1. Erase the phosphor-image screen.

2. Place the wrapped membrane next to the phosphorscreen screen (Molecular Dynamics). Note: Make sure to align the array with the grid on the phosphor-cassette.

3. Expose for 24-48 hrs.

4. Scan the exposed phosphor-image screen using the “STORM” scanner with a pixel size of 100 microns (10,000 dots/cm2). The resulting TIFF image files are then analyzed by pixel density using ImageQuant.