What is the difference between PromoCell NHEK and NHEK GM3?

The NHEK (primary human keratinocytes) are isolated in our serum-free Keratinocyte Growth Medium 2 (C-20011), the NHEK GM3 in our improved serum-free and BPE-free Keratinocyte Growth Medium 3 (C-20021). Both, NHEK and NHEK GM3 are available from single or from pooled donors isolated from the epidermis of juvenile foreskin or adult skin.