Stratum corneum keratin and associated protein–water matrix (SC matrix)

The stratum corneum keratin and associated protein–water matrix is the primary physical and chemical barrier of the human skin, located in the outermost layer of the epidermis. It consists of corneocytes filled with keratin intermediate filaments bundled by filaggrin, surrounded by a complex of hygroscopic molecules known as the natural moisturizing factor (NMF) and an extracellular lipid matrix. This matrix is essential for maintaining skin hydration, providing mechanical resilience, and preventing the entry of pathogens and allergens. In diseases such as atopic dermatitis and ichthyosis, defects in proteins like filaggrin or a reduction in NMF lead to barrier dysfunction, increased transepidermal water loss, and chronic inflammation. Therapeutic interventions target this matrix using humectants to restore water-binding capacity and emollients to repair the structural integrity of the barrier. Understanding the dynamics of this protein-water environment is critical for developing effective topical treatments for various dermatological conditions.

Other names

Stratum corneum barrierSkin moisture barrierKeratin-filaggrin matrixCorneocyte protein matrixNatural moisturizing factor (NMF) complex

Humectants (e.g., urea, glycerin) bind water within the protein-water matrix to increase hydration; emollients and occlusives (e.g., petrolatum, ceramides) reinforce the lipid-protein structure to prevent transepidermal water loss; keratolytic agents (e.g., salicylic acid) disrupt keratinocyte adhesion to promote desquamation.