Sterile Syringe FiltersSterile Syringe Filters Thermo Scientific Nalgene sterile syringe filters are ideal for sterilizing (0. 2 micron) or clarifying biological solutions, such as cell culture and microbial media, reagents and additives, proteinaceous solutions, and buffers. PES (polyethersulfone) Lowest protein binding and extractables, fast flow rates; best choice for media SFCA (surfactant free cellulose acetate) Low protein binding, lower extractables than standard CA;