WesternBright ChemiPen

Transform your protein standard into a chemiluminescent marker!


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Write or draw on your transfer membranes with the WesternBright ChemiPen. With the proprietary “ink” you can make pre-stained protein standards chemiluminescent, annotate your blot with a date or blot number, or check the quality of your HRP substrates. The reagent in the ChemiPen adsorbs to nitrocellulose and PVDF membranes, and reacts with HRP substrates to produce chemiluminescence that can be detected with X-ray film or CCD imaging..



  • Improve accuracy – transform your visible protein ladder standard into a chemiluminescent standard on your Western blot
  • Annotate – permanently mark your blots with the date or blot ID
  • Confirm HRP substrate stability – the ChemiPen reagent glows when incubated with an HRP substrate, so it can be used to test substrate stability
  • Compatible – with both X-ray film and CCD imagers


With the WesternBright ChemiPen, you can write or draw on your Western blot membranes with an “ink” that will produce light after incubation with HRP substrates.
You can use the WesternBright ChemiPen to transform your visible protein markers into chemiluminescent markers, to annotate your blot with a date or blot ID, or to check the stability of your HRP substrate (Figure 1).

ChemiPen Figure 1
Figure 1. The WesternBright ChemiPen can be used to mark the location of protein standards and to annotate the blot with a date, as in the right panel.

Marking the location of visible protein standards on a blot is easy. Simply trace the visible markers on the membrane after transfer and before blocking (Figure 2).

ChemiPen Figure 2
Figure 2. Use the WesternBright ChemiPen to visualize visible protein standards on chemiluminescent Western blots

The WesternBright ChemiPen has two tips, a fine tip at one end that is perfect for writing on the blot or tracing the bands of a visible protein standard, and a thicker wedge tip that can be used to deposit greater amounts of reagent on the blot.


PChemiPen Flyer

ChemiPen UserManual

WB Guide


For the inhibition of protease activity, it is suggested to use 10 µl of GRS Protease Inhibitor Cocktail for each 1ml of cell lysate prepared from a cell culture with a density of 108cells/ml. Yet, as levels of endogenous proteases vary a lot between different organisms/cells, it is recommended to optimize final concentration for a particular experiment.

Order Information

R-07055-001 ChemiPen 1 each