ImmEdge® Hydrophobic Barrier PAP Pen

SKU Unit Size Price Qty
H-4000 2 pens
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The ImmEdge Pen (H-4000) represents an improvement over the PAP pen for immunohistochemistry, immunocytochemistry, immunofluorescence, and in situ hybridization. It is designed to provide a heat-stable, water-repellent barrier that keeps reagents localized on tissue specimens and prevents mixing of reagents when multiple sections are mounted on the same slide.

The barrel of the ImmEdge Pen is composed of acetal plastic which allows for consistent tip retention, easier tip saturation, and improved fluid flow.

ImmEdge Pen Features:

  • Light blue barrier
  • Compatibility with enzyme or fluorescence-based detection systems
  • Solubility in all commonly used clearing agents 


More Information
Unit Size 2 pens
Applications Immunohistochemistry / Immunocytochemistry, Immunofluorescence, In situ hybridization
Safety Title WARNING: Cancer and Reproductive Harm -


Product FAQs

What is the capacity of the ImmEdge Hydrophobic Barrier PAP Pen (H-4000)?

The volume of the ImmEdge Pen (H-4000) is about 6 mL. We have not characterized how many times it can be used or overall length of the barrier due to variability in its application.

What is the width of the nib/tip supplied with the ImmEdge pens?

The nib provided with each ImmEdge Pen is 3 mm wide.

Can I apply the ImmEdge Pen residue to wet slides?

Yes. The ImmEdge Pen residue contains a wax constituent that allows for application to microscope slides that have buffer or similar aqueous solutions on the surface. Applying the pen residue to wet slides does not affect adhesion of the residue nor interfere with the tissue section.

Does the ImmEdge Pen residue fluoresce?

Yes, the pen residue does fluoresce. However, this property does not limit the pens use to only light microscope applications. We routinely use the ImmEdge pen for immunofluorescent tissue staining applications. Usually the pen residue is applied well outside of the tissue section perimeter, and as such, the inherent fluorescent properties of the pen residue do not interfere with specific fluorescent signal.

I just received an ImmEdge Pen and when I took the cap off the nib fell out. Is the pen still functional?

Yes. The pen design ensures the nib can move and that the nib is not adhered to the pen itself. The nib needs to move so that once received the nib can be depressed to break the internal membrane to allow residue to flood the nib. In some instances, during shipping, the nib may become dislodged and fall out. Simply put the nib back into the neck of the pen and use as per the supplied instructions. Once the residue floods the nib, the nib material expands slightly to hold the nib within the pen neck.

How long do I leave the pen residue to dry on the slides before proceeding with the rest of the staining procedure?

The pen residue does contain a solvent that dries within seconds of being placed onto the slide. There is no requirement to wait for the residue to dry. In essence the residue dries the moment it is applied.


Technical Information

The ImmEdge Pen barrier is stable for use with buffers with and without detergent (e.g. Tween 20 or Triton X-100, etc.). The pale blue barrier is insoluble in alcohol and acetone, but is completely removed by all commonly used xylene and xylene substitute clearing agents. The barrel of the ImmEdge Pen is composed of acetal plastic which allows for consistent tip retention, easier tip saturation, and improved fluid flow.

For more product information, read this product review on

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