Intended use:

The Aqua-Hold pap pen is a special marking pen that provides a thin film-like barrier when a circle is drawn around the specimen. This barrier creates the proper surface tension to hold antibody solution within the target area on the slide. Aqua-Hold is very effective for Immunostaining procedures by the Peroxidase-Antiperoxidase (PAP) method, ABC method, B-SA method, immunofluorescence method, ASD method, Enzyme method and Frozen Section method. The surface tension provided by the barrier ensures that only a small amount of antibody solution is needed. Two specimens, separated by two circles, can be applied to the same slide. The pen contains a special formulation that is water repellent and stable for long time period. It can be removed, if desired, by xylene after the staining procedure is completed.

Instructions for use:

To start use of pen, take off cover and press felt tip down on a glass slide several times on a flat surface until a flow of material is seen. It might be heavy in flow. If so, wait until the felt tip is fully saturated with film material (turns a darker brown) and wipe off the excess with paper towel. The Aqua-Hold is now primed and can be used to draw the desired barrier on the slide.

For Paraffin sections:

Deparaffinize and rehydrate the section according to accepted procedures. For proper adhesion of the barrier circle, the glass slide surface should be clean and dry. Remove the slide from water or buffer solution; dry around tissue section with water absorbent paper; encircle the section with the pen. Allow the circle to dry for approximately 1 minute at room temperature and return the slide to water or buffer. If trypsinization or another proteolytic digestion is to be used, apply the film barrier after that step is completed.

For Frozen Section:

The film circle may be applied on the glass surface (at room temperature) either before fixation or prior to the first immersion in the water or buffer. If the slide is treated with hydrophile, soak the slide in 0.1N hydrochloric acid for 30 seconds. Wash it with water and dry. This will help prevent the film guard from lifting.


The solvent is flammable and possibly toxic. Use the pen in a well ventilated area. The Aqua-Hold pen may need further priming after sitting without use. Refer to instructions for use above to continue using the pen.