We purify mucin glycoproteins, reconstitute them into mucus model systems, and study their barrier properties as well as lubricating properties – both at physiological and pathological conditions, e.g., when contaminated by particulate matter. Moreover, owing to their multifunctional properties and great biocompatibility, we make use of mucins to develop nanomaterials that can deliver a wide variety of cargo molecules. Here, we take the advantage of disease-specific patterns and use them as triggers to engineer rationally designed drug delivery systems. Finally, we generate mucin coatings on medical devices such as contact lenses, catheters and endotracheal tubes to prevent wear formation on tissues and reduce biofouling events.