Human Epidermal Keratinocyte

Human Epidermal Keratinocytes (HEKs) are primary epithelial cells isolated from the epidermis of human skin, typically obtained from neonatal foreskin or adult skin tissue. These cells represent the predominant cell type of the epidermis and are responsible for the formation, maintenance, and regeneration of the stratified squamous epithelium. In vitro, HEKs display a characteristic cobblestone morphology when cultured under low-calcium conditions that support a proliferative, basal-like state. Upon calcium elevation or differentiation-inducing conditions, they undergo a well-defined program of stratification and terminal differentiation, recapitulating key aspects of epidermal development.

Because HEKs maintain many physiological characteristics of native epidermis, they are widely used in 2D monolayer cultures as well as in advanced 3D organotypic skin equivalents that reproduce epidermal stratification and barrier formation. As primary cells, they have a finite lifespan and limited proliferative capacity, and their phenotype can vary depending on donor source and culture conditions. Therefore, careful control of passage number and differentiation state is essential for experimental reproducibility and for modeling normal skin biology and dermatological disease processes.