Fully synthetic mucous solutions reproduce rheological response of natural mucous

Mucus , a complex fluid produced by every living organism, has many essential functions including acting as an effective barrier layer in various bodily processes. The primary component of mucuses are mucins – highly glycosylated, linear polypeptides. However, a major concern with studying mucin properties is that mucus is often full of non-mucin constituents that affect the rheological response, and purifying mucus is difficult. In this study, fully synthetic mucins have been prepared and aqueous solutions of these mucins studied for comparison to the rheological response of natural mucin solutions. The purity and structural control of these synthetic mucins provide a model system where the mechanistic sources of the mucus' rheological response can be isolated and identified. Flow curves (viscosity vs. shear rate) and oscillatory measurements (storage and loss modulus vs. frequency) reveal shear thinning behavior similar to natural mucus, aging that is evocative of gelation, and a marked dependence on concentration. We will discuss the origins of these effects and their relevance for understanding mucus behavior more broadly.