N NAE-Methylenebisacrylamide is commonly called as bis. It is used as a cross-linking agent in the preparation of polyacrylamide gels consisting of chains of acrylamide monomers. The concentration of N NAE-methylenebisacrylamide and acrylamide determines the pore size of the gel. The higher concentration of bis forms rigid gels with smaller pores due to more cross-linking leading to polymerization and vice versa.