Abstract Human epithelial tissues are essential biological barriers that secrete a unique hydrogel known as mucus. Tissues generate distinct types of mucus that provide specific biological functions like hydration, pathogen defense, and mediating the movement substances toward the cell surface. The major component of mucus, mucin proteins, is critical for gel structure and function. Mucins are a diverse family of 20+ proteins characterized by a large, rod-like domain rich serine/threonine with attached saccharides, or glycans. Molecular-level mucus studies have been challenging due to heterogeneous glycan patterns that are tissue and species specific, as well as varied protein expression levels and splicing that result in structures with varied lengths and sequences. Misregulation of mucin expression, splicing, and glycosylation results in altered structures that may affect biological function with outcomes relevant to infection, inflammation, and cancer. Researchers typically utilize mucins isolated from farm animal sources for such studies, but this source suffers from batch-to-batch variation, structures that are not chemically defined and have non-human glycan patterns that cannot be systematically altered. Currently, there is an unmet need for chemically-defined mucins that can be tuned at the molecular level and possess human glycosylation patterns. Such materials are essential to probe the role of these vital biomaterials in health and disease. The proposed research will address this critical need by developing a method to prepare synthetic human mucins, which will be applied to probe glycan-pathogen interactions. Techniques from carbohydrate chemistry, amino acid N-carboxyanhydride (NCA) polymerization, and enzymatic glycosylation, will be combined to generate materials with fully tunable properties. I will generate a panel of chemically-defined mucin glycopolypeptides with varied lengths, amino acid compositions, glycosylation densities, and glycan structures. Structure design will be guided by published glycomic analysis of native human mucins implicated in airway infections. All glycopolypeptides will be fully characterized for physicochemical properties using a variety of spectroscopic, microscopic, and biochemical methods. Mucins and their glycans have previously been shown to affect activity of pathogenic microbes such as adhesion, biofilm formation, and virulence traits. Synthetic mucins will be applied to reveal how glycan presentation affects these pathogenic functions. Such studies are not possible with native mucins since glycosylation cannot be controlled and is typically not even characterized. Overall, I aim to shed light on the molecular structure-function relationship between mucins and microbes. This interdisciplinary approach will combine techniques from multiple fields to answer important questions about infection that cannot be undertaken by biological methods alone. The proposed materials could have therapeutic applic...