Is it feasible to store the melanocytes for a second time in liquid nitrogen after subculture similar to cell lines?

Upon arrival; you can either defrost the cells immediately and seed them in a TC vessel or store the vial in liquid nitrogen until needed. It is possible to re-freeze normal human cells but PromoCell does not recommend it; because each freezing cycle leads to a loss in proliferation potential. If you want to freeze them; please use Cryo-SFM (C-29910) which is a serum-free freezing medium that prevents the possibility that any serum is introduced into your serum-free cell culture system. It is also recommended to freeze the cells at an early passage.