Learn how to use this product The MEXi-CM culture medium is an affordable, serum-free, chemically defined medium specifically developed for the growth of high-density MEXi-293E cells. It has a low biotin content (120 µg/l), which enables efficient and convenient purification using the Strep-tag® technology. The Mexi-CM culture medium is part of the MEXi mammalian expression system. The MEXi mammalian expression system includes the MEXi-293E cell line, various pDSG expression vectors, the MEXi-CM culture medium, and the MEXi-TM transfection medium.