Cell culture on permeable supports results in greater morphological and/or physiological differentiation of many cell types. They allow access to the basolateral and apical domains of polar cells. These track-etched polyethylene terephthalate (PET) membranes have individual, cylindrical pores and are tissue culture-treated on both sides for cell growth. The PET housing is not tissue culture-treated in order to limit cell growth on the side walls of the insert. High-density translucent membranes are recommended for transport studies. Sterilized by gamma irradiation. Case of 48. Falcon® (a Corning Brand) #: 353494.