplification. Cytokeratins in paraffin-embedded bladder tumor stained with monoclonal primary antibody (AE1/AE3, Dako) and peroxidase secondary (Envision, Dako).
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Features of EnzMet
Patented EnzMet technology uses HRP to deposit metallic silver with extraordinary selectivity.
High sensitivity: detect single copies of target genes, or low-abundance proteins with virtually no background.
Compatible with all counterstains: lets you clearly see surrounding tissue morphology (as opposed to fluorescent signals where surrounding tissue is not visible)
Minimal diffusion: super-high resolution compared with DAB.
Near zero background.
Does not fade or bleach.
The sharply resolved black signal is readily distinguished from other stains: it has been combined with fast red K immunohistochemistry to provide a concomitant brightfield gene and protein assay.
EnzMet has many advantages both over fluorescent labels and enzyme chromogens. Because it is used in the conventional brightfield microscope, it does not require fluorescent optics, or dark adaptation on the part of the user. The signal is permanent, and does not have the photobleaching problems associated with fluorescent stains.
EnzMet™'s high density enables visualization at even low magnification. It produces a sharp metal deposit that does not diffuse like DAB, giving higher resolution localizations. Because the deposited metal is electron-dense, it provides high contrast for electron microscopy, making enzyme metallography a potential correlative light and electron microscopy method.
Featured Applications:
Western blotting: quick, sensitive and reliable with EnzMet™
The EnzMet™ Western Blot HRP Detection Kit (Catalog #6002) uses horseradish peroxidase (HRP) - catalyzed silver deposition at the precise location of the enzyme for specific HRP detection on Western blots and in dot blotting applications. EnzMet™ silver deposition results in dense, highly discrete, sharp-edged, permanent black bands and dots ideal for direct visualization, imaging and archiving.
Comparison of HRP detection with EnzMet™ vs. DAB and Metal-enhanced DAB Substrate Kit:
6xHis-tagged recombinant Src protein (Millipore # 14-326), probed using anti-His·Tag® mouse monoclonal antibody (Millipore # 70796-3) followed by goat anti-mouse IgG HRP conjugate (Millipore # 71045), then detected by:
(left) DAB Substrate Kit,(center) metal-enhanced DAB Substrate Kit, and (right) EnzMet™ Western Blot HRP Detection Kit.
Better than DAB: EnzMet™ replaces DAB or any other peroxidase-activated chromogen or fluorogenic substrate to provide sharp, clear, permanent results.
Nanoprobes recently teamed with Ventana Medical Systems to create a definitive HER-2 breast cancer test based on EnzMet, using SISH (Silver In Situ Hybridization). Treatment for this disease was already quite effective, but a good test for it remained the missing link between detection and cure. The test is now being used across the United States and Europe, and Nanoprobes is very proud to be have been a part of this effort.
Human breast cancer biopsy tissue section where single copies (2 per normal cell) of the Her 2/neu gene were detected by EnzMet (black spots).
Better than FISH: EnzMet enables bright field detection, a permanent signal, and use of full-strength H&E staining for simultaneous visualization of underlying tissue morphology.
Original magnification x 400; courtesy of Dr. Raymond R. Tubbs, Cleveland Clinic Foundation.
HER2 staining [Feature article]
Simultaneous ISH/IHC assay for HER2 gene amplification and concomitant oncoprotein overexpression (using Fast Red K IHC with EnzMet ISH).4
At right:
HER2 staining in HER2-amplified tissue,
from a human breast cancer biopsy.
Courtesy of Dr. Raymond R. Tubbs,
Cleveland Clinic Foundation.
DAB
EnzMet
Immunodot and Protein Blots
Highly sensitive visualization on immunodot blots and other protein blots with negligible background.
Biochip Fabrication [Feature article]
Highly specific electrical detection using conductive array biochips:
enzyme-labeled DNA probes were developed with EnzMet to form conductive bridges.5
Electrical detection system: target oligonucleotide is deposited between electrodes, detected with enzymatic probe and "developed" with enzyme metallography to form a conductive connection.5
Custom conjugation is also available, of Nanogold®, FluoroNanogold, undecagold
or colloidal gold to primary antibodies, peptides, small molecules, or other molecules.
* Not formulated or approved for clinical use or use in automated slide stainers. Contact Ventana Medical Systems for all automated and clinical applications.
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