nCircle What Matters – IHC Specimens!

Immunohistochemistry, immunocytochemistry, immunofluorescence, and in situ hybridization require analysis of specimens / cells / tissues on slides after reagent treatment. This analysis is done mostly by viewing through a microscope. 

However, often when you place a specimen on a slide to place it under a microscope, the specimen may face a reagent wipeout. Alternatively, when performing differential staining, it may also mix and interfere with the staining samples and thereby give inaccurate results.

Hence, a Hydrophobic Slide Marker or a PAP Pen is used to draw a water-repellant mark in any shape around a specimen on a slide in immunohistochemistry, immunocytochemistry, immunofluorescence, and in situ hybridization. Generally a circle, the shape can be a square, a triangle, a polygon or any closed shape for that matter. This is done to keep solutions close to the sections once the permeabilization step has been carried out. A hydrophobic slide marker or a pap pen’s use is not entirely essential, but it is highly recommended. 

A good hydrophobic slide marker allows to confine the flow of reagents to a defined area by the pen. During staining procedures, this helps to avoid repeated wipeout around the specimen.

At the same time, it will also help to prevent mixing of reagents when performing differential staining and conserve precious antibodies and reagents. Generally such a marker is soluble in all commonly used clearing agents like Xylene, but insoluble in alcohol. A good hydrophobic slide marker will also be non-eroded by Triton X-100 or Tween20. 

For immunohistochemistry, the hydrophobic slide marker should ideally be applied after deparaffinization.

Features of a good hydrophobic slide marker:

• Hydrophobic & high heat-resistant
• Confinement of flow of reagents to defined area
• Prevention of reagent mixing when performing differential staining
• Uniform spreading of reagents on slides
• Conservation of precious antibodies & reagents
• Saving cost per slide
• Repeatability & reproducibility
• Soluble in all commonly used clearing agents 

The downfall of most readily available hydrophobic slide markers or pap pen in the market is its toxicity. Along with causing skin & eye irritation, prolonged usage can cause respiratory irritation, drowsiness, dizziness, damage fertility or unborn foetus, damage organs (CNS & liver).  etc. It may also be carcinogenic or cause genetic defects. It may also be harmful to aquatic life with long lasting effects. 

One can never be too careful when using such a product. 

Afterall, setting boundaries – on a slide & in life, is our responsibility!

So is there a solution out there which gives all the benefits required but avoids the pitfalls of the ones commercially prevalent in the market?

DSS brings an indigenously developed unique non-toxic water repellant slide marker, which does away with all the health risks associated with the regular Pap Pens available in the market – the nCircle Hydrophobic Slide Marker from NeoDx Biotech Labs Pvt. Ltd.!