Pierce Western Blotting Filter Papers, 2.5-mm thick, are pre-cut cotton sheets for wet or semi-dry, passive or electrophoretic transfer of proteins from polyacrylamide gels (SDS-PAGE) to PVDF, nitrocellulose, or other membranes. See all filter papers › Pierce Western Blotting Filter Papers are composed of high-quality alpha cotton cellulose fiber for use in northern, southern, and western blotting applications. These filter papers help to ensure quick and efficient transfer of molecules from gel to membrane. They are manufactured with ultrapure water without additives to minimize possible sources of background signal. They are suitable for use with alcohol or other organic solvents commonly used in protein and nucleic acid blotting applications.