Mucosal surface and mucus layer

The mucosal surface and mucus layer represent a complex, semi-permeable biological barrier lining the respiratory, gastrointestinal, and urogenital tracts (Bansil & Turner, 2018). This layer is primarily composed of water, electrolytes, and high-molecular-weight glycoproteins known as mucins, which form a viscoelastic gel (Cone, 2009). Its primary biological functions include protecting the underlying epithelium from mechanical stress, pathogens, and toxins, while simultaneously allowing for the exchange of nutrients and gases (Fahy & Dickey, 2010). In diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD), mucus becomes hyperviscous and accumulates, leading to airway obstruction and recurrent infections (Fahy & Dickey, 2010). Conversely, in conditions like inflammatory bowel disease (IBD), the mucus barrier is often thinned or compromised, allowing luminal bacteria to trigger inflammation (Ensign et al., 2012). Pharmacological interventions target this layer through mucolytics like N-acetylcysteine, which reduce mucus viscosity by breaking disulfide bonds, or through mucoadhesive drug delivery systems designed to enhance the residence time of medications on mucosal surfaces (Ensign et al., 2012). Understanding the physicochemical properties of the mucus layer is critical for optimizing drug delivery and managing chronic inflammatory and infectious diseases (Bansil & Turner, 2018).

Other names

Mucus barrierMucosal barrierMucus membraneGlycocalyx

Mucolysis via reduction of disulfide bonds in mucin polymers, enzymatic degradation of extracellular DNA, stimulation of mucin secretion, and mucoadhesion for localized drug delivery.